Wiring Voting AI V33 en PDF

Wiring and Voting
Architectures for failsafe

Analog Input Modules
(F-AI) of the ET 200M
Siemens
SIMATIC Safety Integrated for process automation Industry
Online
https://support.industry.siemens.com/cs/ww/en/view/24690377 Support
Warranty and liability
Warranty and liability
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Wiring and Voting Architectures for failsafe F-AI

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Table of Contents
Table of Contents
Warranty and liability ................................................................................................... 2
1 Automation functions ........................................................................................ 6
1.1 Functionality of the functional example ................................................ 6
1.2 Presented architectures ....................................................................... 8
1.3 Properties for the fail-safe analog input module .................................. 9
2 Hardware configuration and wiring of one sensor (1oo1) and one F-
AI (1oo1) ........................................................................................................... 12
2.1 PFD calculation .................................................................................. 13
2.2 Wiring ................................................................................................. 13
2.2.1 Conventional wiring ............................................................................ 13
2.2.2 Wiring using an MTA (Marshalled Termination Assembly) ................ 17
2.3 Parameters for hardware configuration .............................................. 18
2.4 Configuring the logic ........................................................................... 21
2.4.1 Configuring with Safety Matrix ........................................................... 21
2.4.2 Configuring with CFCs ....................................................................... 24
Logic without channel fault evaluation (1oo1) .................................... 24
Logic with channel fault evaluation .................................................... 25
3 Hardware configuration and wiring of one sensor (1oo1) with
redundant F-AI (2oo2) ..................................................................................... 26
3.1 PFD calculation .................................................................................. 27
3.2 Wiring ................................................................................................. 27

3.4 Creating the Logic .............................................................................. 34
Logic without channel fault evaluation ............................................... 35
4 Hardware configuration and wiring of two sensors (1oo2) and one F-
AI with evaluation in the module (1oo1) ........................................................ 38
4.1 PFD calculation .................................................................................. 39
4.2 Wiring ................................................................................................. 40
5 Hardware configuration and wiring of two sensors (1oo2) with
redundant F-AI and evaluation in the modules (2oo2) ................................ 55
5.1 PFD calculation .................................................................................. 56
5.2 Wiring ................................................................................................. 57

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Table of Contents

Logic without channel fault evaluation (1oo2 in the F-AI) .................. 62
6 Hardware configuration and wiring of two sensors (1oo2) and
evaluation in the user program ...................................................................... 65
6.1 Option 1: with one module.................................................................. 66
6.1.1 PFD calculation (option 1) .................................................................. 67
6.2 Option 2: with two modules ................................................................ 67
6.2.1 PFD calculation (option 2) .................................................................. 68
6.3 Wiring ................................................................................................. 69
7 Hardware configuration and wiring of two sensors (1oo2) with
redundant F-AI (2oo2) and evaluation in the user program ........................ 84
7.1 PFD calculation .................................................................................. 85
7.2 Wiring ................................................................................................. 86

8 Hardware configuration and wiring of three sensors and three F-AIs
(2oo3) with evaluation in the user program .................................................. 94
8.1 PFD calculation .................................................................................. 96
8.2 Wiring ................................................................................................. 97
8.3 Parameters for hardware configuration ............................................ 101
8.4 Creating the Logic ............................................................................ 104
8.4.1 Configuring with Safety Matrix ......................................................... 104
8.4.2 Configuring with CFCs ..................................................................... 107
9 Hardware configuration and wiring of three sensors (2oo3) with
redundant F-AI (2oo2) and evaluation in the user program ...................... 112
9.1 PFD calculation ................................................................................ 114
PFD calculation formula ................................................................... 114
9.2 Wiring ............................................................................................... 115
9.2.1 Conventional wiring .......................................................................... 115
9.3 Parameters for hardware configuration ............................................ 116
9.4 Creating the Logic ............................................................................ 118
9.4.1 Configuring with Safety Matrix ......................................................... 118
9.4.2 Configuring with CFCs ..................................................................... 118
Logic without channel fault evaluation ............................................. 118
Logic with channel fault evaluation .................................................. 121

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Table of Contents
APPENDIX ................................................................................................................. 123

10 Calculating the PFD value............................................................................. 123
11 Recommendations for power supply and grounding measures .............. 125
11.1 Power supply .................................................................................... 125
11.1.1 Infeed................................................................................................ 125
11.1.2 System power supply ....................................................................... 125
11.2 Grounding ......................................................................................... 126
11.2.1 Objective........................................................................................... 126
11.2.2 Implementation ................................................................................. 126
12 MTA (Marshalled Termination Assembly) ................................................... 129
13 Glossary ......................................................................................................... 132
14 Links andLiterature ....................................................................................... 133
15 Change documentation ................................................................................. 133

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1 Automation functions
1.1 Functionality of the functional example
Task
Several analog signals in a system are to be monitored in a safety-oriented
manner. Depending on the importance and risk of failure, there are several ways to
wire and evaluate the signals. For instance, the evaluation can be performed in the
analog input module and/or in the user program.
Fig. 1-1 illustrates an example of a plant unit, in which the valves (BV-100A and
BV-100B) require fail-safe closing, depending
 on pressure,
 the filling level and
 the temperature.
Fig. 1-1: Example 1 - overview

PT- 400A
3 Pressure Transmitters
 Failsafe Analog Input 2 Block Valves

Signals PT- 400B Failsafe Discrete

 2 oo3 Voting in the Output Signals
CPU  Valves in Series
(Normally -Open,
PT- 400C 1 Pair of Fail -Close)
S7-400FH CPUs  1 oo2 Voting
 Redundant Arrangement
 Failsafe
2 Temperature TT-200A
Transmitters
 Failsafe Analog Input Safety BV-100A BV-100B
Signals
TT-200B Logic
 1 oo2 Voting in the
CPU
LSH-100A
3 Level Switches
 Failsafe Discrete
Input Signals LSH-100B
 2 oo3 Voting in the
CPU
LSH-100C
This functional example shows various possibilities of wiring and evaluating safety-
related signals.

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Solution
Fig. 1-2 illustrates a plausible plant unit layout, in which different connection and
evaluation architectures of the analog signals are used.
Fig. 1-2: Example 1 – system configuration

PT-100A F-AI
0 CPU
TT-200A PT-100 Voting Logic
1 F_CH_AI
2oo3
PT-100B F-AI
0
TT-200B
1 F-DO BV-100A
0
PT-100C F-AI
TT-200 Voting Logic BV-100 Voting Logic 1
0
F_CH_AI F_CH_DO
1oo2 OR
F-DO
0
LSH-100A F-DI
LSH-100 Voting Logic BV-100B
0
F_CH_DI 1
2oo3
LSH-100B F-DI
0
LSH-100C F-DI
0
Note The fail-safe analog input module SM 336; F-AI 6 x 0/4 ... 20 mA HART with
order number 6ES7 336-4GE00-0AB0 is used in all functional examples. This is
hereafter referred to as F-AI.

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1.2 Presented architectures

Recommended Architectures
The following architectures are presented in this Application Example:
 One sensor (1oo1) and one F-AI (1oo1)
Typical application when a single sensor has the required safety integrity level
and there is no need for increased availability (explained in Chapter 2).
 One sensor (1oo1) and redundant F-AI (2oo2)
Typical application when a single sensor has the required safety integrity level
and there is a need for increased availability. (explained in Chapter 3).
 Two sensors (1oo2) and one F-AI with evaluation in the F-AI (1oo1)
Typical application when a single sensor does not have the required safety integrity
level and there is no need for increased availability (explained in Chapter 4).
 Two sensors (1oo2) and redundant F-AI with evaluation in the F-AI (2oo2)
level and there is a need for increased availability (explained in Chapter 5).
 Two sensors (1oo2) with evaluation in the user program
level and the data of both sensors must be visible in the automation system (explained
in Chapter 6).
 Two sensors (1oo2) and redundant F-AI (2oo2) with evaluation in the user
program
level and the data of both sensors must be visible in the automation system. This
architecture can be configured as redundant F-AI (2oo2) for increased availability
(explained in Chapter 7).
 Three sensors (2oo3) with evaluation in the user program
Typical application when several sensors are required in order to achieve the
required safety integrity level and there is a desire for increased availability
(explained in Chapter 8 and Chapter 9).

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1.3 Properties for the fail-safe analog input module

Properties of the F-AI
 6 analog inputs with galvanic isolation between channels and the backplane bus
 Input ranges:
– 0 to 20 mA
– 4 to 20 mA
 Short-circuit proof power supply of 2 or 4-wire transmitter via the module
 External sensor supply possible
 Group fault display (SF)
 Safety mode display (SAFE)
 Display for channel-specific fault (Fx)
 Display for HART status (Hx) (if you have activated HART communication for a channel
and HART communication is running, the green HART status display lights up.)
 Programmable diagnostics
 Programmable diagnostic interrupt only in safety mode
 SIL3/Cat.4/PLe can be achieved without safety protector
 HART communication
 Firmware update using HW Config

 Identification data I&M
 Can be used with PROFIBUS DP and PROFINET IO
Use of inputs
You can use the inputs as follows:
 Each of the 6 channels for current measurement
– 0 to 20 mA (without HART utilization)
– 4 bis 20 mA (with/without HART utilization)
– Functional range of HART communication: 1.17 to typ. 35 mA
Connection diagrams of the F-AI

The following pictures provide an overview of the address and terminal
assignments of the F-AI (SM 336) considered in this document.

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Fig. 1-3: SM 336 address assignment; F-AI 6 x 0/4...mA HART
Fig. 1-4: SM 336 front view; F-AI 6 x 0/4...mA HART


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Fig. 1-5: SM 336 connection and basic circuit diagram; F-AI 6 x 0/4...mA HART
Fig. 1-6: SM336 channel numbers; F-AI 6 x 0/4...20mA HART
Recommendation
You are strongly advised to use the short-circuit proof internal sensor supply of the
module. This internal sensor supply is monitored and its status is indicated by the
Fx LED (see picture: Front view of SM 336 front view; F-AI 6 x 0/4 ... 20 mA HART).

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2 Hardware configuration and wiring of one sensor (1oo1) and one F-AI (1oo1)
2 Hardware configuration and wiring of one

sensor (1oo1) and one F-AI (1oo1)
The one-sensor evaluation scheme (or 1oo1) refers to applications that do not
require increased availability. 1oo1 evaluation means that only one sensor is
present. If the sensor indicates a trigger condition, the safety logic is triggered.
Note The I/O module in this architecture is certified for the safety integrity level SIL3.
However, to be SIL-compliant, the entire safety function – including the field
devices – must be assessed according to IEC 61508/IEC 61511.
In the 1oo1 basic architecture, one sensor is wired to one F-AI channel
(in Fig. 2-1 on Channel 0).
Fig. 2-1: F-AI – 1oo1 architecture
F-AI
Ch 0..5
Sensor 1
0
CPU
1oo1
Voting
F_CH_AI Logic
With a hardware configuration according to Fig. 2-1, it is possible to achieve a

maximum of SIL3.
The following table shows you when the safety function can be triggered by a
corresponding logic.
Table 2-1: Failure combinations

Failed component detected? Tripping of the safety
Sensor 1 F-AI function possible?
No No Yes (not required)

X Yes Yes
Yes X Yes

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2.1 PFD calculation

The PFD (Probability of Failure on Demand) value describes the probability of
failure of the safety function.
PFD calculation formula

The PFD value for this wiring and evaluation architecture is calculated using this
formula:
PFDIn = PFDSensor + PFDF-AI + PFDCPU
The PFDF-AI and PFDCPU values are located in Section 10.

1
The PFDSensor value for one 1oo1 sensor is calculated using the following formula :
2.2 Wiring
2.2.1 Conventional wiring
In the 1oo1 evaluation scheme, the sensor can be supplied with voltage as follows:
 internally through the F-AI or
 via an external voltage source
Internal power supply

Special features of the F-AI with internal power supply include:
 The short-circuit between sensor supply voltage Vsn and Mn+ is controlled.
 It is possible to detect undervoltage from the transmitter by reading back the
sensor supply in the F-AI.
Wiring examples
illustrates a wiring example for a 2-wire transmitter.

