pLAN is the communication wire between unit 1 and unit 2 controller board. The units will act independently when the communication is lost.


Possible Cause
Component to Check
Recommended Action
Single unit configurationSYS under E menuChange setting from 2 to 1
Loose connector
pLAN connector on J6 block at each controller board
Push in connector
Incorrect Controller Address
CAD under E menu. CAD must be 1 for unit 1 and 2 for unit 2
Correct setting. Move the display connector (J7) to unit 2 to configure unit 2 address
Controller board failure/power loss
24VDC on across J1
Power supply LED light between J8 and J9 should be lit
Secure power input connector.
Replace controller board is power is present but controller board does not power on. Refer to the Controller board LED status chart below.

Controller board LED status

Power Supply LED (Yellow) 


Indicates power supply to the module

Status LED





Cannot identify other unit through pLAN: Loose pLAN connection OR wrong controller address

Software error: No pLAN address set

Module operating correctly with pLAN