ETM II User Manual

(8COMP12LT03 V15)

This manual describes the Easy Tronic Micro II circuit board used to control the operation of an air screw compressor.

Description of board
The controller’s architecture is based on a microcontroller that governs machine processes through 5 output and 10 input terminals.
The outputs are controlled by electromechanical relays that control external contactors (in the electromechanical cabinet). The
terminal board is provided with one contact for each relay plus one common contact.
The controller is perfectly interchangeable with the existing one, and the connectors are mechanically and electrically compatible,
provided they are plugged in correctly (see Fig.3).

Board outputs:
- 1 for the motor relay
- 1 for the solenoid valve relay
- 1 for the cooling fan relay
- 1 for the star connection relay
- 1 for the delta connection relay

All the inputs operate under low voltage. The alarms and the remote control are on/off inputs that accept voltages up to 12 VAC.
The board requires an external three-phase isolation transformer (8TRACOMP10LT00, also present in COMP01) to control the
phase sequence.

Board inputs:
- 1 for the motor’s thermal circuit breaker alarm
- 1 for the rotation error alarm
- 1 for the temperature alarm
- 1 for the emergency button alarm
- 1 for the pressure switch
- 1 for remote control
- 1 for the pressure sensor
- 1 for the water sensor
- 1 for the temperature sensor
- 1 for the phase sequence

The circuitry is laid out on an aluminium panel with silk-screen printed polyester.
The panel also includes:
- 5 displays showing the working time and information from the sensors
- 5 LEDs for the alarm warnings
- 2 LEDs for compressor ON and power ON (these have been left to maintain compatibility with the previous board version)
- 3 keys: Start, Reset and Function (the Function key changes the parameters)

LT. Decription Date File name Prepared by Drawing Ref. Type of doc. Page Tot. pages

00 Manual 06/10/2012 Ghinelli Gianluca

A4 1 11
signature
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Electrical and mechanical details

Electrical details
Power supply: 12 VAC ±10%
Max. demand at 12 VAC: 200 mA
Working Temperature -15/+70°C
Relays: 5 (with NO contact connected to the common line)
Max. relay current: 230 VAC 8 A res. (the contacts ARE NOT suitable for large loads and can only be used for
controlling the relays and external power contactors)
Inputs voltage: 12 VAC ±10%
Supply voltage 4-20 mA: 8 VDC (Note: The board is designed to work with pressure sensors that accept a minimum
supply voltage of 8 V)

Mechanical details
Panel dimensions: 150x70 mm
Fastening holes: 4x Ø5 mm

Operation
Unless there are alarms or maintenance warnings, at start-up the display will show the pressure, the temperature, the total hours and
the motor hours. Briefly press FUNCTION (F) to go from one item to the next one.
Pressures and temperatures are displayed only if the relative sensors are enabled.

Start-up procedure:
Press START (I). If no alarm is displayed, the start-up cycle will be initiated:
a) Start-up standby: the standby LED will flash for a 20-second delay from the last time the motor was turned off.
b) Phase sequence check: the system verifies the presence of the phases in the first 30 seconds and their correct sequence for
10 seconds.
c) Compressor start-up: the screw LED flashes and energizes the line relay and the star relay; this stage lasts for a fixed
period of 5 sec.
d) Star-delta transition: the relay remains energized while the star relay is de-energized; this stage lasts for a fixed period of
5 msec.
e) Compressor running: the line relay remains energized and the delta relay is also energized; this stage lasts for 2 sec.
f) Compressor loading: the screw LED remains steadily on and the load solenoid valve relay is energized; this stage lasts
until the “no-load pressure set point” is reached.
g) No-load running: the screw LED flashes and the load solenoid valve relay is de-energized; this stage lasts for the time set
as “No-load time”.
If in the meantime the pressure drops below the value entered as “Load pressure set point”, the cycle restarts from point a),
otherwise the compressor goes on standby.
h) Standby: the standby LED remains on and the motor is off; when the pressure reaches the value entered as “Load pressure
set point” the cycle restarts from point a).

Shutdown procedure:
Press RESET (0) to start the shutdown procedure. The load solenoid valve is de-energized and the no-load cycle is started for a time
equal to the “Shutdown delay time” (the screw LED flashes), after which the controller switches off (screw LED and standby LED
off).

Remote control
When remote control is enabled, load and no-load operations are governed by the remote input. In this configuration the controller
will make sure that the remote input operates within the range of preset values (load and no-load set points).
If the no-load pressure is exceeded due to a malfunction in the remote control, the controller will assume control of compressor
operations and make it run according to the internal settings, and the display will show the message R_ALL.
If the malfunction is resolved, i.e., the remote control intervenes before the controller’s no-load settings, compressor functions are
resumed by the remote control and the message R_ALL disappears.
During normal remote operations the display shows the status of the input as R_OFF or R_ON; press FUNCTION (F) to scroll
through the compressor parameters (P, t, HT and HL). If the FUNCTION (F) key is not used for 10 seconds, the display goes back
to showing the status of the remote input.