Fig. 2-3 illustrates a wiring example for a 4-wire transmitter.
In both figures, the transmitter is wired to channel 0 (terminals 3, 4, 5) and is
powered by the F-AI.
1
The formula was taken from IEC61508, IEC 61511 and VDI 2180 sheet 4

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Wiring example for a 2-wire transmitter
Figure 2-2: Wiring for a 2-wire transmitter (internal sensor supply)
2-Wire
Current
Transmitter
Wiring example for a 4-wire transmitter
Fig. 2-3: Wiring of a 4-wire transmitter (internal sensor supply)
4-Wire
Current
Transmitter

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External power supply (2-wire transmitter)

Fig. 2-4 illustrates an external voltage source on a 2-wire transmitter. The sensor is
wired to Channel 0 (terminals 4, 5). It is recommended to connect the M potentials
together.
CAUTION The F-AI cannot detect an under-voltage in the transmitter. Therefore, you
should use transmitters with under-voltage detection.
Fig. 2-4: Wiring of a 2-wire transmitter (external sensor supply)
2-Wire
Current
Transmitter
recommended

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Figure 2-5 illustrates an external voltage source with a 4-wire transmitter. The
sensor is wired to Channel 0 (terminals 4, 5). It is recommended to connect the M
potentials together.
CAUTION The F-AI cannot detect an under-voltage in the transmitter. Therefore, you
should use transmitter with under-voltage detection.
Fig. 2-5: Wiring of a 4-wire transmitter (external sensor supply)
4-Wire
Current
Transmitter
recommended

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2.2.2 Wiring using an MTA (Marshalled Termination Assembly)
Siemens provides MTAs (Marshalled Termination Assemblies). By using an F-AI

MTA for this evaluation scheme, the wiring between the sensors and the ET 200M
signal modules is greatly simplified as it already includes the necessary diodes and
Zener diodes.
You can find further relevant information in the Chapter
"MTA (Marshalled Termination Assembly)".
Fig. 2-6: MTA


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2.3 Parameters for hardware configuration

To configure, select the F-AI in the STEP 7 hardware catalog and add it into an
existing ET 200M station. Select meaningful icon names for the analog channels in
order to facilitate later configuration.
You can find an example for a hardware configuration using an F-AI in Fig. 2-7.
The sensor signal in this example is wired to Channel 0 of the F-AI. Please note
that the use of an F-AI MTA is not taken into account in the hardware configuration.
For further information on hardware configuration, see \4\ in the "Links and
Literature" chapter.
Fig. 2-7: Symbol processing

The required parameters for operating the F-AI are set in the object properties of
the F-AI added (see Fig. 2-8).
The parameters are summarized in Table 2-2.

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Fig. 2-8: Hardware parameters

Table 2-2: Hardware configuration parameters

Parameter Description / Recommendations Desired setting
or permissible
value range
F-parameters
F_destination_address PROFIsafe address of the 1-1022 or
F-signal module (setting via DIP switch). 0000000001...
1111111110
F_monitoring_time Monitoring time for safety-related 0...65535ms

(ms) communication between the CPU and the Default 2500ms
F-AI.
Remark: A worksheet is available on the
Siemens Support website to help users
calculate
F-monitoring times (see \10\ in the "Links
and Literature" chapter).

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or permissible
value range
Module parameters
Diagnostic interrupt A diagnostic interrupt is triggered by Release / lock
various error events that can be detected
by the module. These events are then
reported to the CPU.
Remark:
If the diagnostic interrupt is released at
the module level, individual diagnostic
events must be also activated at the
channel level.
Behavior after channel Passivate the entire module/ passivate Module/
faults the channel. Channel
Remark:
Irrelevant for F systems
HART_Gate Acts as a fail-safe "main switch" across Off/
the modules. On/
HART communication is blocked with switchable
"Off".
HART communication is enabled with
"On".
The HART modem can be switched out of
the safety program for maintenance

purposes with "switchable".
Noise Selection for matching the integration time 50/60 Hz
suppression of the ADC to the network used.
(Hz) The integration time is:
– 20 ms at 50 Hz
– 16.66 ms at 60 Hz
Evaluation of the Channel activation by specifying the 1oo1 (1v1)
sensors encoder evaluation.
– Deactivated
– 1oo1 (1v1)
– 1oo2 (2v2)
If 1oo1 is selected, the following
parameters are not available:
– Discrepancy time
– Tolerance range
– Unit value
Measuring range Measuring range selection for the 0...20 mA
channel. 4...20 mA
F_wire-break Select whether or not to enable wire Release / lock
detection break monitoring for the channel.
Smoothing Number of measuring cycles through 1, 4, 16, 64
which smoothing is carried out.
Note The hardware parameters and configuration window may differ from those in this
section due to the version of the module and hardware configuration pack. You
can find further information in the module's documentation.

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2.4 Configuring the logic

2.4.1 Configuring with Safety Matrix
Once the hardware has been configured, you can deploy the SIMATIC Safety
Matrix Engineering Tool (for further relevant information, see \5\ in the "Links and
Literature" chapter).
Fig. 2-9 illustrates how a cause for monitoring an input TAG is configured in the
Safety Matrix. The following settings must be used:
 Input Type: Analog
 1 input
 Function type: Normal (1oo1 evaluation)
 Enter the signal name in Tag 1 (e.g. F_TAG1001_X) or press the "I/O" button
to select the symbol from the symbol table.
Fig. 2-9: Safety Matrix – Configure


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As shown in Fig. 2-10, there are additional analog parameters that must be
configured for the cause:
 Required parameters:
– Limit type: MAX or MIN
– Limit value
 Optional parameters:
– Pre-alarm
– Hysteresis
– Units:
Fig. 2-10: Safety Matrix - Analog parameter

If the input TAG goes below or above the limit, the cause activates and triggers the
corresponding effect(s).

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You can also activate additional options (e.g. time delay and bypass option),
depending on the process application.
One configuration option highlighted in Fig. 2-11 is the disconnection in case of a

channel fault. If this option is activated, a channel fault will act as a violation of the
limit and trigger the corresponding effect(s) on a 1oo1 (Function Type: Normal).
Fig. 2-11: Safety Matrix – Options


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2.4.2 Configuring with CFCs
As an alternative to using the Safety Matrix Tool, you can also implement the CPU
logic for reading the input signal by means of the STEP 7 CFC Editor.
There are two ways to implement the CFC logic:
 Without channel fault evaluation
 With channel fault evaluation
Logic without channel fault evaluation (1oo1)

Fig. 2-12 illustrates an example logic created in the CFC Editor for reading an input
signal that does not take a channel fault into account. Please note that this
example starts from a MAX limit and that the output of the evaluation logic is
switched off to reach the safe state (Normal State = 1, Safe State = 0).
Fig. 2-12: CFC Logic – Without channel fault evaluation

Note Depending on the parameter assignment of the "SUBS_ON" block input, the
F_CH_AI block outputs the substitute value or the last valid process value set at
the "SUBS_V" input in the event of a channel fault at the "V" output.
In the configuration shown (SUBS_ON = 0 on the F-channel driver), the last valid
value is used in case of error. It is not possible to predict whether this value is
above or below the limit.
The example logic in Fig. 2-12 works as follows:

 If the process value is in the normal range (in this case, lower than 90), the
output of the evaluation logic is 1 (i.e., no trigger command).
 If the process value exceeds the limit (in this case, greater than or equal to 90),
the output of the evaluation logic is 0 (i.e., trigger command).
 The output of the logic should be connected to the corresponding shutdown logic.
To create the logic, create an F_CH_AI F-channel driver for the analog input signal
and connect it to the symbol or address of the sensor connected to the F-AI
(e.g. F_TAG1001_X). Use a limit block (F_LIM_HL or F_LIM_LL) to compare the
signal with the tripping limit value.

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Logic with channel fault evaluation
Fig. 2-13 illustrates a sample logic created in the CFC Editor for reading a single
input signal that takes a channel fault into account. Please note that this example
starts from a MAX limit and that the output of the evaluation logic is switched off
to reach the safe state (Normal State = 1, Safe State = 0).
Fig. 2-13: CFC logic – With channel fault evaluation

The example logic in

Fig. 2-13 works as follows:
 In the normal range (here: lower than 90) and with an undisturbed process
value, the output of the evaluation logic is 1 (i.e., no trigger command).
 In case of upper limit violation (here: greater than or equal to 90) and with an
undisturbed process value, the output of the evaluation logic is 0
(i.e., trigger command).
 If there is a channel fault, the output of the evaluation logic is 0
The necessary steps to create the logic are described below:

 Create an F_CH_AI channel driver for the analog input signal and connect it to
the address of the sensor connected to the F-AI (e.g. F_TAG1001_X).
Use a limit block (F_LIM_HL or F_LIM_LL) to compare the signal with the
tripping limit value.
 Create an AND operation for the following signals in order to generate the
signal for the trigger command:
– Negated value of the limit module (QHN or QLN)
– Negated value of the channel fault output (QBAD) from the channel
driver block

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3 Hardware configuration and wiring of one sensor (1oo1) with redundant F-AI (2oo2)
3 Hardware configuration and wiring of one

sensor (1oo1) with redundant F-AI (2oo2)
This architecture increases the availability of the system by means of redundant
F-AI modules. The CPU performs a 2oo2 evaluation of the signals from the F-AI.
Note The I/O modules in this architecture are certified for achieving the safety integrity
level of SIL3. However, to be SIL-compliant, the entire safety function – including
the field devices – must be assessed according to IEC
61508/IEC 61511.
In this architecture, a single sensor is wired to a redundant F-AI. A block diagram is

shown in Figure 2-17.
In Fig. 3-1, the sensor on Channel 0 is wired to both F-AIs. The F-AIs are
configured as redundant in the hardware configuration. Only one analog F-channel
driver is required. The F-channel driver chooses from the incoming analog signals.
Fig. 3-1: Redundant F-AI – 1oo1 architecture

F-AI
Ch 0..5
0
CPU
1oo1
Voting
F_CH_AI Logic
Sensor 1
F-AI
Ch 0..5

maximum of SIL3.

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function possible?
Sensor 1 F-AI 1 F-AI 2
No No No Yes (not required)
No No Yes Yes (not required)
No Yes No Yes (not required)
X Yes Yes Yes
Yes X X Yes
Note The redundancy of the I/O modules does not increase the safety integrity level.
3.1 PFD calculation


The PFD value for this wiring & evaluation architecture is calculated using this
formula:
PFDIn = PFDSensor + 2 PFDF-AI + PFDCPU

2
3.2 Wiring
An example for the 1oo1 evaluation scheme with redundant F-AI can be found in
Fig. 3-2 and in Fig. 3-3. The sensor is wired to Channel 0 (terminals 3, 4, 5) of both F-AIs.
2
The formula was taken from IEC61508, IEC 61511 and VDI 2180 sheet 4

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Special feature
 The short-circuit between sensor supply voltage Vsn and Mn+ is controlled.
 It is possible to detect undervoltage from the transmitter by reading back the
sensor supply in the F-AI.
 It is necessary to include the external elements in the application-specific
safety consideration, i.e.: the external elements required for implementing the
redundancy (e.g. Zener diodes) must be included in the safety consideration).
Fig. 3-2: A 2-wire transmitter, internal sensor supply with module redundancy
2-Wire
Current
Transmitter
Fig. 3-3: A 4-wire transmitter, internal sensor supply with module redundancy
4-Wire
Current
Transmitter

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Fig. 3-4 illustrates an external voltage source on a 2-wire transmitter. The sensor
signal is looped through the Channels 0 (terminals 4, 5) of the two redundant
modules.
It is recommended to connect the M potentials together.
Fig. 3-4: A 2-wire transmitter, external sensor supply with module redundancy
2-Wire
Current
Transmitter
recommended

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Figure 3-5 illustrates an external voltage source with a 4-wire transmitter. The
sensor signal is looped through the Channels 0 (terminals 4, 5) of the two
redundant modules. It is recommended to connect the M potentials together.
It is recommended to connect the M potentials together.
Fig. 3-5 A 4-wire transmitter, external sensor supply with module redundancy
4-Wire
Current
Transmitter
recommended

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Zener diodes.
Fig. 3-6: MTA


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The F-AIs are configured in STEP 7 HW Config for the 1oo1 evaluation scheme with
redundant F-AI. Fig. 3-7 illustrates an example of a hardware configuration.
In this example, there is an ET 200M rack (with IM153-2 interface module for
PROFIBUS) with PROFIBUS address 3 and a second ET 200M rack with PROFIBUS
address 4. Each ET 200M contains one F-AI in slot 4. For further information on
hardware configuration, see \4\ in the "Links and Literature" chapter.
Fig. 3-7 : Redundant F-AI

The two F-AIs must be configured as a redundant pair in the HW Config. The F-AI
redundancy settings can be accessed through the object properties of one of the F-AIs.
For the sake of the hardware configuration example in Fig. 3-7, the redundancy
settings are made on the F-AI located in the ET 200M rack with the PROFIBUS
address 3. The interface of the redundancy settings is shown in Fig. 3-8 and the
settings are summarized in Table 3-2.

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Fig. 3-8: Redundant F-AI - Redundancy parameters

Table 3-2 : Redundant F-AI - Redundancy parameters

or permissible
value range
Redundancy Shows whether the F-AI is acting as part of 2 modules
a redundant pair or not.
Remark:
For redundancy, the parameter must be set
to 2 modules.
Redundant module Used to select the redundant partner
module.
If the redundancy settings have been made, the other hardware parameters can be
set in one of the redundant F-AIs. The settings are automatically applied to the
redundant module.

