Part
6
-
Diagnosis and Troubleshooting
Communication wires P Q have short
circuited or disconnected
1
Reconnect the communication wires
Wires between outdoor and MS
communication terminals block are loose
Ensure the wires are connected properly
The sequence of the PQE signal lines is
incorrect.
Reverse the sequence of signal lines.
Interference from high voltage (220V or
higher) wires
Ensure the communication wires and
high voltage wires are separated
Communication wires are close to a
source of electromagnetic radiation such
as transformer or strong fluorescent lamp
Remove the source of interference, or
add additional shielding to the
communication wires
The length of communication wire is over
1200m
Reduce the wire length to less than
1200m
Replace the outdoor main PCB or
communication terminals block resolves
the error
Replace the MS PCB or communication
terminals block
Notes:
1. Measure the resistance among P, Q and E. The normal resistance between P and Q is 120Ω, between P and E is infinite, between Q and E is infinite.