Controller for control of

industrial evaporator
EKC 315A

REFRIGERATION AND
AIR CONDITIONING Manual
Introduction

Application
The controller and valve can be used where there are require-
ments to accurate control of superheat and temperature in con-
nection with refrigeration.
E.g.:
• Cold store (air coolers)
• Processing plant (water chillers)
• A/C plant

Advantages
• The evaporator is charged optimally – even when there are great
variations of load and suction pressure
• Energy savings – the adaptive regulation of the refrigerant injec-
tion ensures optimum utilisation of the evaporator and hence a
high suction pressure
• Exact temperature control – the combination of adaptive
evaporator and temperature control ensures great temperature
accuracy for the media
• The superheating is regulated to the lowest possible value at
the same time as the media temperature is controlled by the
thermostat function

Functions
• Regulation of superheat
• Temperature control
• MOP function
• ON/OFF input for start/stop of regulation
• Input signal that can displace the superheat reference or the
temperature reference
• Alarm if the set alarm limits are exceeded
• Relay output for solenoid valve
• PID regulation
• Output signal following the temperature showing in the display

System
The superheat in the evaporator is controlled by one pressure
transmitter P and one temperature sensor S2.
The valve can be one of the following types:
• TQ (PHTQ, TEAQ)
• AKV (AKVA)
TQ is a modulating valve, and when this is used a solenoid valve
must also be used in the liquid line.
AKV is a pulsating valve.
Where the AKV valve is used it also functions as solenoid valve.
Temperature control is performed based on a signal from tem-
perature sensor S3 which is placed in the air current before the
evaporator. Temperature control is in the shape of an ON/OFF
thermostat that shuts off the liquid flow in the liquid line, either
via the solenoid valve in TQ applications or directly when AKV is
used.

2 Manual RS8CS302 © Danfoss 07-2005 EKC 315A

Operation

Superheat function
You may choose between two kinds of superheat, either:
• Adaptive superheat or
• Load-defined superheat

MOP
The MOP function limits the valve’s opening degree as long as the
evaporating pressure is higher than the set MOP value.

Override function
Via the analog input a displacement can be made of the tempera-
ture reference or of the superheat reference. The signal can either
be a 0-20 mA signal or a 4-20 mA signal. The reference can be
dsplaced in positive or negative direction.

External start/stop of regulation

The controller can be started and stopped externally via a contact
function connected to input terminals 1 and 2. Regulation is
stopped when the connection is interrupted. The function must
be used when the compressor is stopped. The controller then
closes the solenoid valve so that the evaporator is not charged
with refrigerant.

Relays
The relay for the solenoid valve will operate when refrigeration
is required. The relay for the alarm function works in such a way
thatr the contact is cut in in alarm situations and when the con-
troller is de-energised.

Modulating/pulsating expansion valve

In 1:1 systems (one evaporator, one compressor and one condens-
er) with small refrigerant charge TQ is recommended.

In a system with an AKV valve the capacity can be distributed by

up to three valves if slave modules are mounted. The controller
will displace the opening time of the AKV valves, so that they will
not pulsate at the same time.
Used as slave module is a controller of the type EKC 347.

Analog output
The controller is provided with an analog current output which
can be set to either 0-20 mA or 4-20 mA. The signal will either fol-
low the superheat, opening degree of the valve or the air tem-
perature.

PC operation
The controller can be provided with data communication so that it
can be connected to other products in the range of ADAP-KOOL®
refrigeration controls. In this way operation, monitoring and data
collection can be performed from one PC – either on the spot or in
a service company.
See also page 14.

EKC 315A Manual RS8CS302 © Danfoss 07-2005 3

Survey of functions
Function Para- Parameter by operation via
meter data communication
Normal display
Normally the superheat is shown (but the valve’s opening degree or air temperature SH / OD% / S3 temp
may also be selected. See o17).
Reference
Se point - TempSetpoint.
Regulation is performed based on the set value provided that there is no external
contribution (o10).
(Push both buttons simultaneously to set the setpoint).
Differential r01 Differential
When the temperature is higher than the reference plus the set differential, the sole-
noid valve’s relay will be activated. It will become deactivated when the temperature
drops below the set reference.