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3.4 Creating the Logic

Although this evaluation scheme uses redundant F-AIs, only one F_CH_AI F-channel
driver is needed in the logic. The F-channel driver can be added and configured
automatically from the SIMATIC Safety Matrix or manually using the STEP 7 CFC
Editor. In both cases, the F-channel driver must be connected to the analog sensor
signal of the F-AI with the lowest I/O address.
The logic is compiled when the F-channel driver is configured and the logic is fully
available. If the option to generate module drivers is enabled during compilation,
the corresponding F_PS_12 module drivers are automatically added to the logic
and configured during the compilation. The F-channel driver selects the valid signal
and, in the event of a fault, switches to the signal of the redundant module.
After the sensor has been added to the hardware configuration, the evaluation
logic for the signal can be implemented in the user program. One method is to use
the SIMATIC Safety Matrix Engineering Tool (for further relevant information, see
\5\ in the "Links and Literature" chapter).
The actual evaluation logic for monitoring a single sensor with redundant F-AI is
the same as that described in the Section 2.4.1 (Configuring with Safety Matrix).

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As an alternative to using the Safety Matrix Tool, you can also implement the CPU
logic for reading the input signal by means of the STEP 7 CFC Editor.
Logic without channel fault evaluation

Fig. 3-9 illustrates an example logic created in the CFC Editor for reading an input signal
from redundant F-modules, which does not take a channel fault into account. Please note
that this example starts from a MAX limit and that the output of the evaluation logic is

In the logic shown (SUBS_ON = 0 on the F-channel driver), the last valid value
of both F-AI modules is used in case of error. It is not possible to predict whether
this value is above or below the limit.
Note When redundant F-AIs are used, activate the discrepancy evaluation on
F_CH_AI by setting the input "DISC_ON" to 1, "DISC_TIM" with a delay time,
and "DELTA" to a max. deviation. Interconnect the "DISCF" output to a message
block to alert the operator when there is a deviation between the redundant
signals.

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 The F_CH_AI F-channel driver evaluates the two sensor signals and sends a
value to the logic for further processing.
 If the process value is in the normal range (in this case, lower than 90), the
output of the evaluation logic is 1 (i.e., no trigger command).
 If the process value exceeds the limit (in this case, greater than or equal to 90),
To create the logic, create an F_CH_AI F-channel driver for the analog input signal
and connect it to the symbol on the F-AI with the lowest address
(e.g. F_TAG1001_X to EW512). Use a limit block (F_LIM_HL or F_LIM_LL) to
compare the signal with the tripping limit value.

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Fig. 2-13 illustrates a sample logic created in the CFC Editor for reading an input
signal of the redundant F-AI that takes a channel fault into account. Please note
that this example starts from a MAX limit and that the output of the evaluation logic
is switched off to reach the safe state (Normal State = 1, Safe State = 0).
Fig. 3-10 : CFC logic – With channel fault evaluation

signals.

 In the normal range (here: lower than 90) and with an undisturbed process
value, the output of the evaluation logic is 1 (i.e., no trigger command).
 In case of upper limit violation (here: greater than or equal to 90) and with an
undisturbed process value, the output of the evaluation logic is 0
 If both F-AIs report a channel fault, the output of the evaluation logic is 0
 Create an F_CH_AI F-channel driver for the analog input signal and connect it
to the symbol on the F-AI with the lowest address (e.g. F_TAG1001_X to
EW512). Use a limit block (F_LIM_HL or F_LIM_LL) to compare the signal with
the tripping limit value.
– Negated value of the channel fault output (QBAD) from the F-channel driver

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4 Hardware configuration and wiring of two sensors (1oo2) and one F-AI with evaluation in the
module (1oo1)
4 Hardware configuration and wiring of two

sensors (1oo2) and one F-AI with
evaluation in the module (1oo1)
The two-sensor or 1oo2 evaluation scheme refers to applications that require two
sensors to achieve the required safety integrity level. 1oo2 evaluation means that
only one of two sensors has to trigger, i.e., the safety logic triggers if one of the
sensors indicates a trigger condition. In this evaluation scheme, the 1oo2
evaluation is done in the F-AI.
Note The I/O modules in this architecture are certified for the safety integrity level
SIL3. However, to be SIL-compliant, the entire safety function – including the
field devices – must be assessed according to IEC 61508/IEC 61511.
In the 1oo2 architecture with evaluation in the F-AI, two sensors are wired to one
F-AI. A block diagram is displayed in Fig. 4-1.
When the 1oo2 evaluation is activated for a channel pair (0/3, 1/4, 2/5), the F-AI
performs a discrepancy analysis between the two input signals. One of the process
values (MIN/MAX) is forwarded to the CPU depending on the parameter assignment.
The system uses the address of the channel with the lowest number. In Fig. 4-1,
the first sensor on Channel 0 is wired to the F-AI. The second sensor must then be
wired to Channel 3.
Fig. 4-1: 1oo2 evaluation in the F-AI – architecture

F-AI CPU
Ch 0..5
Sensor 1 Voting
0 F_CH_AI Logic
Evalution
1002
Sensor 2
3

maximum of SIL3.

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module (1oo1)

function possible?
Sensor 1 Sensor 2 F-AI
X X Yes Yes
X Yes X Yes
Yes X X Yes
4.1 PFD calculation


formula:

3
The PFDSensor for one 1oo2 sensor is calculated using the following formula :
3
The formula was taken from IEC61508, IEC 61511 and VDI 2180 sheet 4, see Appendix

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module (1oo1)
4.2 Wiring
In the 1oo2 evaluation scheme, the F-AI or an external voltage source can supply
the sensors with voltage.
Fig. 4-2 illustrates a wiring example for 2-wire transmitters.
The first sensor in the figure is wired to channel 0 (terminals 3 and 4) and the
second sensor is wired to channel 3 (terminals 12 and 13).
Fig. 4-2: 1oo2 evaluation in the F-AI: 2-channel, 2-wire transmitter, internal supply
2-Wire
Current
Transmitter
2-Wire
Current
Transmitter
Process variable is acquired with two

mechanically separate sensors.

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module (1oo1)

The first sensor in the diagram is wired to channel 0 (terminals 4 and 5) and the
second sensor is wired to channel 3 (terminals 13 and 14).
Fig. 4-3: 1oo2 evaluation in the F-AI: 2-channel, 4-wire transmitter, internal supply
4-Wire
Current
Transmitter
4-Wire
Current
Transmitter

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module (1oo1)
Fig. 4-4 illustrates a wiring example for 2-wire transmitters with external power supply
and Fig. 4-5 illustrates a wiring example for 4-wire transmitters with external power
supply.
The first sensor in both diagrams is wired to channel 0 (terminals 4 and 5) and the
second sensor to channel 3 (terminals 13 and 14). It is recommended to connect the
M potentials together.
Fig. 4-4: 1oo2 evaluation in the F-AI: 2-channel, 2-wire transmitter with external supply
2-Wire
Current
Transmitter
recommended
2-Wire
Current
Transmitter

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module (1oo1)
Fig. 4-5: 1oo2 evaluation in the F-AI: 2-channel, 4-wire transmitter with external supply
4-Wire
Current
Transmitter
recommended
4-Wire
Current
Transmitter

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module (1oo1)

Zener diodes.
Fig. 4-6 MTA


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module (1oo1)

To configure, select the F-AI in the STEP 7 hardware catalog and insert it into an
existing ET 200M station. Select a meaningful icon name for the analog channel in
order to facilitate later configuration. When selecting the 1oo2 signal for the F-AI,
make sure that only one analog sensor signal is made available to the CPU logic.
Fig. 4-7 illustrates an example of a hardware configuration with one F-AI. The
signal consisting of the two sensors (channel 0 and 3) is forwarded to the CPU at
the first symbol address (EW512). For further information on hardware
configuration, see \4\ in the "Links and Literature" chapter.
Fig. 4-7: 1oo2 evaluation in the F-AI symbol processing


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module (1oo1)
Fig. 4-8: 1oo2 evaluation in the F-AI (Hardware Parameters)

Table 4-2: 1oo2 evaluation in the F-AI Parameters for the hardware configuration
or permissible
value range
F-parameters
1111111110
F_monitoring Monitoring time for safety-related 0...65535ms
time communication between the CPU and the Default 2500ms
(ms) F-AI.
calculate

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module (1oo1)

or permissible
value range
Module parameters
Diagnostic interrupt A diagnostic interrupt is triggered by Release / lock
various error events that can be detected
by the module. These events are then
reported to the CPU.
Remark:
If the diagnostic interrupt is released at
the module level, individual diagnostic
events must be also activated at the
channel level.
Behavior after channel Passivate the entire module/ passivate Module/
fault the channel. Channel
Remark:
HART_Gate Acts as a fail-safe "main switch" across Off/
the modules. On/
HART communication is blocked with switchable
"Off".
HART communication is enabled with
"On".

Interference frequency Selection for matching the integration time 50/60 Hz
– 20 ms at 50 Hz
– 16.66 ms at 60 Hz
– Deactivated
– 1oo1 (1v1)
– 1oo2 (2v2)
– Tolerance range
– Unit value
Measuring range Measuring range selection for the 0...20 mA
channel. 4...20 mA
F wire break detection Select whether or not to enable wire Release / lock
break monitoring for the channel.
Smoothing Number of measuring cycles through 1, 4, 16, 64
which smoothing is carried out.
Discrepancy time (ms) Discrepancy time selection 0…30000ms
Tolerance window Define the maximum difference between 0.2…20.0%
% abs. the two signals
Tolerance window Define the maximum difference between 0.2…20.0%
% rel. the two signals

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module (1oo1)

or permissible
value range
Unit value This value is forwarded to the CPU. Must MIN/MAX
be predefined depending on the series-
connected limit value function.

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module (1oo1)

After the 1oo2 evaluation is configured in the F-AI, the CPU logic for reading a
single sensor can be implemented. As pointed out earlier, a 1oo1 evaluation
occurs in the user program after the F-AI handles the 1oo2 signal selection and
provides only one analog sensor signal to the CPU logic. One implementation
method is to use the SIMATIC Safety Matrix Engineering Tool (for further relevant
information, see \5\ in the "Links and Literature" chapter).
Fig. 4-9 illustrates how a cause for monitoring an input TAG is configured in the
Matrix. The following settings must be used:
 1 input
 Function type: Normal (1oo1 evaluation)
 Enter the signal name in Tag 1 (e.g. F_TAG1001_X) or press the "I/O" button
to select the symbol from the symbol table.
The cause is configured with the "Normal" function type.
Fig. 4-9: Safety Matrix – Configure

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module (1oo1)
– Limit value
– Pre-alarm
– Hysteresis
– Units:

If the input TAG goes below or above the limit, the cause activates and triggers the
corresponding effect(s).

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module (1oo1)
You can also activate additional options (e.g. time delay and bypass option),
depending on the process application.
One configuration option highlighted in Fig. 4-11 is the disconnection in case of a
channel fault. If this option is activated, a channel fault at one of the sensor inputs
is evaluated as a trigger signal. Depending on the number of signals and the
function type, the cause can activate and trigger the corresponding effect(s).


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module (1oo1)
As an alternative to using the Safety Matrix Tool, you can implement the CPU logic
for reading the input signal by means of the STEP 7 CFC Editor. The evaluation
logic can be generated in the CFC editor after the two sensor signals have been
added to the hardware configuration and the F-AI performs the 1oo2 evaluation.
Fig. 4-12 illustrates a sample logic for reading a single input signal in the CFC
Editor, which does not take a channel fault into account. Please note that this

In the logic shown (SUBS_ON = 0 on the F-channel driver), the last valid value is
used in case of error. It is not possible to predict whether this value is above or
below the limit.

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module (1oo1)

 The F-AI evaluates the two sensor signals and sends a value to the F-channel
driver for further processing. Depending on how the "Unit value" parameter is
set in the hardware configuration, this value corresponds to either the larger or
the smaller sensor signal or to &H7FFF in case of a discrepancy.
 If the process value is in the normal range (here: lower than 90), the output of
the evaluation logic is 1 (i.e., no trigger command).
 If the process value exceeds the limit (here: greater than or equal to 90), the
output of the evaluation logic is 0 (i.e., trigger command).
 The output of the logic must be connected to the corresponding shutdown logic.
To create the configuration, create an F_CH_AI F-channel driver for the analog input
signal and connect it to the symbol on the address with the lowest channel number
(e.g. F_TAG1001_X to EW512). Use a limit block (F_LIM_HL or F_LIM_LL) to compare
the signal with the tripping limit value.

Fig. 4-13 illustrates a sample logic created in the CFC Editor for reading a single
input signal that takes a channel fault into account. Please note that this example
starts from a MAX limit and that the output of the evaluation logic is switched off to
reach the safe state (Normal State = 1, Safe State = 0).