Remote ON/OFF
Enabling the remote ON / OFF the compressor can be controlled from the entrance of remote. Remote control is active only if the
user gives consent by pressing the START (I) on the control unit (START LOCAL).
The display may have different indication, based on the state of the remote user consent (START LOCAL) and if it is enabled in the

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pressure sensor.
The display with remote ON / OFF enabled is as follows:

Pressure Sensor LOCAL Start REMOTE Input DISPLAY

OFF OFF Appears r_OFF
OFF ON Appears r_ON
Enabled ON OFF Appears r_OFF flashing (the controller is ready to go as
soon as the remote input is turned ON)
Appears r_ON for 5sec then the indication of pressure with
the prefix P (the control unit starts its cycle of operation, if
ON ON during the operation there is shown in the previous
configurations, the controller will start the shutdown process
and the display shows the corresponding status )
The indications are the same sensor enabled except the
Not enabled indication of the pressure that is replaced with the status of
the pressure switch with the prefix P (P_On, P_OFF);

Tab.1 Display with remote on / off enabled

NOTE: Any time an alarm occurs the compressor is immediately stopped.

Menus and parameters

The controller’s settings are based on 24 parameters that can be accessed and edited through 3 menus.
-User Menu (see Tab. 3)
-Service Menu (see Tab. 4)
-Factory Menu (see Tab. 5)

The Service Menu and the Factory Menu can be accessed only by pressing a combination of keys and entering a password.

Once you have accessed a menu, press START (increase) and RESET (decrease) to go the parameter you want to edit; every
parameter is identified by a letter and a number. After selecting a parameter, press FUNCTION to view its current value, then press
START or RESET to edit the value. Once you have changed the parameter, press FUNCTION to confirm the changes and return to
the parameter index.
If no key is pressed in the parameter index for 5 seconds, the menu is automatically exited.

The Service Menu and the Factory Menu can be accessed only by password.
Enter the password one digit at a time. After you press the key combination the display will show 4 zeroes, and the first one on the
left will be flashing. Press START to edit the flashing digit; press RESET to select the digit to be edited; press FUNCTION to
confirm the password: if the password is correct you can access the menu, otherwise you will be taken back to the main screen.

Parameters
−Oil temperature pre-alarm (delta): the delta of temperature (in °C) can be set as a function of the maximum alarm temperature.
For example, if the maximum temperature is set at 120 °C and the delta is 10 °C, the temperature pre-alarm will be given at 110 °C
by the flashing of the oil temperature alarm (this parameter is significant only if the temperature sensor is enabled).

−Maximum oil temperature: determines the maximum oil temperature (in °C) above which the system will report an alarm and
stop the compressor (this parameter is significant only if the temperature sensor is enabled).

−Minimum oil temperature: determines the minimum oil temperature (in °C) below which the system will report an alarm and
stop the compressor (this parameter is significant only if the temperature sensor is enabled).

−Fan starting temperature: determines the fan starting temperature; the threshold value has a fixed hysteresis of 10°C. For
example, if the fan starting temperature is set at 100°C, the fan will start at 100°C and stop at 90°C oil temperature (this parameter
is significant only if the temperature sensor is enabled).

−Thermal drift: determines the maximum variation per second of the oil temperature, above which the system will report an alarm
and stop the compressor (this parameter is significant only if the temperature sensor is enabled).
.
−Maximum alarm pressure: determines the maximum pressure above which the system will report an alarm and stop the
compressor (this parameter is significant only if the temperature sensor is enabled).

−Maximum settable pressure: determines the maximum pressure settable as the no-load pressure set point (this parameter is
significant only if the temperature sensor is enabled).

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−No-load time: determines the delay (in seconds) between the time the load solenoid valve is de-energized upon reaching the
desired pressure and the time the motor stops.

−Shutdown delay time: determines the compressor shutdown delay when pressing RESET; when the compressor is on, the
solenoid valve is de-energized (if found energized) and the motor keeps running until the delay is over.

−Pressure sensor enable: enables either the analog pressure sensor or the electromechanical pressure switch (one excludes the
other).

−Temperature sensor enable: enables either the analog temperature sensor or the electromechanical thermostat (one excludes the
other).

−Automatic start enable: enables automatic restarting: if enabled the compressor restarts automatically after a power failure; initial
start-up is still achieved by pressing the START (I) key on the panel.

−Internal phase sequence enable: enables either the board’s internal phase sequence or the phase sequence of an external device.