Ref. Diff.
Unit r05 Units
Here you select whether the controller is to indicate the temperature values in °C or 0: °C + bar
in °F. If indication in °F is selected, other temperature settings will also change over to 1: °F + psig
Fahrenheit, either as absolute values or as delta values (in AKM only °C + bar – is displayed
The combination of temperature unit and pressure unit is depicted to the right. – whatever the setting).
External contribution to the reference r06 ExtRefOffset
This setting determines how large a contribution is to be added to the set setpoint
when the input signal is max. (20 mA). See o10.
Correction of signal from S2 r09 Adjust S2
(Compensation possibility through long sensor cable).
Correction of signal from S3 r10 Adjust S3
(Compensation possibility through long sensor cable).
Start/stop of refrigeration r12 Main Switch
With this setting refrigeration can be started and stopped. Start/stop of refrigeration
can also be accomplished with the external switch function. See also appendix 1.
Define thermostat function r14 Therm. Mode
0: No thermostat function. Only the superheat is regulated
1: Thermostat function as well as regulation of superheat.
Alarm
The controller can give alarm in different situations. When there is an alarm all the
light-emitting diodes (LED) will flash on the controller front panel, and the alarm relay
will cut in.
Alarm for upper deviation A01 Hgh.TempAlrm
The alarm for too high S3 temperature is set here. The value is set in Kelvin. The alarm
becomes active when the S3 temperature exceeds the actual reference plus A01. (The
actual reference can be seen in u28).
Alarm for lower deviation A02 Low.TempAlrm
The alarm for too low S3 temperature is set here. The value is set in Kelvin. The alarm
becomes active when the S3 temperature drops below the actual reference minus
A02.
Alarm delay A03 TempAlrmDel
If one of the two limit values is exceeded, a timer function will commence. The alarm
will not become active until the set time delay has been passed. The time delay is set
in minutes.
With data communication the impor-
tance of the individual alarms can be
defined. Setting is carried out in the
“Alarm destinations” menu. See also
page 14

4 Manual RS8CS302 © Danfoss 07-2005 EKC 315A

Control parameters

P: Amplification factor Kp n04 Kp factor

If the Kp value is reduced the regulation becomes slower.
I: Integration time Tn n05 Tn sec.
If the Tn value is increased the regulation becomes slowe
D: Differentiation time Td n06 Td sec.
The D-setting can be cancelled by setting the value to min. (0).)
Max. value for the superheat reference n09 Max SH
Min. value for the superheat reference n10 Min SH
Warning! Due to the risk of liquid flow the setting should not be lower than approx.
2-4 K.
MOP n11 MOP (Bar)
If no MOP function is required, select pos. Off. (A value of 60 bar corresponds to Off )
AKV valve's time period in seconds n13 AKV per. time
Should only be set to a lower value if it is a decentralised plant and the suction pres-
sure fluctuates a lot and in line with the opening of the AKV valve.
Stability factor for regulation of superheat n18 Stability
With a higher value the control function will allow a greater fluctuation of the super-
heat before the reference is changed. The value should only be changed by specially
trained staff.
Damping of amplification near reference value n19 Kp Min
This setting damps the normal amplification Kp, but only just around the reference
value. A setting of 0.5 will reduce the KP value by half.
The value should only be changed by specially trained staff.
Amplification factor for the superheat (AKV only and only in 1:1 plant) n20 Kp T0
This setting determines the valve’s opening degree as a function of the change in
evaporating pressure. An increase of the evaporating pressure will result in a reduced
opening degree. When there is a drop-out on the low-pressure thermostat during
start-up the value must be raised a bit. If there is pendling during start-up the value
must be reduced a little.
The value should only be changed by specially trained staff.
Definition of superheat regulation (Ref. appendix 6) n21 SH mode
1: Lowest permissible superheat (MSS). Adaptive regulation.
2: Load-defined superheat. The reference is established based on the line formed by
the three points: n09, n10 and n22.
Value of min. superheat reference for loads under 10% n22 SH Close
(The value must be smaller than ”n10”).
Standby temperature when valve closed (TQ only) n26 TQ Kmin
The TQ actuator is kept warm when the valve reaches its closing point. As the closing
point cannot be defined completely accurately due to tolerances and pressure varia-
tions, the setting can be changed, as required (how ”tightly”/securely the valve is to
close). See also appendices 1 and 5.
Standby temerature when valve open (TQ only) n27 TQ Kmax
The TQ actuator’s temperature is kept low when the valve reaches its fully open posi-
tion. Here you set how many degrees the temperature is to be above the expected
open temperature in completely open position. The greater the value, the surer it
is that the valve will be open, but it will also react more slowly when it has to close
again.
Max. opening degree (AKV only) n32 AKV/A OD Max
The valve’s opening degree can be limited. The value is set in %.