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module (1oo1)

 The F-AI evaluates the two sensor signals and sends a value to the F-channel
driver for further processing. Depending on how the "Unit value" parameter is
set in the hardware configuration, this value corresponds to either the larger or
the smaller sensor signal or to &H7FFF in case of discrepancies.
 If the undisturbed process value is in the normal range (here: lower than 90),
the output of the evaluation logic is 1 (i.e., no trigger command).
 If the undisturbed process value exceeds the limit (here: greater than or equal to 90),
 If the F-AI reports a channel fault, the output of the evaluation logic is 0

 Create an F_CH_AI F-channel driver for the analog input signal and connect it
to the symbol on the address with the lowest channel number (e.g.
F_TAG1001_X to EW512). Use a limit block (F_LIM_HL or F_LIM_LL) to

– Negated value of the channel fault output (QBAD) from the F-channel driver

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5 Hardware configuration and wiring of two sensors (1oo2) with redundant F-AI and evaluation
in the modules (2oo2)

sensors (1oo2) with redundant F-AI and
evaluation in the modules (2oo2)
To increase the availability of the system, an architecture with two sensors can be
realized with redundant modules in order to achieve the required SIL.
Each F-AI performs a 1oo2 evaluation of the two sensors and the CPU performs a
2oo2 evaluation of the signals.
level of SIL3. However, to be SIL-compliant, the entire safety function – including
the field devices – must be assessed according to IEC 61508/IEC 61511.
In this architecture, two sensors are wired to a redundant F-AI pair. A block
diagram can be found in Fig. 5-1.
The first sensor in the diagram is wired to channel 0 and the second sensor is
wired to channel 3 of both modules. The modules are configured as redundant
modules in HW Config. Each F-AI performs a 1oo2 evaluation of the two sensors.
Only one analog F-channel driver is required. The F-channel driver chooses from
the incoming analog signals.
Fig. 5-1: 1oo2 evaluation in the redundant F-AI architecture

F-AI
Ch 0..5
Sensor 1
0
Evalution
1002
Sensor 2 CPU
3
Voting
F_CH_AI Logic
F-AI
Ch 0..5
0
Evalution
1002
The hardware configuration according to Fig. 5-1 is suitable for achieving SIL3.

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function possible?
Sensor 1 Sensor 2 F-AI 1 F-AI 2
No No No X Yes (not required)
No No X No Yes (not required)
X Yes X X Yes
Yes X X X Yes
X X Yes Yes Yes
5.1 PFD calculation


formula:

4
The PFDSensor for one 1oo2 sensor is calculated using the following formula:
4

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5.2 Wiring
An example for the 1oo2 evaluation scheme with evaluation in the F-AI and
redundant F-AI is illustrated in Fig. 5-2.
The first sensor is wired to channel 0 (terminals 3, 4, 5) and the second sensor is
wired to channel 3 (terminals 12, 13, 14) of both F-AIs.
Please note that this architecture also requires two Zener diodes for each sensor.
The first Zener diode has an avalanche voltage of 6.2 V and the second one has
an avalanche voltage of 5.6 V. Another two diodes are also used for decoupling the
voltage supply. The diodes and Zener diodes are needed in case an F-AI is out of
service (e.g. module failure, routine maintenance, etc.).
Fig. 5-2: 1oo2 evaluation in the redundant F-AI , 2-channel, 2-wire transmitter, internal
supply
2-Wire
Current
Transmitter
2-Wire
Current
Transmitter


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Zener diodes.
Fig. 5-3: MTA


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For the 1oo2 evaluation scheme with evaluation in the redundant F-AI, the F-AIs
are configured in STEP 7 HW Config.
Fig. 5-4 illustrates an example of a hardware configuration. An ET 200M with
PROFIBUS address 3 and a second ET 200M with PROFIBUS address 4 are
used. Each ET 200M contains one F-AI in slot 4. For further information on
hardware configuration, see \4\ in the "Links and Literature" chapter.
Fig. 5-4: 1oo2 evaluation in the redundant F-AI HW Config

The two F-AIs must be configured as a redundant pair in the HW Config. Each of
the F-AI redundancy settings can be accessed through the object properties of the
F-AIs.
settings are made with PROFIBUS address 3 using the F-AI in the ET 200M.
The interface of the redundancy settings is shown in Fig. 5-5 and the settings are
summarized in Table 5-2.

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Fig. 5-5: 1oo2 evaluation in the redundant F-AI, redundancy parameters

Table 5-2: 1oo2 evaluation in the redundant F-AI, redundancy parameters

or permissible
value range
Redundancy Shows whether the F-AI is acting as part of 2 modules
a redundant pair or not.
Remark:
to 2 modules.
Redundant module Used to select the redundant partner
module.
Note The parameter names and configuration window may differ from those in this
After adjusting the redundancy settings, the remaining hardware parameters for the
redundant F-AI can be set as described at the end of section 4.3. The settings are
applied automatically to the redundant partner.

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Although this evaluation scheme uses redundant F-AIs, only one F_CH_AI F-
channel driver is needed in the logic configuration. The F-channel driver can be
added and configured automatically from the SIMATIC Safety Matrix or manually
using the STEP 7 CFC Editor. In both cases, the F-channel driver must be
connected to the analog sensor signal of the F-AI with the lowest I/O address.
The logic is compiled when the F-channel driver is configured and the evaluation
logic is complete. If the option to generate module drivers is activated during
compilation, the corresponding F_PS_12 module drivers are automatically added
to the logic and configured during the compilation. The F-channel driver selects the
valid signal and, in the event of a fault, switches to the signal of the redundant
module.
After the 1oo2 evaluation is configured in the F-AI, the CPU logic for reading a
single sensor can be implemented. One implementation method is to use the
SIMATIC Safety Matrix Engineering Tool (for further relevant information, see \5\ in
the "Links and Literature" chapter).
The actual evaluation logic for the 1oo2 evaluation scheme with redundant F-AI is
the same as that described in the Section 4.4.1 (Configuring with Safety Matrix).

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As an alternative to using the Safety Matrix Tool, you can implement the CPU logic for
reading the input signal by means of the STEP 7 CFC Editor. The evaluation logic can
be generated in the CFC Editor after the F-AI performs the 1oo2 evaluation.
Logic without channel fault evaluation (1oo2 in the F-AI)

Fig. 5-6 illustrates a sample logic for reading a single input signal in the CFC
Editor, which does not take a channel fault into account. Please note that this

below the limit.
signals.

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 The redundant F-AI evaluates the two sensor signals and sends a value to the
CPU for further processing. This value reflects the value of one of the sensors.
Depending on how the "Unit value" parameter is set in the hardware
configuration, the value corresponds to either the larger or the smaller one or
to &H7FFF in case of a discrepancy.
 The F_CH_AI F-channel driver evaluates the two sensor signals and sends a
value to the logic for further processing.
 If the process value is in the normal range (here: lower than 90), the output of
the evaluation logic is 1 (i.e., no trigger command).
 If the process value exceeds the limit (here: greater than or equal to 90), the
output of the evaluation logic is 0 (i.e., trigger command).
To create the configuration, create an F_CH_AI F-channel driver for the analog
input signal and connect it to the symbol on the F-AI with the lowest address and
with the lowest channel number (e.g. F_TAG1001_X to EW512). Use a limit block
(F_LIM_HL or F_LIM_LL) to compare the signal with the tripping limit value.

Fig. 5-7 illustrates a sample logic created in the CFC Editor for reading an input
signal that takes a channel fault into account. Please note that this example starts
from a MAX limit and that the output of the evaluation logic is switched off to reach
the safe state (Normal State = 1, Safe State = 0).
Fig. 5-7: CFC logic – Channel fault evaluation
signals.

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 The F-AI evaluates the two sensor signals and sends a value to the CPU for
further processing. This value reflects the value of one of the sensors.
Depending on how the "Unit value" parameter is set in the hardware
configuration, the value corresponds to either the larger or the smaller one or
to &H7FFF in case of discrepancy.
 If the undisturbed process value is in the normal range (here: lower than 90),
the output of the evaluation logic is 1 (i.e., no trigger command).
 If the undisturbed process value exceeds the limit (here: greater than or equal
to 90), the output of the evaluation logic is 0 (i.e., trigger command).
 If both F_AIs report a channel fault, the output of the evaluation logic is 0

 Create an F_CH_AI F-channel driver for the analog input signal and connect it to
the symbol on the F-AI with the lowest address and with the lowest channel number

Negated value of the channel fault output (QBAD) from the F-channel driver

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6 Hardware configuration and wiring of two sensors (1oo2) and evaluation in the user program

sensors (1oo2) and evaluation in the user
program
The two-sensor or 1oo2 evaluation scheme refers to applications that need two
sensors to achieve the required safety integrity level. 1oo2 evaluation means that
only one of two sensors must fail to trigger the safety function.
In contrast to the evaluation in the F-AI, in this case the evaluation is carried out in
the user program in order to have the visibility of both signals and their quality in
the application logic - which allows more flexible evaluation schemes
(e.g. 1oo2D or 2oo2).
Note This architecture can achieve the safety integrity level SIL3. However, to be SIL-
compliant, the entire safety function – including the field devices – must be
assessed according to IEC 61508/IEC 61511.
For this scheme, one can choose between two design variants, which differ in their
PFD and availability.
 Option 1: with one module

Both sensors are wired to one F-AI as illustrated in Fig. 6-1. In this diagram,
one sensor is wired to channel 0 and the other to channel 3 of the F-AI.
 Option 2: with two modules
Both sensors are wired to two F-AIs as illustrated in Fig. 6-2. In this diagram,
one sensor is wired to channel 0 of the first F-AI whereas the second sensor to
channel 0 of the second F-AI.

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6.1 Option 1: with one module

Fig. 6-1: 1oo2 evaluation in the user program
F -AI
Ch 0..5
Sensor 1
0
CPU
Sensor 2
3
F _CH _ AI 1oo 2
Voting
Logic

Failed component detected? Tripping of the
safety function possible?
Sensor 1 Sensor 2 F-AI
X X Yes Yes
X Yes X Yes
Yes X X Yes

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6.1.1 PFD calculation (option 1)


formula:

5
6.2 Option 2: with two modules

Fig. 6-2: 1oo2 evaluation in the user program

F-AI
Ch 0..5
Sensor 1
0
CPU
F_CH_AI 1oo2
Voting
Logic
F-AI
Ch 0..5
Sensor 2
0
The hardware configuration according to Figure 4-2 is suitable for achieving SIL3.
5

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function possible?
No No No No Yes (not required)
X X X Yes Yes
X X Yes X Yes
X Yes X X Yes
Yes X X X Yes
6.2.1 PFD calculation (option 2)


formula:
PFDIn = PFD1oo2 + PFDCPU

6
The PFD for one 1oo2 input circuit is calculated using the following formula:
With:
6

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6.3 Wiring
In the 1oo2 evaluation scheme, the sensors can be powered from the F-AI or an
external voltage source.
The following diagrams show the wiring for 2-wire and 4-wire transmitters powered
from the F-AI or an external voltage source.
The transmitters in the following diagrams are wired to two channels of an
F-AI. The first sensor is wired to channel 0 (terminals 3, 4, 5 - jumper to 1M) and
the second sensor to channel 3 (terminals 12, 13, 14 - jumper to 1M).
The F-AI is supplied with power via 1L+/1M (terminals 1 and 2), and the sensors
via Vs0... Vs5 (terminal 3, 6, 9, 12, 15, 18), depending on the channel, or from an
external voltage source.
Fig. 6-3: 1oo2 evaluation in the user program, 2-wire transmitter, 2-channel connection,
internal supply
2-Wire
Current
Transmitter
2-Wire
Current
Transmitter
Process variable is acquired with

two mechanically separate
sensors.

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internal supply
SM336;
AI 6x 0/4...20mA HART
L+ 1
1L+
M 2
1M
Vs0 3
CH0 M0+ 4 4-Wire
+
M0- 5
Current
- Transmitter
Vs1 6
CH1 M1+ 7
M1- 8
Vs2 9
CH2 M2+ 10
+ 4-Wire
Current
M2- 11 - Transmitter
Vs3 12
CH3 M3+ 13
M3- 14
Vs4 15
CH4 M4+ 16
M4- 17
Vs5 18
CH5 M5+ 19
M5- 20

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The
Fig. 6-5 shows an example where an external voltage source with 2-wire
transmitters is used:
external supply
2-Wire
Current
Transmitter
recommended
2-Wire
Current
Transmitter

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The Fig. 6-6 illustrates an external voltage source with a 4-wire transmitter.
external supply
4-Wire
Current
Transmitter
recommended
4-Wire
Current
Transmitter

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Zener diodes.
Fig. 6-7: MTA


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To configure, select the F-AI in the hardware catalog off the HW Config and insert it
into an existing ET 200M station. Select meaningful icon names for the channels in
order to facilitate later configuration.
Fig. 6-8 illustrates an example of a hardware configuration with one F-AI. The two
sensor signals in this example are wired to the first two channels of the F-AI. For
further information on hardware configuration, see \4\ in the "Links and Literature"
chapter.
Please note that you do not need to perform any particular hardware configuration
to use an F-AI MTA.
Fig. 6-8 1oo2 Evaluation in the user program, Symbol editing

the F-AI added (see Fig. 6-9 and Fig. 6-10).

