Troubleshooting Binary Output (Relay Output) - Trane Tracer MP503 Installation, Operation And Maintenance Manual

Troubleshooting Binary Output (Relay Output)

If a binary output (relay output) is not turning on the equipment wired to it, then follow the
troubleshooting steps in
The troubleshooting steps assume the equipment connected to the binary output is OFF when it
is believed to be ON and vice versa when it should be OFF.
Table 14. Binary output (relay output) troubleshooting of external wiring
Step Number Action
Perform the initial troubleshooting steps described in
Step 1
board operation is functioning.
Inspect the wiring. Is there a good connection between the wire and the terminal blocks? Look
Step 2
for shorts or opens. Pay particular attention to wire splices.
Look at the status LED for the binary output you are troubleshooting. If the LED is ON, the
MP503 is energizing its output relay.
Use volt meter (set to measure ac voltage) to measure the voltage across the binary output
terminals on the MP503.
Step 3
If the voltage is approximately 24 V, the problem lies beyond the MP503. Is the wiring to the
equipment good? Is there a pilot relay and is it functioning correctly? Is a Hand-Off-Auto (HOA)
switch overriding the equipment?
If the voltage is approximately 0 V, proceed to the next step.
Remove the wires from the binary output terminals and measure the voltage again.
If the voltage is 24 V, there is a wiring or equipment problem external to the MP503.
Step 4
If the voltage is still approximately 0 V, the MP503 is commanding the output to be OFF and
further investigation is required. Refer to
operation of the binary output.
Table 15. Binary output (relay output) troubleshooting of configuration and operation
Step Number
Connect the Rover service tool to the LonTalk communication link, start the Rover service tool,
and select the MP503 from the Active Group Tree. The device plug-in for the selected MP503
Step 1
appears with the Status screen displayed in the workspace.
For more details, refer to the Rover Operation and Programming Guide (EMTX-SVX01).
Select the Bindings button to view the Network Variable Bindings Summary screen for the
LonTalk network that includes this MP503. (The Bindings button will be disabled if the MP503
is the only device currently on the network.) Is this binary output bound? Is it bound to more
than one network device? If it is bound to two devices, one may be commanding the binary
Step 2
output on while the other commands it off.
For more information about network bindings, refer to the section,
p. 13.
If the binary output is correctly bound to another device, is that device communicating? If it
has not communicated for at least 15 minutes, the binary output will go to its communication
Step 3
loss position. The communication loss position is configurable using the device plug-in. Proceed
to the next step to view or edit the communication loss position of the binary output.
To view the communication loss position of the binary output, select the Close button to return
to the Status screen. Press the Configuration button, then select the Outputs tab.
The communication loss position for a binary output can be set to On, Off, or Last State. For
Step 4
example, if you expect the equipment controlled by the binary equipment to be on but it is off
because of the communication loss position, you may want to change the communication loss
position from Off or Last State to On.
24
Table 14. Perform the steps in the order they are listed.
Table 13, p. 23
Table 15 to troubleshoot the configuration and
Action
"Network Variable Bindings,"
Probable Cause
and verify that general General board
problem.
Wiring problem.
Wiring problem.
Wiring problem.
Probable Cause
—
Bindings problem.
Network
communications
problem.
Incorrect
communication loss
position.
CNT-SVX09E-EN