EKC 315A Manual RS8CS302 © Danfoss 07-2005 5

Miscellaneous
Address
If the controller is built into a network with data communication, it must have an Following installation of a data com-
address, and the master gateway of the data communication must then know this munication module, the controller can
address. be operated on a par with the other
These settings can only be madewhen a data communication modulehas been controllers in ADAP-KOOL® refrigera-
mounted in the controller and the installation of the data communication cable has tion controls.
been completed.
This installation is mentioned in a separate document “RC8AC”
The address is set between 0 and 119 o03 -
The address is sent to the gateway when the menu is set in pos. ON o04 -
(The setting will automatically change back to Off after a few seconds.)
Valve and output signal o09 AO type
Define here the valve that is to regulate and the current signal to be transmitted to
the analog output ”AO”. The current signal will show the superheat if o17=1. Or open-
ing degree of the valve, if O17=2. Or the S3 temperature if o17=3 0:Off
1: TQ valve and 0-20 mA
2: TQ valve and 4-20 mA
3: AKV valve and 0-20 mA
4: AKV valve and 4-20 mA
5: AKV valve and signal for an other controller. See appendix 3.
Input signal for reference displacement o10 AI A type
Definition of function and signal range.
0: No signal
1: Displacement of temperature reference with 0-20 mA
2: Displacement of temperature reference with 4-20 mA
3: Displacement of superheat reference with 0-20 mA
4: Displacement of superheat reference with 4-20 mA
(4 or 0 mA will not give a displacement. 20 mA will displace the reference by the value
set in menu r06)
Frequency o12 50 / 60 Hz
Set the net frequency. (50=0, 60=1)
Select signal for showing display o17 Display mode
Here you can select the signal to be shown in the normal display.
The signal is also transmitted to the analog output. See O09.
1: Superheat
2: Valve’s opening degree
3: Air temperature
(If you during operation give the lower button a brief push, you can see the follow-
ing: The S3 temperature, if 1 has been selected. The superheat reference, if 2 has been
selected. Temperature reference if 3 has been selected).
Manual control of outputs o18 -
For service purposes the individual relay outputs and the AKV/A output can be forced
into position ON. However only when regulation has been stopped.
OFF: No override
1: Relay to the solenoid valve is ON.
2: AKV/A output is ON.
3: Alarm relay is activated (connection established between terminals 29 and 31).

Working range for pressure transmitter o20 MinTrans Pres.

Depending on the application a pressure transmitter with a given working range
is used. This working range (say, -1 to 12 bar) must be set in the controller. The min.
value is set.
The max. value is set o21 Max TransPres.
(Setting for the function o09) o27 AO min. value
Set the temperature value or opening degree of the valve where the output signal
must be minimum
(0 or 4 mA)
(Setting for the function o09) o28 AO max. value
Set the temperature value or opening degree of the valve where the output signal
must be maximum (20 mA). (With a temperature range of 50 K (differential between
the settings in o27 and o28) the dissolution will be better than 0.1 K. With 100 K the
dissolution wil be better than 0.2 K.)