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Fig. 6-9: 1oo2 Evaluation in the user program, Parameters – part 1

Fig. 6-10: 1oo2 Evaluation in the user program, Parameters – part 2

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Table 6-3: 1oo2 evaluation in the user program. Hardware configuration parameters
or permissible
value range
F-parameters
1111111110
F_monitoring Monitoring time for safety-related 0...65535ms
time communication between the CPU and the Default 2500ms
(ms) F-AI.
calculate
Module parameters
Diagnostic interrupt A diagnostic interrupt is triggered by various Release / lock
error events that can be detected by the
module. These events are then reported to
the CPU.
Remark:
If the diagnostic interrupt is released at the
module level, individual diagnostic events

must be also activated at the channel level.
Behavior after channel Passivate the entire module/ passivate the Module/
faults channel. Channel
Remark:
HART_Gate Acts as a fail-safe "main switch" across the Off/
modules. On/
HART communication is blocked with "Off". switchable
HART communication is enabled with "On".
Interference frequency Selection for matching the integration time 50/60 Hz
– 20 ms at 50 Hz
– 16.66 ms at 60 Hz
– Deactivated
– 1oo1 (1v1)
– 1oo21 (2v2)
– Tolerance range
– Unit value
Measuring range Measuring range selection for the channel. 0...20 mA
4...20 mA

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or permissible
value range
F wire break detection Select whether or not to enable wire break Release / lock
monitoring for the channel.
Smoothing Number of measuring cycles through which 1, 4, 16, 64
smoothing is carried out.

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After the sensor signals have been added to the hardware configuration, the 1oo2
evaluation logic can be implemented in the user program. One option is to use the
Fig. 6-11 illustrates how a cause for the 1oo2 evaluation of the sensor signals is
configured in the matrix. The following settings must be used:
 2 inputs
 Function type: OR (1oo2)
 Tag 1 and Tag 2 must be entered and should correspond to the symbolic I/O
name of the encoder (e.g. F_TAG1001_X and F_TAG1002_X). The input can
be added by selecting the signal from the symbol table. To do this, use the
"I/O" button.
The cause is configured with the OR (1oo2) function type. If at least one encoder is
released for triggering, the cause activates and triggers the corresponding effect(s).
Fig. 6-11: 1oo2 evaluation in the user program (Safety Matrix – Configure)

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– Limit value
– Pre-alarm
– Hysteresis
– Delta
– Units:
Fig. 6-12: 1oo2 evaluation in the user program (Safety Matrix – Analog parameter)
Additional attributes are available (e.g. time delay and bypass option), depending
on the process application.
One configuration option highlighted in Fig. 6-13 is the shutdown behavior in case
of a channel fault. If this option is activated, a channel fault will act as a violation of
the limit on a sensor input. in the case of OR (1oo2), if there is a channel error and
the option is enabled, the cause activates and triggers the corresponding effect(s).

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Fig. 6-13: 1oo2 evaluation in the user program (Safety Matrix – Options)
As an alternative to using the Safety Matrix Tool, you can implement the 1oo2
evaluation logic for the input signals by means of the STEP 7 CFC Editor. After the
sensor signals have been added to the hardware configuration, the 1oo2
evaluation logic can be implemented with the CFC Editor.
Please note that by using the appropriate logic blocks, you can also implement a
2oo2 evaluation in the user program.

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Fig. 6-14 illustrates an example logic created in the CFC Editor for 1oo2 evaluation that
does not take channel faults into account.
Please note that this example starts from a MAX limit and that the output of the evaluation
logic is switched off to reach the safe state (Normal State = 1, Safe State = 0).

below the limit.

 If both analog sensors send a process value in the normal range
(here: a process value lower than 90), the output of the evaluation logic is 1
(i.e., no trigger command).
 If the process value of one or both analog sensors exceeds the limit
(here: a process value greater than or equal to 90), the output of the evaluation
logic is 0 (i.e., trigger command).

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 Create an F_CH_AI channel driver for the first analog sensor and connect it to
the address of the sensor connected to the F-AI (e.g. F_TAG1001_X to
 Create an F_CH_AI channel driver for the second analog
sensor and connect it to the address of the sensor connected to the F-AI
 Create an AND operation for the negated output values of the limit blocks
(QHN or QLN).
Fig. 6-15 illustrates an example logic created in the CFC Editor for 1oo2 evaluation
that takes channel faults into account.
Please note that this example starts from a MAX limit and that the output of the
evaluation logic is switched off to reach the safe state (Normal State = 1, Safe
State = 0).

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 If both analog sensors send a process value in the normal range without
channel fault (here: a process value lower than 90), the output of the
evaluation logic is 1 (i.e., no trigger command).
(here: a process value greater than or equal to 90) and the sensor does not report a
channel fault, the output of the evaluation logic is 0 (i.e., trigger command).
 If at least one of the two analog sensors reports a channel fault, the output of
the evaluation logic is 0 (i.e., trigger command).

 Create an F_CH_AI F-channel driver for the first analog sensor and connect it to
the address of the sensor connected to the F-AI (e.g. F_TAG1001_X to EW512).
Use a limit block (F_LIM_HL or F_LIM_LL) to compare the signal with the tripping
limit value.
 Create an F_CH_AI F-channel driver for the second analog sensor and
connect it to the address of the sensor connected to the F-AI

 Create an AND operation of the 3 outputs for the following logic in order to
generate the signal for the trigger command:
– Use the negated output of the first F-channel driver's limit block (QHN or QLM).
– Use the negated output of the second F-channel driver's limit block (QHN or QLM).
– Use an OR block to connect the QBAD outputs of both F-channel drivers
and use the output signal (OUTN) of the OR block.

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7 Hardware configuration and wiring of two sensors (1oo2) with redundant F-AI (2oo2) and
evaluation in the user program

sensors (1oo2) with redundant F-AI (2oo2)
and evaluation in the user program
To increase the availability of the system, an architecture that requires two sensors
can be realized with redundant modules in order to achieve the required SIL. Both
evaluations are carried out in the user program.
levels of SIL3. However, to be SIL-compliant, the entire safety function –
including the field devices – must be assessed according to IEC 61508/IEC
61511.
In this architecture, two sensors are wired to a pair of redundant F-AIs. A block
diagram can be found in Fig. 7-1.
In the diagram, the first sensor on Channel 0 is wired to both F-AIs. The second
sensor is wired to Channel 1 of both F-AIs. The F-AIs are configured as redundant
modules in the HW Config. Only one analog input channel driver block per sensor
is required. The driver block selects a signal from the incoming signals of the
redundant F-AI.
Fig. 7-1: 1oo2 evaluation in the user program – redundant F-AIs

F-AI
Ch 0..5
Sensor 1
0
CPU
1
1oo2
F_CH_AI
Voting
Logic
F-AI
Ch 0..5
Sensor 2
1

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function possible?
No No No X Yes (not required)
No No X No Yes (not required)
Yes X X X Yes
X Yes X X Yes
X X Yes Yes Yes
Note The redundancy of the I/O modules does not increase the safety integrity level
7.1 PFD calculation



formula:

7
7

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7.2 Wiring
A simplified example of the 2(1oo2) evaluation scheme with evaluation in the user
program and redundant F-AI is illustrated in Fig. 7-2. The first sensor is wired to
channel 0 (terminals 3, 4, 5) of both F-AIs and the second sensor is wired to
channel 1 (terminals 6, 7, 8) of both F-AIs.
Please note that this architecture also requires two Zener diodes for each sensor.
The first Zener diode has an avalanche voltage of 6.2 V and the second one has a
avalanche voltage of 5.6V. Another two diodes are also used for decoupling the
voltage supply. The diodes and Zener diodes are needed in case one of the F-AIs
is out of service (e.g. module failure, routine maintenance, etc.).
Fig. 7-2: 1oo2 evaluation in the user program, redundant F-AI, 2-wire, 2-channel transmitter,
internal supply
2-Wire
Current
Transmitter
2-Wire
Current
Transmitter


Zener diodes.

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Fig. 7-3: MTA


For the 2(1oo2) evaluation scheme with evaluation in the user program and
redundant F-AIs, the F-AIs themselves are configured in the STEP 7 HW Config.
For further information on hardware configuration, see \4\ in the
"Links and Literature" chapter.
Fig. 7-4 illustrates a hardware configuration as an example.
In this example, there is an ET 200M (with PROFIBUS connection IM153-2) with
PROFIBUS address 3 and a second ET 200M with PROFIBUS address 4. Each
ET 200M contains one F-AI in slot 4.
For further information on hardware configuration, see \4\ in the
"Links and Literature" chapter.

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Fig. 7-4: 1oo2 evaluation in the user program – redundant F-AI

hardware configuration plan
F-AIs.
For further information on hardware, see \4\ in the "Links and Literature" chapter.
In Fig. 7-4, the redundancy settings are made with PROFIBUS address 3 using the
F-AI in the ET 200M. The settings are summarized in Table 7-2.

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Fig. 7-5: 1oo2 evaluation in the user program – redundant F-AI

Redundancy parameters
Table 7-2: 2 1oo2 evaluation in the user program – redundant F-AI - Redundancy
parameters
Parameter Description / Recommendations Desired setting or
permissible value
range
Redundancy Shows whether the F-AI is acting as part of a Two (2)
redundant pair or not. modules
Remark:
to 2 modules.
Redundant Used for selecting the redundant partner
module module.
redundant module.

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Although this evaluation scheme uses redundant F-AIs, only two F_CH_AI
F-channel driver blocks are needed in the logic configuration (one F-channel driver
for each of the two sensors). The F-channel drivers can be added and configured
automatically from the SIMATIC Safety Matrix or manually using the STEP 7 CFC
Editor. In both cases, the drivers must be connected to the analog sensor signal of
the F-AI with the lowest I/O address.
The logic is compiled when the F-channel drivers are configured and the evaluation
logic is complete.
If the option to generate module drivers is activated during compilation, the
corresponding F_PS_12 module drivers are automatically added to the logic and
configured during the compilation. The F-channel driver selects the valid signal
After the sensor signals have been added to the hardware configuration, the 1oo2
evaluation logic can be implemented in the user program. One option is to use the
The actual evaluation logic of the 2(1oo2) evaluation scheme with evaluation in the
user program and redundant F-AI is identical to the one described in
Section 6.5.1 (Configuring with Safety Matrix).

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evaluation logic for the input signals by means of the STEP 7 CFC Editor. After the
evaluation logic can be implemented with the CFC Editor.
Please note that by using the appropriate
logic blocks, you can also implement a 2oo2 evaluation in the user program.
Fig. 6-14 illustrates an example logic created in the CFC Editor for 1oo2 evaluation
that does not take channel faults into account.
Please note that this example starts from a MAX limit and that the output of the
evaluation logic is switched off to reach the safe state (Normal State = 1, Safe
State = 0).

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below the limit.

 If both analog sensors send a process value in the normal range

the symbol on the F-AI with the lowest address (e.g. F_TAG1001_X to
 Create an F_CH_AI channel driver for the second analog
sensor and connect it to the symbol on the F-AI with the lowest address
 Create an AND operation for the negated output values of the limit blocks
(QHN or QLN).

Figure 7-7 illustrates an example logic created in the CFC Editor for 1oo2 evaluation
that takes a channel fault into account.
Please note that this example starts from a MAX limit and that the output of the evaluation
logic is switched off to reach the safe state (Normal State = 1, Safe State = 0).

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Figure 7-7: CFC logic – With channel fault evaluation

The example logic in Figure 7-7 works as follows:

 If both analog sensors send a process value in the normal range without
channel fault (here: a process value lower than 90), the output of the
(here: a process value greater than or equal to 90) and the sensor does not report a
channel fault, the output of the evaluation logic is 0 (i.e., trigger command).
 If at least one of the two analog sensors reports a channel fault, the output of
the evaluation logic is 0 (i.e., trigger command).

the symbol on the F-AI with the lowest address (e.g. F_TAG1001_X to
 Create an F_CH_AI channel driver for the second analog sensor and connect it
to the symbol on the F-AI with the lowest address (e.g. F_TAG1002_X to
 Create an AND operation of the 3 outputs for the following logic in order to
generate the signal for the trigger command:
– Use the negated output of the limit block (QHN or QLM) of the first channel
driver block.
– Use the negated output of the limit block (QHN or QLM) of the second
channel driver block.
– Use an OR block to connect the QBAD outputs of both channel driver
blocks and use the output signal (OUTN) of the OR block.

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8 Hardware configuration and wiring of three sensors and three F-AIs (2oo3) with evaluation in
the user program
8 Hardware configuration and wiring of three

sensors and three F-AIs (2oo3) with
The three-sensors (or 2oo3 evaluation scheme) refers to applications that require
two sensors to achieve the Safety Integrity Level and a third sensor for higher
availability. 2oo3 evaluation means that two out of three sensors have to trigger.
Note The I/O modules in this architecture are certified for the safety integrity level
SIL3. However, to be SIL-compliant, the entire safety function – including the
field devices – must be assessed according to IEC 61508/IEC 61511.
The 2oo3 base architecture with evaluation in the user program uses three sensors
and three F-AI. A block diagram can be found in Fig. 8-1. In the diagram, each
sensor on Channel 0 is wired to one F-AI. In this example, the F-AI are integrated
into an ET 200M.
Please note that due to the system flexibility, there could be also other
architectures that differ to the variant described in terms of the availability of the
modules and ET 200M racks, e.g.:
 Low availability:
All three sensors are connected to one module.
 Similar availability of the modules:
All three sensors are connected to two mutually redundant modules. The two
modules are integrated in the same ET 200M rack.
 Higher availability of modules and ET 200M racks:
All three sensors are connected to two mutually redundant modules. The two
modules are integrated in various ET 200M racks (see Chapter 9).
 Higher availability of modules and ET 200M racks:
Each sensor is connected to a module. The modules are integrated in various
ET 200M racks.