−Remote enable: enables REMOTE OFF, by which the controller can be bypassed by the external Remote contact.

−No-load pressure set point: indicates the residual pressure required for the compressor to start: the maximum settable value is
determined by the parameter “Maximum settable pressure”.

−Load pressure set point: indicates the operating pressure at which the compressor stops; the maximum settable value is fixed at
0.5 bar lower than the “No-load pressure set point”.

−Unit of measurement: lets you select the unit of measurement for the pressure (bar or psi).

−Oil hours left: indicates the number of hours left before oil maintenance is due; when the count reaches zero the display will show
a maintenance code (see “Maintenance Warnings”). The counter is updated every hour of compressor operating time.

−Oil filter hours left: indicates the number of hours left before oil filter maintenance is due; when the count reaches zero the
display will show a maintenance code (see “Maintenance Warnings”). The counter is updated every hour of compressor operating
time.

−Air filter hours left: indicates the number of hours left before air filter maintenance is due; when the count reaches zero the
display will show a maintenance code (see “Maintenance Warnings”). The counter is updated every hour of compressor operating
time.

−Oil separator hours left: indicates the number of hours left before oil separator maintenance is due; when the count reaches zero
the display will show a maintenance code (see “Maintenance Warnings”). The counter is updated every hour of compressor
operating time.

−Total hours: shows the total number of hours during which the compressor was powered; can be changed.

−Motor hours: shows the total number of hours during which the motor was running; can be changed.

−Reset parameters: this function is for quickly configuring the board to the type of unit on which it is to be installed. There are 2
settings, one for coaxial units and one for belt units. The default value is 0; set it to 1 to configure the board for Coaxial units (see
Tab. 2) or to 2 for Belt units (see Tab. 2). The settings will be updated when leaving the menu (Factory or Service). By default, the
controller is configured to work with Coaxial units.

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PARAMETER DEFAULT DEFAULT [...]

Coaxial Belt
Oil temperature pre-alarm (delta) 5 5* °C
Maximum oil temperature 110 110* °C
Minimum oil temperature -7 -7* °C
Fan starting temperature 80 80* °C
Thermal drift 5 5* °C/sec
Maximum alarm pressure 13.7 13.7* bar
Maximum settable pressure 11.0 11.0* bar
No-load time 75 75 sec
Shutdown delay time 35 35 sec
Pressure sensor enable 1 0 No/Yes
Temperature sensor enable 1 0 No/Yes
Automatic start enable 0 0 No/Yes
Internal phase sequence enable 1 0 No/Yes
Remote enable 0 0 No/Yes
Oil hours left 2000 4000 Hours
Oil filter hours left 2000 4000 Hours
Air filter hours left 2000 2000 Hours
Oil separator hours left 4000 4000 Hours
Total hours ------** ------** Hours
Motor hours ------** ------** Hours
No-load pressure set point 10.0 10.0* bar
Load pressure set point 8.5 8.5* bar
Unit of measurement 1 1* [psi/bar]
Tab. 2 Default parameters for type of compressor

* Parameters that are not used when the sensors are disabled
**The number of hours remains unchanged

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User Menu
The User Menu (see Tab. 3) can be accessed only when the compressor is off; to access the menu, press the FUNCTION key for at
least 5 seconds.

No. PARAMETER MIN DEFAULT MAX [...]

U0 No-load pressure set point 0.5 10.0 15.0 bar
U1 Load pressure set point 0 8.5 * bar
U2 Unit of measurement 0 1** 1 psi/bar
Tab. 3 User Menu for setting parameters
* the maximum value for the load pressure set point is the no-load pressure set point – 0.5bar
** 1=bar, 0=psi

Service Menu
The Service Menu (see Tab. 3) can be accessed only when the compressor is off or during an alarm situation; to access the menu,
press FUNCTION + RESET for at least 5 seconds, after which you will be asked to enter the password.
The password is 2954.

No. PARAMETER MIN DEFAULT MAX [...]

A0 Fan starting temperature 0 80 150 °C
A1 No-load time 30 75 900 sec
A2 Shutdown delay time 30 60 900 sec
A3 Pressure sensor enable 0 1* 1 No/Yes
A4 Temperature sensor enable 0 1* 1 No/Yes
A5 Automatic start enable 0 0* 1 No/Yes
A6 Internal phase sequence enable 0 1* 1 No/Yes
A7 Oil hours left 0 2000 65536 Hours
A8 Oil filter hours left 0 2000 65536 Hours
A9 Air filter hours left 0 2000 65536 Hours
A10 Oil separator hours left 0 4000 65536 Hours
A11 Total hours ------** ------** Hours
A12 Motor hours ------** ------** Hours
A13 Reset parameters** 0 0 2 No/R_Pres/R_on_off
A14 Enable remote 0 0* 2 No/R_Pres/R_on_off
Tab. 4 Service Menu for setting parameters
* 1=R_Pres, 2=R_on_off, 0=not enabled
** Function for setting the default parameters according to the type of unit on which the board is to be
installed: Coaxial (Reset parameters =1) or Belt (Reset parameters =2)

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Factory Menu
The Factory Menu (see Tab. 5) can be accessed only when the compressor is off or during an alarm situation; to access the menu,
press FUNCTION + RESET for at least 5 seconds, after which you will be asked to enter the password.