6 Manual RS8CS302 © Danfoss 07-2005 EKC 315A

Refrigerant setting o30 Refrigerant
Before refrigeration can be started, the refrigerant must be defined. You can select the
following refrigerants:
1=R12. 2=R22. 3=R134a. 4=R502. 5=R717. 6=R13. 7=R13b1. 8=R23. 9=R500.
10=R503. 11=R114. 12=R142b. 13=User defined. 14=R32. 15=R227. 16=R401A.
17=R507. 18=R402A. 19=R404A. 20=R407C. 21=R407A. 22=R407B. 23=R410A.
24=R170. 25=R290. 26=R600. 27=R600a. 28=R744. 29=R1270.
(Warning: Wrong selection of refrigerant may cause damage to the compressor).
Service
A number of controller values can be printed for use in a service situation
Read valve’s actuator temperature (TQ) u04 Actuator temp.
Read reference for valve’s actuator temperaturer (TQ) u05 Actuator Ref.
Read value of external current signal (AIA) u06 AI A mA
Read value of transmitted current signal u08 AO mA
Read status of input DI (start/stop input) u10 DI
Read the ongoing cutin time for the thermostat or the duration of the last completed u18 Ther. RunTime
cutin
Read the temperature at the S2 sensor u20 S2 temp.
Read superheat u21 SH
Read the control’s actual superheat reference u22 SH ref.
Read the valve’s opening degree u24 OD%
Read evaporating pressure u25 Evap. pres. Pe
Read evaporating temperature u26 Evap. temp Te
Read the temperature at the S3 sensor u27 S3 temp.
Read control reference u28 Temp. ref
(Set setpoint + any contribution from external signal)
Read value of current signal from pressure transmitter (AIB) u29 AI B mA
-- DO1 Alarm
Read status of alarm relay
-- DO2 Liq. Valv
Read status of relay for solenoid valve
Operating status
The controller’s operating status can be called forth by a brief (1s) activation of the EKC State
upper button. If a status code exists it will be shown. (Status codes have lower priority (0 = regulation)
than alarm codes. This means that status codes cannot be seen if there is an active
alarm code.
The individual status codes have the following meanings:
S10: Refrigeration stopped by the internal or external start/ stop. 10
S11: Thermostat is cutout 11

EKC 315A Manual RS8CS302 © Danfoss 07-2005 7

Operation Menu survey SW =1.2x
Para- Factory
Function Min. Max.
Display meter setting
The values will be shown with three digits, and with a setting you Normal display
can determine whether the temperature are to be shown in °C or Shows the actual superheat/ valve's opening
in °F. degree/ temperature - K
Define view in O17
If you wish to see the expansion valve’s actual
opening degree, give the lower button a brief - %
push (1s). Define view in O17
Reference
Set the requirede set point - -60°C 50°C 10
Light-emitting diodes (LED) on front panel Differential r01 0,1 K 10,0 K 2.0
There are LED’s on the front panel which will light up when the
Units (0=°C+bar /1=°F+psig) r05 0 1 0
belonging relay is activated.
External contribution to the reference r06 -50 K 50 K 0
The upper LED will indicate the valve’s opening degree. A short
pulse indicates a small liquid flow and a long pulse a heavy liquid Correction of signal from S2 r09 -10.0 K 10.0 K 0.0
flow. The other LED will indicate when the controller calls for Correction of signal from S3 r10 -10.0 K 10.0 K 0.0
refrigeration. Start / stop of refrigeration r12 OFF On 1
The three lowermost LED’s will flash, if there is an error in the regu- Define thermostat function
r14 0 1 0
lation. (0= no thermostat function, 1=On/off thermostat)
In this situation you can upload the error code on the display and Alarm
cancel the alarm by giving the uppermost button a brief push. Upper deviation (above the temperature setting) A01 3.0 K 20 K 5.0
Lower deviation (below the temperature setting) A02 1K 10 K 3.0
Alarm’s time delay A03 0 min. 90 min. 30

