Technical Section 
DIM does not 
respond to 
network 
communications/ 
Network protocol 
is incorrect. 
Go into INTERFACE menu, NET PROTOCOL item. The 
protocol must match host system. Select correct interface. 
Incorrect network 
address. 
The network address at the building automation system 
and at the DIM must match. The network address must 
be unique for each DIM. 
Verify and/or change polarity of RS-485 A and B wires.  
Data sent to DIM may be in form that the controller cannot 
recognize. 
LonWorks
®
 or 
BACnet
®
 board 
not installed. 
Contact factory for further assistance. 
Bad LonWorks
®
 
or BACnet
®
 
board. 
Contact factory for assistance. 
Foreign network 
acquired 
controller. 
(LonWorks
®
 only) 
Go into CONFIGURE menu, LON item. Select GO 
UNCONFIG option, press the SELECT key. Return to the 
LON item, select the SERVICE PIN option and press the 
SELECT key. Selecting GO UNCONFIG will reset the 
FHC50’s authentication key, allowing the SERVICE PIN 
to install or reclaim the FHC50 to the LonWorks
®
 network. 
Alarm relays do 
not work. 
Enter the Set Points menu. Verify that the alarm that is 
supposed to trigger the relay is not set to 0 (OFF). If the 
alarm set point is zero, alarm relay is not active, so relay 
will not be required to change state.  
Check the wiring from DIM relay's output to the device 
that is connected to the relays. 
Disconnect the wiring (6-pin connector) from relay contact 
pins 1 and 2 for low alarm relay and pins 3 and 4 for relay 
“B”. Go into DIAGNOSTICS menu, ALARM RELAY A or 
ALARM RELAY B. Connect an ohm-meter to relay 
terminals to verify contact open and closes. Press the 
/ key to manually trip the relay. If relay responds 
(contact opens and closes), the device connected is 
incompatible or defective. If relay does not respond, relay 
is defective (may be caused by incompatible device). 
Replace DIM.