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the user program
Fig. 8-1: 2oo3 – architecture

F-AI
Ch 0..5
Sensor 1
0
F-AI
Ch 0..5
Sensor 2 CPU
0
F_CH_AI 2oo3
Voting
Logic
F-AI
Ch 0..5
Sensor 3
0

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the user program
function possible?
Sensor Sensor Sensor F-AI 1 F-AI 2 F-AI 3
1 2 3
Yes No No Yes No No Yes (not required)
No Yes No Yes
No No Yes Yes
No Yes No Yes No No Yes
No Yes No Yes (not required)
No No Yes Yes
No No Yes Yes No No Yes
No Yes No Yes
No No Yes Yes (not required)
X Yes Yes X X X Yes
Yes X Yes
Yes Yes X
X X X X Yes Yes
Yes X Yes
Yes Yes X
8.1 PFD calculation


formula:
PFDIn = PFD2oo3 + PFDCPU

8
The PFD value for one 2oo3 input circuit is calculated using the following formula:
With:
8

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the user program
8.2 Wiring
In the 2oo3 evaluation scheme, the F-AI or an external voltage source can supply
the sensors with voltage.
Fig. 8-2 illustrates a wiring example for 2-wire transmitters and
In both diagrams, each transmitter on Channel 0 is wired to one F-AI.
Fig. 8-2: 2oo3, evaluation in the user program with 3 F-AIs and 3 transmitters, 2-wire,
internal supply.
Process variable
is acquired with
mechanically 2-Wire 2-Wire 2-Wire
separate sensors. Current Current Current
Transmitter Transmitter Transmitter

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the user program
Fig. 8-3: 2oo3 evaluation in the user program with 3 F-AIs and 3 transmitters, 4-wire, internal
supply.
SM336;
1L+
L+ 1
M
M 2
Vs0 3
CH0 M0+ 4 4-Wire-

+ Current-
M0- 5 - Transmitter
Vs1 6
CH1 M1+ 7
SM336;
M1- 8 AI 6x 0/4...20mA HART
L+ 1 1L+
Vs2 9
M 2 M
CH2 M2+ 10
Vs0 3
CH0 M0+ 4-Wire-

4
M2- 11
+ Current-
M0- 5 - Transmitter
Vs3 12
Vs1 6
CH3 M3+ 13
CH1 M1+ 7
M3- 14
SM336;
M1- 8 AI 6x 0/4...20mA HART
Vs4 15 1L+
L+ 1
Vs2 9
CH4 M4+ 16
M 2 M
CH2 M2+ 10
M4- 17
Vs0 3
Vs5 18 CH0 M0+ 4 4-Wire-
M2- 11
CH5 M5+
+ Current-
19
Vs3 12
M0- 5 - Transmitter
M5- 20
Vs1 6
CH3 M3+ 13
CH1 M1+ 7
M3- 14
M1- 8
Vs4 15
Vs2 9
CH4 M4+ 16
CH2 M2+ 10
M4- 17
Vs5 18
M2- 11
CH5 M5+ 19
Vs3 12
M5- 20
CH3 M3+ 13
M3- 14
Vs4 15
CH4 M4+ 16
M4- 17
Vs5 18
CH5 M5+ 19
M5- 20

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the user program
Fig. 8-4 illustrates a wiring example for 2-wire transmitters with one external
voltage source and Fig. 8-5 shows a wiring example for 4-wire transmitters with
one external voltage source.
In both diagrams, each transmitter on Channel 0 is wired to one F-AI.
Fig. 8-4: 2oo3 evaluation in the user program with 3 F-AIs and 3 transmitters, 2-wire,
external supply.
2-Wire- 2-Wire- 2-Wire-

M Current- M Current- M Current-
Transmitter Transmitter Transmitter
2L+ 2L+ 2L+
+ - + - + -
SM336; SM336; SM336;

AI 6x 0/4...20mA HART AI 6x 0/4...20mA HART AI 6x 0/4...20mA HART
1L+ 1L+ 1L+
L+ 1 L+ 1 L+ 1
M
M 2 M 2 M M 2 M
Vs0 3 Vs0 3 Vs0 3
CH0 M0+ CH0 M0+ CH0 M0+

4 4 4
M0- 5 M0- 5 M0- 5
Vs1 6 Vs1 6 Vs1 6
CH1 M1+ 7 CH1 M1+ 7 CH1 M1+ 7

M1- 8 M1- 8 M1- 8
Vs2 9 Vs2 9 Vs2 9
CH2 M2+ 10 CH2 M2+ 10 CH2 M2+ 10
M2- 11 M2- 11 M2- 11
Vs3 12 Vs3 12 Vs3 12
CH3 M3+ 13 CH3 M3+ 13 CH3 M3+ 13
M3- 14 M3- 14 M3- 14
Vs4 15 Vs4 15 Vs4 15
CH4 M4+ 16 CH4 M4+ 16 CH4 M4+ 16
M4- 17 M4- 17 M4- 17
Vs5 18 Vs5 18 Vs5 18
CH5 M5+ 19 CH5 M5+ 19 CH5 M5+ 19
M5- 20 M5- 20 M5- 20

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the user program
Fig. 8-5: 2oo3 evaluation in the user program with 3 F-AIs and 3 transmitters, 4-wire,
external supply.
SM336;
1L+
L+ 1
M
M 2
Vs0 3
CH0 M0+ 4 4-Wire- 2L+

+
Current-
M0- 5
- Sensor M
Vs1 6
CH1 M1+ 7
SM336;
M1- 8 AI 6x 0/4...20mA HART
L+ 1 1L+
Vs2 9
M 2 M
CH2 M2+ 10
Vs0 3
CH0 M0+ 4 4-Wire- 2L+

M2- 11 +
Current-
M0- 5
Vs3 12 - Sensor M
Vs1 6
CH3 M3+ 13
CH1 M1+ 7
M3- 14
SM336;
M1- 8 AI 6x 0/4...20mA HART
Vs4 15 1L+
L+ 1
Vs2 9
CH4 M4+ 16
M 2 M
CH2 M2+ 10 2L+
M4- 17
Vs0 3
Vs5 18 CH0
11
M0+ 4 4-Wire-
M2- +
CH5 M5+ 19 Current-
M0- 5
Vs3 12 - Sensor
M5- 20
Vs1 6
CH3 M3+ 13
M
CH1 M1+ 7
M3- 14
M1- 8
Vs4 15
Vs2 9
CH4 M4+ 16
CH2 M2+ 10
M4- 17
Vs5 18
M2- 11
CH5 M5+ 19
Vs3 12
M5- 20
CH3 M3+ 13
M3- 14
Vs4 15
CH4 M4+ 16
M4- 17
Vs5 18
CH5 M5+ 19
M5- 20

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the user program

The three F-AIs required for the 2oo3 evaluation scheme are configured in STEP 7
HW Config. For configuration, select the F-AI in the STEP 7 hardware catalog. Add
this to the existing hardware configuration once. Configure the channels used and
assign meaningful symbol names.
Fig. 8-6: 2oo3 evaluation in the user program – symbol editing

Fig. 8-6 shows an example of a hardware configuration with three F-AIs. In this
example, the ET 200M (IM153-2) contains an F-AI in each of slots 4, 5 and 6. Each
of the three sensor signals is wired to the first channel of an F-AI. For further
information on hardware configuration, see \4\ in the "Links and Literature" chapter.
The parameters themselves are summarized in Table 8-1.

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the user program
Fig. 8-7: 2oo3 evaluation in the user program – Parameters

Table 8-1: 2oo3 evaluation in the user program – Parameters

or permissible
value range
F-parameters
F_destination_address PROFIsafe address of the 1-1022
1111111110
F_monitoring_time Monitoring time for safety-related 0...65535 ms

(ms) communication between the CPU and the Default 2500 ms
F-AI.
Remark:
A worksheet is available on the Siemens
Support website to help users calculate

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the user program

or permissible
value range
Module parameters
Diagnostic interrupt A diagnostic interrupt is triggered by various Release / lock
error events that can be detected by the
module. These events are then reported to
the CPU.
Remark:
If the diagnostic interrupt is released at the
module level, individual diagnostic events
must be also activated at the channel level.
Behavior after Passivate the entire module/ passivate the Module/
channel faults channel. Channel
Remark:
HART_Gate Acts as a fail-safe "main switch" across the Off/
modules. On/
HART communication is blocked with "Off". switchable
HART communication is enabled with "On".

Interference Selection for matching the integration time 50/60 Hz
frequency of the ADC to the network used.
suppression The integration time is:
(Hz) – 20 ms at 50 Hz
– 16.66 ms at 60 Hz
– Deactivated
– 1oo1 (1v1)
– 1oo2 (2v2)
– Tolerance range
– Unit value
Measuring range Measuring range selection for the channel. 0...20 mA
4...20 mA
F_wire-break Select whether or not to enable wire break Release / lock
detection monitoring for the channel.
Smoothing Number of measuring cycles through which 1, 4, 16, 64

smoothing is carried out.

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the user program

After the three sensor signals have been added to the hardware configuration, the
2oo3 evaluation logic can be implemented in the user program. One option is to
use the SIMATIC Safety Matrix Engineering Tool (for further relevant information,
see \5\ in the "Links and Literature" chapter).
Figure 8-8 illustrates how a cause is configured in the Matrix for 2oo3 evaluation.
The following settings must be used:
 3 inputs
 Function type: Majority Evaluation (2oo3 evaluation)
 Tag 1, Tag 2 and Tag 3 must be entered and should correspond to the
symbolic I/O name of the encoder (e.g. F_TAG1001_X, F_TAG1002_X and
F_TAG 1003_X). The input can be added by selecting the signal from the
symbol table. To do this, use the "I/O" button.
The cause is configured with a Majority Evaluation (2oo3 evaluation) function type.
If at least two of the three encoders are released for triggering, the cause activates
and triggers the corresponding effect(s). Please note that it is also possible to
configure other evaluation architectures – 1oo3 (OR) or 3oo3 (AND) – in the
"Function Type" field.
Figure 8-8: Safety Matrix – Configure

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the user program
As shown in Fig. 8-9, there are additional analog parameters that must be set for
the cause:
– Limit value
– Pre-alarm
– Hysteresis
– Delta
– Unit of measurement
Exceeding the delta value is reported. It is not considered a shutdown criterion.

Additional attributes are available (e.g. time delay and bypass option), depending
on the process application.

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the user program
One configuration option highlighted in Fig. 8-10 is the shutdown behavior in case
of a channel fault.
If this option is activated, a channel fault at one of the sensor inputs is evaluated as
a trigger signal. In a Majority Evaluation (2oo3) (if this option is enabled), the cause
is activated and the relevant effect(s) are triggered on the occurrence of two
channel faults, or a channel fault and a channel limit violation.


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the user program
evaluation logic for the CPU by means of the STEP 7 CFC Editor. After the three
evaluation logic can be made with the CFC Editor.

The logic corresponds to the Safety Matrix configuration, in which the function
"Trip on bad quality" is not enabled. The input signals are not monitored for a
maximum delta.
Figure 8-11 shows an example logic for 2oo3 evaluation in the CFC Editor, which
does not take channel faults into account. Please note that this example starts from
a MAX limit and that the output of the evaluation logic is switched off to reach the
safe state
(Normal State = 1, Safe State = 0).

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the user program
Figure 8-11: CFC Logic – Without channel fault evaluation

In the logic shown (SUBS_ON = 0 on the F-channel driver), the last valid value
is used in case of error. It is not possible to predict whether this value is above or
below the limit.

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the user program
Figure 8-11 works as follows:

 If at least two of the three analog sensors report a normal value
 If at least two analog sensors report an upper limit violation

 Create an F_CH_AI F-channel driver for the first analog sensor and connect the
corresponding I/O signal to the block. Use a limit block (F_LIM_HL or F_LIM_LL)
to compare the signal with the tripping limit value.
connect the corresponding I/O signal to the block. Use a limit block
 Create an F_CH_AI F-channel driver for the third analog sensor and connect the
 Connect the negated outputs of the limit value blocks (QHN or QLN) with the
inputs of an F_2OUT3 block in order to generate the signal for the trigger
command.

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the user program

The logic corresponds to the Safety Matrix configuration, in which the function "Trip
on bad quality" is enabled. The input signals are not monitored for a maximum delta.
Fig. 8-12 shows an example logic for 2oo3 evaluation in the CFC Editor, which
takes channel faults into account. Please note that this example starts from a MAX
limit and that the output of the evaluation logic is switched off to reach the safe
state (Normal State = 1, Safe State = 0).


 If at least two of the three analog sensors report a normal value without
channel faults (here: a process value lower than 90), the output of the
 If two or more analog sensors report an upper limit violation without channel
fault (here: a process value greater than or equal to 90), the output of the
evaluation logic is 0 (i.e., trigger command).
 If two or more analog sensors report a channel fault, the output of the
 If one sensor reports a channel fault and the other two sensors do not report a
channel fault, only the values of the sensors without channel faults are used for
the evaluation logic.