The buttons Regulating parameters

When you want to change a setting, the two buttons will give you P: Amplification factor Kp n04 0.5 20 3.0
a higher or lower value depending on the button you are push- I: Integration time T n05 30 s 600 s 120
ing. But before you change the value, you must have access to the D: Differentiation time Td (0 = off ) n06 0s 90 s 0
menu. You obtain this by pushing the upper button for a couple
Max. value of superheat reference n09 2K 50 K 6
of seconds - you will then enter the column with parameter codes.
Min. value of superheat reference n10 1K 12 K 4
Find the parameter code you want to change and push the two
buttons simultaneously. When you have changed the value, save MOP (max = off ) n11 0.0 bar 60 bar 60
the new value by once more pushing the two buttons simultane- Period time (only when AKV/A valve is used) n13 3s 10 s 6
ously. Stability factor for superheat control.
n18 0 10 5
Changes should only be made by trained staff
Gives access to the menu (or cutout an alarm) Damping of amplification around reference value
n19 0.2 1.0 0.3
Changes should only be made by trained staff
Gives access to changes Amplification factor for superheat
n20 0.0 10.0 0.4
Changes should only be made by trained staff
Saves a change Definition of superheat control
n21 1 2 1
1=MSS, 2=LOADAP
Value of min. superheat reference for loads under
n22 1 15 2
10%
Standby temperature when valve closed (TQ valve
Examples of operations only) n26 -15 K 20 K 0
Changes should only be made by trained staff
Standby temperature when valve open (TQ valve
Set set-point only) n27 -15 K 70 K 20
1. Push the two buttons simultaneously Changes should only be made by trained staff
2. Push one of the buttons and select the new value Max. opening degree
n32 0 100 100
3. Push both buttons again to conclude the setting Changes should only be made by trained staff
Miscellaneous

Set one of the other menus Controller’s address o03* 0 119 -

1. Push the upper button until a parameter is shown ON/OFF switch (service-pin message) o04* - - -
2. Push one of the buttons and find the parameter you want to Define valve and output signal:
change 0: Off
3. Push both buttons simultaneously until the parameter value is 1: TQ. AO: 0-20 mA
shown 2: TQ. AO: 4-20 mA o09 0 5 0
3: AKV, AO: 0-20 m
4. Push one of the buttons and select the new value
4: AKV, AO: 4-20 mA
5. Push both buttons again to conclude the setting 5: AKV, AO: EKC 347-SLAVE

8 Manual RS8CS302 © Danfoss 07-2005 EKC 315A

Define input signal on the analoge input AIA: The controller can give the following messages:
0: no signal,
E1 Fault in controller
1: Temperature setpoint. 0-20 mA
o10 0 4 0
2: Temperature setpoint. 4-20 mA E11 Valve’s actuator temperature outside its range
3: Displacement of superheat reference. 0-20 mA
4: Displacement of superheat reference. 4-20 mA E15 Cut-out S2 sensor
Set supply voltage frequency o12 50 Hz 60 Hz 0 E16 Shortcircuited S2 sensor
Select display for ”normal picture” E17 Error message Cut-out S3 sensor
1: Superheat E18 Shortcircuited S3 sensor
o17 1 3 1
2: Valve’s opening degree The input signal on terminals 18-19 is outside
E19
3: Air temperature the range.
Manual control of outputs:
The input signal on terminals 14-15 is outside
OFF: no manual control E20
the range (P0 signal)
1: Relay for solenoid valve: select ON o18 off 3 Off
A1 High-temperature alarm
2: AKV/A output: select ON
3: Alarm relay activated (cut out) A2 Alarm message Low-temperature alarm
Working range for pressure transmitter – min. A11 No refrigerant has been selected
o20 -1 bar 60 bar -1.0
value
Working range for pressure transmitter – max.
o21 -1 bar 60 bar 12
value
(Setting for the function o09)
Set the temperature value or opening degree
o27 -70°C 160°C -35
where the output signal must be minimum (0 or
4 mA)
(Setting for the function o09)
Set the temperature value or opening degree
o28 -70°C 160°C 15
where the output signal must be maximum (20
mA)
Refrigerant setting
1=R12. 2=R22. 3=R134a. 4=R502. 5=R717.
6=R13. 7=R13b1. 8=R23. 9=R500. 10=R503.
11=R114. 12=R142b. 13=User defined. 14=R32.
o30 0 29 0
15=R227. 16=R401A. 17=R507. 18=R402A.
19=R404A. 20=R407C. 21=R407A. 22=R407B.
23=R410A. 24=R170. 25=R290. 26=R600.
27=R600a. 28=R744. 29=R1270.
Service
TQ valve's actuator temperature u04 °C
Reference of the valve's actuator temperature u05 °C
Analog input AIA (18-19) u06 mA
Analog output AO (2-5) u08 mA
Read status of input DI u10 on/off
Thermostat cut-in time u18 min.
Temperature at S2 sensor u20 °C
Superheat u21 K
Superheat reference u22 K
Read AKV valve’s opening degree u24 %
Read evaporating pressure u25 bar
Read evaporating temperature u26 °C
Temperature at S3 sensor u27 °C
Temperature reference u28 °C
Read signal at pressure transmitter input u29 mA
*) This setting will only be possible if a data communication module has been
installed in the controller.

