DXM Control PCB

The DXM controller has all of the functionality of the CXM but with additional inputs, outputs and features to give maximum flexibility. Like the CXM this is available in standard, Lonworks or MPC Multi Protocol (BACnet, JCI N2 or Modbus) formats.

Additional Features for DXM over CXM

The additional features provided by the DXM controller, over and above the standard CXM are

a. Removable thermostat connector.
b. Night setback control.
c. Random start on return from night setback.
d. Minimized reversing valve operation (Unit control logic shall only switch the reversing valve when cooling is demanded for the first time. The reversing valve shall be held in this position until the first call for heating, ensuring quiet operation and increased valve life.).
e. Override temperature control with 2-hour timer for room occupant to override setback temperature at the controller.
f. Dry contact night setback output for digital night setback controllers.
g. Ability to work with heat pump or heat/cool (Y, W) type controllers.
h. Ability to work with heat pump controllers using O or B reversing valve control.
i. Emergency shutdown contacts.
j. Boiler less system heat control at low loop water temperature.
k. Ability to allow up to 3 units to be controlled by one controller.
l. Relay to operate an external damper.
m. Ability to automatically change the fan speed when using a multistage controller
n. Relay to start a system circulation pump

The DXM controller is shown above.

The system can be put into a test mode by shorting the TEST terminals and the unit then goes into a 20 minute test mode where all of the time delays are increased by 15 times. The alarm relay will cycle during test mode showing the last registered fault. The Test LED will light during test mode. You can prematurely exit test mode by shorting the Test mode for 3 seconds during a test. You can also enter and exit test mode by cycling the G fan input three times in a one minute period.

The dip switch combinations are shown above

These are the alarms and operation codes.

This shows what each terminal does.

The normal thermostat connection is shown below

The digital connection for DXM2 is shown below