Trane ReliaTel - COMM3;4 Interface Operation & Troubleshooting; Wiring; Leds; Communication Problems

86 RT-SVD03G-EN
COMM3/4 Interface Operation & Troubleshooting
Wiring:
The COMM3/4 board communicates with the RTRM via the MODBUS link using the harness,
labeled 4366-1151. The connections to the board are shown below.
Communication wires must be twisted/shielded as specified by the BAS system being applied. Do
not attach the shield to the COMM3/4 board. It must be taped back to prevent it from touching the
unit.
LED’s:
Amber receive (RX) LED: Blinks whenever communication is occurring with any device. This tells
the service technician that the BAS system is communicating or trying to communicate with other
devices as well as this one.
Green transmit (TX) LED: Blinks once every several seconds, sometimes up to 45 seconds between
blinks, when the unit is sending data to the BAS system. This tells the service technician that this
unit is communicating information to the BAS system. When the TX LED is blinking, the unit is
communicating.
Communication problems:
Won’t communicate with Tracker 3-25 Ton only
• Harness, labeled 4366-1151, must be plugged into RTRM correctly – see previous page.
• Com Link board must be in “ISOLATED COM 3” position. If it is in the wrong position or not
installed, the unit will not communicate.
• Each unit must have a unique address by setting the DIP switches according to the IOM. If 2 units
have the same address, neither will communicate. If the unit has a DIP switch setting other than
the ones specified in the IOM, Tracker will not recognize it.
• Once the unit communicates with Tracker, the Tracker panel will automatically recognize the
unit.
• Resistor missing at last unit in daisy chain (depending on length of line run).
Figure 53. Troubleshooting Outline
COM LINK board
shown in
"Non-isolated
COMM3 or
COMM4 position"
Communication
wiring
DIP Switches
LED's
Shield
taped
back
COM LINK board shown
in "Isolated COM 3"
position
To options
module &
economizer
Zone Sensor
used with
Tracker and
Tracer
Setpoint
Zone
temperature
RTRM
J4
This harness
labeled 4366-1151,
is supplied with the
COMM3/4 interface
J1
J2
TB1
TB1
TX RX