Factory setting
If you need to return to the factory-set values, it can be done in this way:
- Cut out the supply voltage to the controller
- Keep both buttons depressed at the same time as you reconnect the supply voltage

EKC 315A Manual RS8CS302 © Danfoss 07-2005 9

Data
24 V a.c. +/-15% 50/60 Hz, 80 VA
Supply voltage (the supply voltage is galvanically separated from the
input and output signals)
Power consump- Controller 5 VA
tion TQ actuator 75 VA
AKV coil 55 VA
Current signal 4-20 mA or 0-20 mA
Input signal Pressure transmitter 4-20 mA from AKS 33
Digital input from external contact function
Sensor input 2 pcs. Pt 1000 ohm
Current signal 4-20 mA or 0-20 mA
Output signal
Load Max. 200 ohm
Relay output 1 pcs. SPST AC-1: 4 A (ohmic)
Alarm relay 1 pcs. SPST AC-15: 3 A (inductive)
Temperature signal from sen-
Input
Actuator sor in the TQ actuator
Output Pulsating 24 V a.c. to actuator
Data communica-
Possible to connect a data communication module
tion Ordering
Ambient During operation -10 - 55°C Type Function Code no.
temperature During transport -40 - 70°C
EKC 315A Superheat controller 084B7086
Enclosure IP 20
Data communication module
Weight 300 g EKA 173 084B7092
(accessories), (FTT 10 module)
Mounting DIN rail Data communication module
EKA 175 084B7093
Display LED, 3 digits (accessories), (RS 485 modul)
Terminals max. 2.5 mm multicore
2
Data communication module
EU Low Voltage Directive and EMC demands re CE- EKA 174 (accessories), (RS 485 module) 084B7124
marking complied with. with galvanic separation
Approvals
LVD-tested acc. to EN 60730-1 and EN 60730-2-9 Temperature sensor Pt 1000 ohm / Pressure transmitter type AKS 33 / TQ
EMC-tested acc. to EN50081-1 and EN 50082-2 Valves / AKV valves: ............. Kindly refer to catalogue RK0YG...

Connections
Necessary connections
Terminals: Data communication
25-26 Supply voltage 24 V a.c.
23-24 Supply to actuator
17-18 Only at TQ actuator: Signal from actuator
20-21 Pt 1000 sensor at evaporator outlet (S2)
14-15 Pressure transmitter type AKS 33
9-10 Relay switch for start/stop of solenoid valve
1-2 Switch function for start/stop of regulation. If a switch is
not connected, terminals 1 and 2 must be shortcircuited.

