v. 3.0
Reference guide
Compressor Control Module CM-RC-01
3.0
11 / 44
If the CM-RC-01 is locked, an external reset must be performed by either powering off the device
for minimum 5 seconds or sending a reset command on the serial bus.
When power is turned on to the CM-RC-01 module, the PTC resistance is measured:
If PTC resistance
is below the reset limit 2,7 kΩ:
No alarm:
The relays are energized immediately (if no other faults are present)
If PTC resistance is between 2,7 kΩ and 4,5 kΩ:
Alarm:
The relays are
first energized when below 2,7 kΩ
(compressor motor has cooled down)
If PTC resistance is above 4,5 kΩ:
Alarm lock: The relays are not energized and the module is locked
4.2.2
Discharge temperature
A temperature sensor is mounted on the discharge side of the compressor; the CM-RC-01 will
open the relays and break the safety chain if the discharge temperature threshold is exceeded.
The default thresholds for the selected reciprocating compressor are defined in the BEST
software.
4.2.3
Oil supply
Depending on the compressor type, the oil supply monitor is configured for either oil level (OLC-
D1) or oil pressure difference (DP-1) monitoring. Actual status is always accessible via Modbus.
If an
oil level fault
is detected, the status is immediately updated via Modbus. However, the first
90 seconds after compressor start, the fault signal is not activated. If the oil level is still too low,
the CM-RC-01 releases the fault relay and locks out immediately.
The OLC-D1 module (24 V version) must be used for the oil level detection.
A warning signal is set immediately if the compressor is running and the OLC input is open.
If an
oil pressure difference fault
is detected, the status is immediately updated via Modbus. The
first 90 seconds after compressor start, the fault signal is not activated. If the oil pressure
difference is still too low, the CM-RC-01 releases the fault relay and locks out immediately.
Both oil fault alarms must be externally reset by either powering off the device for minimum 5
seconds or sending a reset command on the serial bus.
4.2.4
High pressure handling
A high-pressure switch can be connected to the CN2 of the CM-RC-01. An alarm is set on
CN2:Relay NC and on Modbus if the high-pressure switch opens.
4.2.5
Pressure limits (option)
In the BEST software a low pressure and a high pressure limits can be configured. If one of the
limits are reached, the compressor is stopped and an alarm is issued.