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the user program

 Create an F_CH_AI channel driver for the first analog sensor and connect the
 Create an F_CH_AI channel driver for the second analog sensor and connect
the corresponding I/O signal to the block. Use a limit block (F_LIM_HL or
F_LIM_LL) to compare the signal with the tripping limit value.
 Create an F_CH_AI channel driver for the third analog sensor and connect the
 Implement the evaluation logic by interconnecting the inputs of an F_2OUT3
block with the outputs of the following AND operations:
– The negated output QBAD (F_NOT) of the first channel driver with the
negated value of the first limit module output (QHN or QLN).
– The negated output QBAD (F_NOT) of the second channel driver with the
negated value of the second limit module output (QHN or QLN).
– The negated output QBAD (F_NOT) of the third channel driver with the
negated value of the third limit module output (QHN or QLN).

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9 Hardware configuration and wiring of three sensors (2oo3) with redundant F-AI (2oo2) and
9 Hardware configuration and wiring of three

sensors (2oo3) with redundant F-AI (2oo2)
and evaluation in the user program
There are additional 2oo3 evaluation architectures in which the three sensors are
wired to redundant F-AIs.
As with previous architectures, this 2oo3 evaluation scheme refers to applications
that require two sensors to achieve the required security level. In this architecture,
the third sensor increases the availability. Two of three sensors have to function.
If at least two sensors indicate a trigger condition, the safety logic is triggered.
Note These architectures are able to achieve the safety integrity level SIL3 because
the three signals are evaluated in the user program. However, to be SIL-
compliant, the entire safety function – including the field devices – must be
assessed according to IEC 61508/IEC 61511.
Figure 9-1 illustrates a block diagram with redundant F-AI. This optional 2oo3
architecture uses three sensors and two redundant F-AIs in two ET 200M racks.
The three sensors in the diagram are wired to channels 0, 1 and 2 of both F-AIs.

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Figure 9-1: 2oo3 optional architecture with redundant modules
F-AI
Ch 0.. 5
Sensor 1
0
Sensor 2
1
Sensor 3 CPU
2
F _ CH _AI
2 oo 3
Voting
Logic
F-AI
Ch 0.. 5
0
This redundant 2oo3 architecture is one possible variant.

Although it uses an F-AI less than the previously described architecture, it has
similar availability. If only a few fail-safe analog inputs are needed, this variant is a
more cost-effective alternative.
The non-redundant version is also a possible option when only one F-AI is
available. It allows for high sensor availability, but compromises the higher
availability of the F-AI.

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Failed component detected? Tripping of the
safety function
Sensor 1 Sensor 2 Sensor 3 F-AI 1 F-AI 2 possible?
X No No X No Yes (not required)
No X No
No No X
X No No No X
No X No
No No X
X X X Yes Yes Yes
X Yes Yes X X
Yes X Yes
Yes Yes X
9.1 PFD calculation


formula:
PFD2oo3 = PFDSensor + 2 PFDF-AI + PFDCPU

9
9

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9.2 Wiring
A simplified example of the 2oo3 evaluation scheme with redundant F-AI and
evaluation in the user program is illustrated in Fig. 9-2. The first sensor is wired to
channel 0 (terminals 3, 4, 5) of both F-AIs, the second sensor is wired to channel 1
(terminals 6, 7, 8) and the third sensor to channel 2 (terminals 9, 10, 11) of both
F-AIs. Please note that this architecture also requires two Zener diodes for each
sensor. The first Zener diode has an avalanche voltage of 6.2 V and the second
one has an avalanche voltage of 5.6 V. Another two diodes are also used for
decoupling the voltage supply. The diodes and Zener diodes are needed in case
one of the F-AIs is out of service (e.g. module failure).
Fig. 9-2: 2oo3 evaluation in the user program, redundant F-AI, 3-channel transmitter, 2-wire,
internal supply
2-Wire
Current
Transmitter
2-Wire
Current
Transmitter
2-Wire
Current
Transmitter
Process variable is acquired with


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For the 2oo3 evaluation scheme with redundant F-AI and evaluation in the user
program, the F-AIs are configured in the STEP 7 HW Config.
Fig. 9-3 illustrates the example of a hardware configuration.
In this example, there is an ET 200M (IM153-2) with PROFIBUS address 3 and a
second ET 200M with PROFIBUS address 4. Each ET 200M contains one F-AI in slot 4.
For further information on hardware configuration, see \4\ in the "Links and
Literature" chapter.
Fig. 9-3: 2oo3 evaluation scheme with redundant F-AI and evaluation in the user program -
hardware configuration plan
F-AIs.
settings are made with PROFIBUS address 3 using the F-AI in the ET 200M. The
settings are summarized in Table 9-2.

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Fig. 9-4: 2oo3 evaluation scheme with redundant F-AI and evaluation in the user program -
Table 9-2: 2oo3 evaluation scheme with redundant F-AI and evaluation in the user program
Parameter Description / Recommendations Desired setting or
permissible value
range
Redundancy Shows whether the F-AI is acting as part of a Two (2)
redundant pair or not. modules
Remark:
to 2 modules.
Redundant Used for selecting the redundant partner
module module.
redundant module.
You can find a description of the hardware parameters at the end of section 0.

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Although this evaluation scheme uses redundant F-AIs, only three F_CH_AI
F-channel drivers are needed in the logic. The F-channel drivers can be added and
configured automatically from the SIMATIC Safety Matrix or manually using the
STEP 7 CFC Editor. In both cases, the F-channel drivers must be connected to the
analog sensor signal of the F-AI with the lowest I/O address.
The logic is compiled when the F-channel drivers are configured and the evaluation
logic is complete.
If the option to generate module drivers is activated during compilation, the
corresponding F_PS_12 module drivers are automatically added to the logic and
configured during the compilation. The F-channel driver selects the valid signal
After the three sensor signals have been added to the hardware configuration, the
2oo3 evaluation logic can be implemented in the user program. One option is to
use the SIMATIC Safety Matrix Engineering Tool (for further relevant information,
see \5\ in the "Links and Literature" chapter).
The actual evaluation logic for the 2oo3 evaluation scheme with redundant F-AI
and evaluation in the user program is the same as that described in the Section
8.4.1 (Configuring with Safety Matrix).
evaluation logic for the CPU by means of the STEP 7 CFC Editor. There are two
ways to implement the CFC logic:
The logic for both options corresponds to the solutions described in Chapter 8.4.2.

"Trip on bad quality" is not enabled. The input signals are not monitored for a
maximum delta.
Figure 9-5 shows an example logic for 2oo3 evaluation in the CFC Editor, which
does not take channel faults into account. Please note that this example starts from
a MAX limit and that the output of the evaluation logic is switched off to reach the
safe state

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Figure 9-5: CFC Logic – Without channel fault evaluation

below the limit.
signals.

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The example logic in Figure 9-5 works as follows:

 If at least two of the three analog sensors report a normal value
 If at least two analog sensors report an upper limit violation

 Create an F_CH_AI F-channel driver for the first analog sensor and connect
the corresponding I/O signal to the block. Use a limit block
 Create an F_CH_AI F-channel driver for the third analog sensor and connect
the corresponding I/O signal to the block. Use a limit block
 Connect the negated outputs of the limit value blocks (QHN or QLN) with the
inputs of an F_2OUT3 block in order to generate the signal for the trigger command.

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"Trip on bad quality" is enabled. The input signals are not monitored for a
maximum delta.
Fig. 9-6 shows an example logic for 2oo3 evaluation in the CFC Editor, which takes
channel faults into account. Please note that this example starts from a MAX limit
and that the output of the evaluation logic is switched off to reach the safe state

signals.

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 If at least two of the three analog sensors report a normal value without
channel faults (here: a process value lower than 90), the output of the
 If two or more analog sensors report an upper limit violation without channel
fault (here: a process value greater than or equal to 90), the output of the
 If two or more analog sensors report a channel fault, the output of the
 If one sensor reports a channel fault and two sensors do not report a channel
fault, only the values of the sensors without channel faults are used for the
evaluation logic.

 Create an F_CH_AI F-channel driver for the first analog sensor and connect the
 Create an F_CH_AI F-channel driver for the third analog sensor and connect the
 Implement the evaluation logic by interconnecting the inputs of an F_2OUT3
block with the outputs of the following AND operations:
– The negated output QBAD (F_NOT) of the first channel driver with the
negated value of the first limit module output (QHN or QLN).
– The negated output QBAD (F_NOT) of the second channel driver with the
negated value of the second limit module output (QHN or QLN).
– The negated output QBAD (F_NOT) of the third channel driver with the
negated value of the third limit module output (QHN or QLN).

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10 Calculating the PFD value
APPENDIX

The PFD value for the F-AI can be found in the "S7-300 Programmable Controller,
Fail-Safe Signal Modules" manual (see \6\ in the "Links and Literature" chapter). In
the technical data of the SM 336; F-AI 6 x 0/4 ... 20 mA HART or as a download on
the Internet (see \11\ in the in the "Links and Literature" chapter).
The PFD values apply for the specified service lives. It is not necessary and
impossible to proof test the hardware within this time. A replacement must take
place at the end of the service life.
Table 10-1: PFD value for the F-AI

Fail-safe performance features
After a service life of 20 years 1-channel 2-channel
Low demand mode < 1.00E-04 < 1.00E-05
(average probability of failure on demand) SIL 3
You can find the PFD value for the F-CPU in the manual "Safety Engineering in
SIMATIC S7" (see \8\ in the "Links and Literature" chapter) or as a download on
the Internet (see \11\ in the "Links and Literature" chapter).
Table 10-2: PFD value for F-CPUs

CPU Order number Low demand mode (average
probability of failure on demand)
Proof test interval 10 years 20 years
< 1.9 E-04 < 3.8 E-04
CPU 410-5H 6ES7 410-5HX08-0AB0
< 2.8 E-04* < 5.6 E-04*
< 1.9 E-04 < 3.8 E-04
CPU 410E 6ES7 410-5HM08-0AB0
< 2.8 E-04* < 5.6 E-04*
< 1.9 E-04 < 3.8 E-04
CPU 410SIS 6ES7 410-5FM08-0AB0
< 2.8 E-04* < 5.6 E-04*
CPU 412-5H PN/DP 6ES7 412-5HK06-0AB0 < 1.9 E-04 < 3.8 E-04
CPU 414-5H PN/DP 6ES7 414-5HM06-0AB0 < 1.9 E-04 < 3.8 E-04
CPU 416-5H PN/DP 6ES7 416-5HS06-0AB0 < 1.9 E-04 < 3.8 E-04
CPU 417-5H PN/DP 6ES7 417-5HT06-0AB0 < 1.9 E-04 < 3.8 E-04
* When used in the extended temperature range up to max. 70 °C.

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When calculating the PFDavg for a safety function, an additional PFD value must
be added for the safety-related communication.
Table 10-3
Safety-related Low demand mode After a service life of
communication (average probability of
failure on demand)
< 1E-05* 20 years
*Note for S7-300/400 F-CPUs:
The PFDavg value is valid under the assumption that a maximum of 25 fail-safe
I/Os are involved in a safety function. If more than 25 fail-safe I/Os are used, you
must also add 3.5E-7 fail-safe I/O for this safety function.