Application dependent connections

Terminal:
21-22 Pt 1000 sensor for measuring air temperature (S3)
12-13 Alarm relay
There is connection between 12 and 13 in alarm situations
and when the controller is dead
18-19 Current signal from other regulation (Ext.Ref.)
2-5 Current output for showing superheat or air temperature.
Or for signal to a slave module
3-4 Data communication
Mount only, if a data communication module has been
Wire length TQ:
mounted. See appendix 2
It is important that the installation of the data communi-
cation cable be done correctly. Cf. separate literature No.
RC8AC...

10 Manual RS8CS302 © Danfoss 07-2005 EKC 315A

Installation considerations
Accidental damage, poor installation, or site conditions, can give Danfoss wil not be responsible for any goods, or plant compo-
rise to malfunctions of the control system, and ultimately lead to a nents, damaged as a result of the above defects. It is the installer's
plant breakdown. responsibility to check the installation thoroughly, and to fit the
Every possible safeguard is incorporated into our products to necessary safety devices.
prevent this. However, a wrong installation, for example, could still Particular attention is drawn to the need for a “force closing” signal
present problems. Electronic controls are no substitute for normal, to controllers in the event of compressor stoppage, and to the
good engineering practice. requirement for suction line accumulators.

Your local Danfoss agent will be pleased to assist with further

advice, etc.

Appendix 1 Appendix 2

Interaction between internal and external start/stop functions Cable length for the TQ actuator
and active functions. The actuator must be supplied with 24 V a.c. ± 10%.
To avoid excessive voltage loss in the cable to the actuator, use a
Internal Start/stop Off Off On On thicker cable for large distances.
External Start/stop (DI) Off On Off On
Refrigeration (DO2) Off On
Wire cross section
Standby tempera-
TQ actuator Regulating
ture
Expansion valve relay Off On
Temperature monitoring No Yes
Sensor monitoring Yes Yes

Cable length

Appendix 3 Appendix 4

If the flow of refrigerant is to be distributed to several expansion If there are two evaporators sharing the same suction line, the
valves, this can be accomplished by using AKV valves and EKC signal from the pressure transmitter can be used by two control-
controllers as slave modules. lers.

Remember to open the functions in:

- EKC 315A's menu o09
- EKC 347's menu o09

EKC 315A Manual RS8CS302 © Danfoss 07-2005 11

Appendix 5 Appendix 6

Standby temperatures for TQ valves. The two types of regulation for superheat are, as follows:

TQ valve Adaptive superheat

The valve’s actuator temperature is limited, both when regula-
tion is stopped and when the valve is right out at the opening
point and closing point.
(The opening and closing points may fluctuate a couple of de-
grees up or down, depending on pressures and tolerances).

Regulation is here based on the evaporator’s load by means of

MSS search (MSS = lowest permissible superheat).
(The superheat reference is lowered to the exact point where
instability sets in).
The superheat is limited by the settings for min.and max.super-
heat.

Load-defined superheat

n26
The setting is based on the TQ valve’s closing curve. With a plus
value the valve can be kept slightly open. With a minus value the The reference follows a defined curve.This curve is defined by
valve can be closed completely. If the minus value is high you three values: the closing value, the min. value and the max.
can be sure that the valve will close, but then it will also react value. These three values must be selected in such a way that
slowly when it has to open again. the curve is situated between the MSS curve and the curve for
average temperature difference ∆Tm (temperature difference
n27 between media temperature and evaporating temperature.
This setting defines the number of degrees the actuator has to Setting example = 4, 6 and 10 K).
be warmer when the valve is completely open. If the value is
high you can be sure that the valve is completely open, but then
it will also react slowly when it has to close again.

12 Manual RS8CS302 © Danfoss 07-2005 EKC 315A

Start of controller
When the electric wires have been connected to the controller, 4. Follow the actual room temperature or superheat on the
the following points have to be attended to before the regulation display.
starts: (On terminals 2 and 5 a current signal can be transmitted
1. Switch off the external ON/OFF switch that starts and stops the which represents the display view. Connect a data collection
regulation. unit, if applicable, so that the temperature performance can be
2. Follow the menu survey on page 8, and set the various para- followed).
meters to the required values.
3. Switch on the external switch, and regulation will start.