No. PARAMETER MIN DEFAULT MAX [...]

F0 Oil temperature pre-alarm (delta) 1 5 20 °C
F1 Maximum oil temperature 0 110 150 °C
F2 Minimum oil temperature -14 -7 0 °C
F3 Fan starting temperature 0 80 150 °C
F4 Thermal drift 1 5 10 °C/sec
F5 Maximum alarm pressure 0 13.7 16.0 bar
F6 Maximum settable pressure 0.5 11.0 15.0 bar
F7 No-load time 30 75 900 sec
F8 Shutdown delay time 30 60 900 sec
F9 Pressure sensor enable 0 1* 1 No/Yes
F10 Temperature sensor enable 0 1* 1 No/Yes
F11 Automatic start enable 0 0* 1 No/Yes
F12 Internal phase sequence enable 0 1* 1 No/Yes
F13 Remote enable 0 0* 1 No/Yes
F14 Oil hours left 0 2000 65536 Hours
F15 Oil filter hours left 0 2000 65536 Hours
F16 Air filter hours left 0 2000 65536 Hours
F17 Oil separator hours left 0 4000 65536 Hours
F18 Total hours 0 ------** 65536 Hours
F19 Motor hours 0 ------** 65536 Hours
F20 Reset parameters*** 0 0 2
Tab. 5 Factory Menu for setting parameters
* 1=enabled, 0=not enabled
** the value is the one used for the unit
*** Function for setting the default parameters according to the type of unit on which the board is to be
installed: Coaxial (Reset parameters =1) or Belt (Reset parameters =2)

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Maintenance warnings
The compressor is equipped with 4 counters that count down every hour of motor running. When a counter reaches zero, the display
shows a message informing that the compressor needs servicing. No parameter (pressure, temperature, total hours, motor hours) can
be viewed on the display until the warning message is reset from the Service Menu (see Tab. 5).
If multiple maintenance warnings occur at the same time, the warnings are shown on the display in sequence.

ALARM DESCRIPTION
CH1 Oil hours left
CH2 Oil filter hours left
CH3 Air filter hours left
CH4 Oil separator hours left
Tab. 6 Maintenance warnings

In addition to the indication on the display panel maintenance is indicated even by the LED

Alarms
Alarms are shown by code messages that appear on the display and by red LEDs that light up beneath them.
There are 11 kinds of alarms, 6 of which are shown on the display (see Tab. 6). If multiple alarms occur at the same time, the
messages are shown on the display in sequence.
All alarms make the compressor stop; the compressor can be restarted only after the cause of the alarm has been removed. The
alarm messages remain displayed visible even after their cause has been removed; to cancel the message you need to press RESET.
The presence of water is checked every time the controller is powered on and every time the motor is stopped or on standby for
more than 5 minutes. The first 10 times the presence of water is detected, the warning is given only by the flashing of the respective
red LED; the 11th time, the compressor will stop until the water is removed.
The Service Menu and the Factory Menu remain accessible.

ALARM DESCRIPTION
Indicates a faulty connection to the power mains (1)
Means that the motor’s maximum temperature has been exceeded (1)
Means that the maximum oil temperature has been exceeded (if the pressure sensor is enabled, the pre-alarm is
indicated by a flashing LED but the compressor remains in operation)

Means that there was a power failure the last time the compressor was used. The unit remains in operation. To
cancel the warning, press RESET with the compressor off. (this alarm works only if Automatic Start is not
enabled).
AL1 Indicates a faulty or broken temperature sensor (if enabled)
AL2 Indicates a faulty or broken pressure sensor (if enabled)
AL3 Indicates a missing phase or means that the phase sequence transformer is not working (if the internal phase
sequence is enabled)
AL4 Means that the pressure has reached the maximum alarm threshold (if the pressure sensor is enabled)
AL5 Means that the temperature is rapidly rising above the preset thermal drift (if the temperature sensor is enabled)
AL6 Means that the emergency button was pressed
1) If it’s present this alarm only, appear on display any horizontal lines.
Tab. 7 Alarm messages

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Connection diagram

Fig. 1 Board layout

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Fig. 2 Connection diagram

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Fig. 3 Diagram showing the proper connection of a new board on the previous wiring layout.

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