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11 Recommendations for power supply and grounding measures
11 Recommendations for power supply and

grounding measures
This section provides guidelines on basic power supply and grounding measures
for SIMATIC S7-400 F/FH systems. For further relevant information, please see \9\,
\6\ and \7\ in the "Links and Literature" chapter.
11.1 Power supply

11.1.1 Infeed
The power feed should be routed to a power feed unit installed as part of the
cabinet system. Please note that each power feed should have an independent
power feed unit. The power feed unit should have a number of terminals with
overcurrent protection. To increase system availability, a circuit breaker should be
used for overcurrent protection. A second power feed (which requires a second
power feed unit in the cabinet) can be used for improved system availability.
The power feed unit should have a connection for each conductor of the infeed:
 Cable
 Neutral / return conductor and
 GND
The ground connection for the infeed should be marked or color coded so that it
can be recognized as a ground connection. This ground connection must be
connected to the housing with low resistance. The ground connection terminal
should be held in place mechanically to ensure ground protection.
The infeed should have individual distribution terminals for connecting the loads in
the cabinet. The distribution terminals should be grouped, each with a ground
terminal for ground connections. Additional ground connections are required to
ground the rack used for mounting the system components.
11.1.2 System power supply
The system power supply outputs cabinet-specific 24 V DC for the cabinet loads.
The system power supply should have multiple outputs with terminals for each line.
The system supply should be isolated from all other ground references – as well as
any load supplied with system power.
System power can be supplied via a discrete power supply connected to the infeed
(described in Section 11.1.1). The power supply is usually integrated per rack.
The power supply supplies the controllers and I/O modules with 24 V DC. The
power supply for the communication modules, as well as the communication itself
pass over the backplane bus modules. When using isolated modules, the
backplane current and communication from the field I/O are galvanically
isolated. This isolation has two benefits:
 Isolation of control level and field level
 Protection of the control level from noise and overvoltages
Larger systems can use the system power supply for the field level and a dedicated
rack power supply for the control level. This is advantageous if the field devices
require more power than what is provided by the SIMATIC standard power
supplies. In such cases, the design should support redundant power supplies.
Redundant power supply architectures increase system reliability in online repairs

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as long as common components (such as a common line protection circuit breaker)

are avoided.
System availability can also be increased by means of other technologies, such as
uninterruptible power supplies or DC backup systems. The use of such
technologies requires knowledge of the system (e.g. power supply buffering times,
reaction of controls and I/O devices to power interruption, etc.).
11.2 Grounding
11.2.1 Objective
There are three basic goals for grounding a system:

 Operator protection
 Protection against lightning or other sources of voltage peaks
 Elimination of electrical interference
The prevention of unwanted effects due to electrical interference is based on the
linear ground path method. The flow of non-static electrical energy requires a loop in
which the sum of the currents to a participant equals zero. To prevent the flow of
currents (i.e., electro-magnetic noise), the system design should not include loops.
The concept of a linear grounding (or common reference point) involves a direct
connection that prevents the formation of any loops. From any point in a system with
ground connection, there should be only one path leading from that point to the
grounding point.
The linear grounding method is limited when using distributed process control systems.
A distributed system is a system in which components are distributed locally in a plant.
In this type of architecture, the linear grounding method can be efficiently applied to
system components called units (functions) (or isolation islands). A unit can be defined
as follows:
 Galvanic isolation of other units
 Physical separation of other units (functions), so that electrical disturbances
are diverted locally
In systems with units, each part uses a local, linear ground bar to reduce lightning
and electronic noise.
11.2.2 Implementation
The grounding recommendations given in this section are specific to cabinets with
power supplies that supply system components with 24 V DC. The grounding rules
are simplified by placing the system supply in the individual cabinets. If the energy
is shared between the cabinets, the equipment should be in the immediate vicinity
to keep a single grounding reference point and maintain connections. A system
with a centralized power supply should be located within a lightning protection zone
(usually within a building or construction). For all systems outside a common
lightning protection zone, isolation techniques should be used to reduce the
susceptibility to interference. Typical isolation barriers include local power supplies,
optical communication for data highways, and potential-isolated signal transmission
techniques (e.g. relay contacts, etc.).

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Grounding
The cabinet design should keep the energy supply separate from other access
openings. The electric current should be connected to a single distribution unit
within the cabinet. As part of the power feed unit, there should be a connection
point for the cabinet grounding. This connection should include the necessary
conductors for the proper operation of the protection device and for operator
protection. The GND connection of the cabinet should be marked or color-coded. If
multiple current sources are used (e.g. for redundancy), you have to use
independent power feed units, and each current source should have its own
cabinet ground connection.
Shield terminations
Field wiring shield terminations should be standard for I/O modules. The physical
terminations for shielding should be provided at the termination location of the field
signal wires, referred to as a shield collection. The shield collection should be
isolated from mounting plates or rail assemblies within cabinets. Shield collections
must accommodate a ground connection. The ground connection connects a
shield collection to the local equal potential ground bar (LEPG).
To complete the shield installation, the LEPG bar must be connected to a ground
reference. The ground is preferably connected to a grounding system, which is also
used for grounding the neutral conductors of the power supply system. Most
industrial plants support a centralized grounding point for connecting "locally"
diverted grounding systems. The connection to ground reference should be as
follows:
 Low impedance (0.5 ohms or less)
 As short a physical path as possible
 Separate and independent from the safety ground connections required for
operator protection
Please note that the grounding of shields at one location provides protection from
low frequency noise encountered in industrial environments. Care should be taken
to ensure no other connections to ground occur for shields.
DC grounding
Power supplies are typically installed in the cabinets to supply the operating
voltage of 24 V DC. The power supplies have no connection to ground or power
feeds. Depending on the user requirements, the system works in either an
ungrounded mode (floating) or connected to a user-specified reference point.

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System setup
S7-400 F/FH systems (including controllers and I/O modules) can work in
grounded or ungrounded mode. To accommodate both operating modes, the
system design includes a jumper that creates a reference potential to ground
connection.
When the jumper is removed, the reference potential is disconnected
from the housing ground.
Depending on the product, the bridge is either part of the hardware module
(see Figure 11-1) or of the system backplane (see Figure 11-2).
Figure 11-1: Installation location of the bridge with IM-153 (ET 200M interface module)
Lage
Jumper der Brücke
location on S7- Entfernen Sie die to
Remove jumper Brücke
eliminate
beiIM-153
300 and IM-153 Modulen
modules für erdfreien Aufbau
frame connection
Figure 11-2: Location of grounding for S7-400 modules

Ungrounded configuration Grounded configuration
Rack
Galvanic connection
Reference point
Connection Connection
Spring lock washer Spring lock washer
Original screw M4x8 Original screw M4x8
Anschluss
Connection to rackder
for
DC groundingder
Masse S7-400
Lastspannung
modules

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12 MTA (Marshalled Termination Assembly)

The MTA terminal modules (Marshalled Termination Assemblies) offer the
possibility of connecting field devices, sensors and actuators in a simple, quick and
safe manner to the signal modules of the ET 200M. They can be used to
significantly reduce the required work for cabling and commissioning, and prevent
wiring errors. The individual MTA terminal modules are each tailored to specific I/O
modules from the ET 200M range.
The F-AI HART module described in this documentation can be combined with the
"6 Channel F-Analog Input HART MTA" (6ES7650-1AH62-5XX0). This MTA can be
used for redundant and safety-oriented applications.
Properties
MTAs are characterized by the following properties:
 Redundant 24 V DC power supply with LED display
 Screw-type terminals for direct (1:1) connection of field devices, sensors and actuators
 Fuse with LED indicator for each I/O channel
 Pre-assembled cables to connect the MTA with the I/O module
 With 50/25-pole D-sub connector on the MTA side
 and 40/20-pole Siemens front panel connector for ET 200M module

 On-board simulation capabilities (wire break, to switch ON/OFF a channel)
 Tested as a PCS 7 system component and approved with appropriate
approvals (FM, UL, CE, ATEX, TÜV (German Technical Inspectorate)).
Fig. 12-1: F-AI MTA - Layout

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The F-AI MTA and the F-AI module are connected to each other over a
pre-assembled connecting cable. The custom length cable is shown below in
Fig. 12-2.
Fig. 12-2: F-AI MTA - connecting cable
Fig. 12-3 illustrates an example of how to wire a 4-wire transmitter (self-powered)

to the F-AI MTA.
Fig. 12-3: four-wire transmitter (self-powered)

Fig. 12-4 illustrates an example of how to wire a 4-wire transmitter (with external
power supply) to the F-AI MTA.
Fig. 12-4: Four-wire transmitter (with external power supply)

Entry ID: 24690377, V3.3, 12/2017 130
Fig. 12-5 illustrates an example of how to wire a 2-wire transmitter to the F-AI MTA.
Fig. 12-5: two-wire transmitter
An additional connecting cable is connected to the additional module connection

on the MTA for voting architectures that contain a redundant module.
You can find further information under \3\ in the "Links and Literature" chapter.

Entry ID: 24690377, V3.3, 12/2017 131
13 Glossary
13 Glossary
The following table shows the abbreviations used in the document.
Table 13-1 Glossary
Abbreviation Meaning
MooN M-out-of-N channel system
MooND M-out-of-N channel system, extended diagnostics
1oo1 Architecture type: 1 channel system, loss of safety if a channel is faulty.
(1-out-of-1)
1oo1D Architecture type: 1 channel system, loss of safety if a channel is faulty;
extended diagnostics
1oo2 Architecture type: 2 channel system, safety maintained if a channel is
faulty.
1oo2D Architecture type: 2 channel system, safety maintained if a channel is
faulty; extended diagnostics.
β CCF factor - The relationship between the probability of occurrence of a
CCF and the probability of any fault. β is dependent on the system
components, typical values for β are in the range of 1 % and 5 %.
CCF Common Cause Failure – These are errors that affect two or more
separate channels or components in a system. A CCF causes the
system to fail
CPU Central processing unit

IEC61508 Basic standard and basis for safety standardization
IEC61511 Based on the IEC61508, sector-specific standard for the process
industry
MTA Marshalled Termination Assemblies
PFD Probability of Failure on Demand,
Failure probability upon usage request of the safety function
(requested less than once a year)
Probability of a safety function failure upon request
SIL Safety Integrity Level:
safety level; level of risk reduction
SIS Safety Instrumented System

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14 Links andLiterature
14 Links andLiterature
Table 14-1
Topic
\1\ Siemens Industry Online Support
http://support.industry.siemens.com
\2\ Link to this entry
https://support.industry.siemens.com/cs/ww/en/view/24690377
\3\ ET 200M Marshalled Termination Assemblies Remote I/O Modules
\4\ SIMATIC Configuring Hardware and Communication Connections STEP 7 V5.5
\5\ SIMATIC Industrial Software Safety Matrix
\6\ SIMATIC Automation System S7-300 ET 200M Distributed I/O Device Fail-safe
signal modules
\7\ Automation System S7-400 Hardware and Installation
\8\ SIMATIC Industrial Software Safety Engineering in SIMATIC S7
\9\ SIMATIC PCS 7 Engineering System (V9.0)

\10\ SIMATIC S7 F Systems: Execution times of fail-safe blocks, runtime of the F
shutdown group, monitoring and response times
\11\ Which values can you use with F CPUs and products of the ET 200 family for PFD
and PFHD?
\12\ SIMATIC Industrial software S7 F/FH Systems - Configuring and Programming
15 Change documentation
Table 15-1
Version Date Modifications
V1.0 04/2007 First version
V2.0 12/2007 New hardware and software considered, supplemented by
MTA
V2.1 05/2009 Update
V3.0 08/2015 Complete revision
V3.1 08/2017 Update
V3.2 09/2017 Update
V3.3 12/2017 Improved wording and expansion

Entry ID: 24690377, V3.3, 12/2017 133

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Wiring and Voting

Architectures for failsafe

Warranty and liability

Wiring and Voting Architectures for failsafe F-AI

3.2 Wiring ................................................................................................. 27

Wiring and Voting Architectures for failsafe F-AI

5.4.2 Configuring with CFCs ....................................................................... 62

7.2.2 Wiring using an MTA (Marshalled Termination Assembly) ................ 86

Wiring and Voting Architectures for failsafe F-AI

APPENDIX ................................................................................................................. 123

Wiring and Voting Architectures for failsafe F-AI

Fig. 1-1: Example 1 - overview

Signals PT- 400B Failsafe Discrete

Wiring and Voting Architectures for failsafe F-AI

Fig. 1-2: Example 1 – system configuration

Wiring and Voting Architectures for failsafe F-AI

1.2 Presented architectures

Wiring and Voting Architectures for failsafe F-AI

1.3 Properties for the fail-safe analog input module

 Firmware update using HW Config

Connection diagrams of the F-AI

Wiring and Voting Architectures for failsafe F-AI

Fig. 1-3: SM 336 address assignment; F-AI 6 x 0/4...mA HART

Fig. 1-4: SM 336 front view; F-AI 6 x 0/4...mA HART

Wiring and Voting Architectures for failsafe F-AI

Fig. 1-6: SM336 channel numbers; F-AI 6 x 0/4...20mA HART

Wiring and Voting Architectures for failsafe F-AI

2 Hardware configuration and wiring of one

Fig. 2-1: F-AI – 1oo1 architecture

With a hardware configuration according to Fig. 2-1, it is possible to achieve a

Table 2-1: Failure combinations

No No Yes (not required)

Wiring and Voting Architectures for failsafe F-AI

2.1 PFD calculation

PFD calculation formula

PFDIn = PFDSensor + PFDF-AI + PFDCPU

The PFDF-AI and PFDCPU values are located in Section 10.

Internal power supply

illustrates a wiring example for a 2-wire transmitter.

Wiring and Voting Architectures for failsafe F-AI

Wiring example for a 2-wire transmitter

Figure 2-2: Wiring for a 2-wire transmitter (internal sensor supply)

Wiring example for a 4-wire transmitter

Fig. 2-3: Wiring of a 4-wire transmitter (internal sensor supply)

Wiring and Voting Architectures for failsafe F-AI

External power supply (2-wire transmitter)

Fig. 2-4: Wiring of a 2-wire transmitter (external sensor supply)

Wiring and Voting Architectures for failsafe F-AI

External power supply (4-wire transmitter)

Fig. 2-5: Wiring of a 4-wire transmitter (external sensor supply)

Wiring and Voting Architectures for failsafe F-AI

2.2.2 Wiring using an MTA (Marshalled Termination Assembly)

Siemens provides MTAs (Marshalled Termination Assemblies). By using an F-AI

Fig. 2-6: MTA

Wiring and Voting Architectures for failsafe F-AI

2.3 Parameters for hardware configuration

Fig. 2-7: Symbol processing

Wiring and Voting Architectures for failsafe F-AI

Fig. 2-8: Hardware parameters