If the superheating fluctuates

When the refrigerating system has been made to work steadily, Alternatively it may be due to the fact that the set regulation
the controller’s factory-set control parameters should in most parameters are not optimal.
cases provide a stable and relatively fast regulating system.
If the system however fluctuates this may be due to the fact that If the time of oscillation is longer than the integration time:
too low superheat parameters have been selected: (Tp > Tn , (Tn is, say, 240 seconds))
1. Increase Tn to 1.2 times Tp
If adaptive superheat has been selected: 2. Wait until the system is in balance again
Adjust: n09, n10 and n18. 3. If there is still oscillation, reduce Kp by, say, 20%
4. Wait until the system is in balance
If load-defined superheat has been selected: 5. If it continues to oscillate, repeat 3 and 4
Adjust: n09, n10 and n22.
If the time of oscillation is shorter than the integration time:
(Tp < Tn , (Tn is, say, 240 seconds))
1. Reduce Kp by, say, 20% of the scale reading
2. Wait until the system is in balance
3. If it continues to oscillate, repeat 1 and 2.

If the superheat has excessive underswing

during start-up
If you regulate with valve type AKV:
Adjust n22 a little bit up and/or n04 a little bit down.

If you regulate with valve type TQ:

Adjust n26 a littlle bit down

EKC 315A Manual RS8CS302 © Danfoss 07-2005 13

Data communication
This page contains a description of a few of the possibilities you If you want to know more about operation of controllers via PC,
will have when the controller is provided with data communi- you may order additional literature.
cation.

Example

Each controller is provided This cable is also connected to The gateway can now be con- At the service company a
with a plug-in module. a gateway type AKA 243/AKA nected to a modem. modem, gateway and PC with
245. system software type AKM
The controllers are then con- When an alarm occurs from have been installed.
nected to a two-core cable. This gateway will now control one of the controllers, the
the communication to and gateway will - via the modem All the controllers’ functions
Up to 119 controllers may be from the controllers. - make a phone call to the can now be operated from the
connected to one cable. service company. various menu displays.
It will collect temperature val-
ues and it will receive alarms. The programme will for exam-
When there is an alarm the ple upload all the collected
alarm relay will be activated for temperature values once a day.
two minutes.

Example of menu display Alarms

If the controller is extended 2 = Message
with data communication, it The alarm text is transmitted
will be possible to define the with status value 2. Later, when
importance of the transmitted the “message” lapses, the alarm
alarms. text is retransmitted, but now
The importance is defined with with status value 0.
the setting: 1, 2, 3 or 0. When
the alarm then arises at some 3 = Alarm
time, it will result in one of the As “1”, but the master gateway’s
following activities: relay output is not activated.

1 = Alarm 0 = Suppressed information

The alarm message is sent off The alarm text is stopped at
with alarm status 1. This means the controller. It is transmitted
that the gateway that is the nowhere.
master in the system will have
its alarm relay output activated
• Measurements are shown at • With a simple change-over for two minutes. Later, when
one side and settings at the the values can also be the alarm ceases, the alarm
other. shown in a trend diagram. text will be retransmitted, but
now with status value 0.
• You will also be able to see • If you wish to check earlier
the parameter names of the temperature measurements,
functions on page 4-6. you can see them in the log
collection.

14 Manual RS8CS302 © Danfoss 07-2005 EKC 315A

EKC 315A Manual RS8CS302 © Danfoss 07-2005 15
List of literature

Instructions RI8GT (extract from this manual).

Here you can see how controllers are mounted and programmed.

Installation guide for extended operation RC8AC

Here you can see how a data communication connection to ADAP-KOOL® Refrigeration control systems can be estab-
lished.

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products
already on order provided that such alternations can be made without subsequential changes being necessary in specifications already agreed.
RC-EM

All trademarks in this material are property of the respecitve companies. Danfoss and Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

16 Manual RS8CS302 © Danfoss 07-2005 EKC 315A