6
The WPLLD pressure transducer transmits pressure readings on
the 220 Vac STP power lines. The readings are transmitted in
short bursts (1/2 second) every eight seconds. After four min-
utes, the transducer stops transmitting. A WPLLD Comm Alarm
is posted when the transmission is not received or when noise
interferes with the reception.
PROBABLE CAUSES:
No transmission
1.
No Power to the STP (circuit breaker Off).
2.
STP contactor permanently stuck On.
3.
Controller Module has blown fuse.
4.
Controller Module faulty.
5.
AC Interface Module faulty.
6.
Bad connection from the 220 Vac line to the AC Interface
Module.
7.
Comm Module faulty.
8.
Bad connection between the AC Interface Module and
Comm Module.
9.
WPLLD transducer faulty.
10. Field wiring to STP faulty.
11. STPs using different legs of 3-phase power.
Noise Interference
1.
External device generating noise on the AC line (common
sources are neon signs, variable speed motors, and STP
contactors).
2.
Signal strength adjustment incorrect (Refer to Manual
576013-923).
3.
A sticking STP contactor on one of the lines.
COMM ALARM (WPLLD Only)
