Eliwell EWCM 4120, Manual, Page: 31 / 75

31
COMPRESSOR CONTROL
The device can be configured to manage an inverter compressor or one or more homogenous digital compressors
(max. 4) by setting parameter CP22:
Parameter Description Min Max Notes
CP22
Number of compressor steps
per circuit
0 4
0=inverter compressor.
≠ 0=CP22 represents the number of digital
compressors.
With digital compressors it is also possible to define the number of power stages by setting parameters CP23, CP24
and CP25:
Parameter Description Min Max Notes
CP23 Number of compressor steps 1 1 4
1=whole compressor
≠ 1= CP23 - 1 is the number of Power stages.
CP24 Number of compressor steps 2 1 3
1= whole compressor
≠ 1= CP24 - 1 is the capacity step
CP25 Number of compressor steps 3 1 2
1= whole compressor
2= the number of Power stages is 1
Regulation is proportional or Neutral Zone (ZN) as a function of the inlet probe (temperature or pressure control).
In the case of pressure regulation, probe AI3 must be used (high resolution probe).
In local or remote OFF the compressors are switched off.
The compressors and/or relative Power stages can be directly connected to the controller via the Triac output or relay
or indirectly connected via an external module (connected to controller via an PWM or analogue output):
 Direct Triac TC output.
 Indirect “PWM” output AO1, AO2 (needs external module for piloting the inverter compressor).

Indirect 4..20mA / 0..20mA / 0..10Vcc output AO3 (needs external module for piloting inverter compressor).
 Relay output for piloting digital compressors (whole or segmented).
 Digital Output DO5 (Open Collector) using an external relay.