TM 10-4610-310-14
UNIT MAINTENANCE
LIGHTWEIGHT WATER PURIFIER
TROUBLESHOOTING PROCEDURES
PROGRAMMABLE LOGIC CONTROL (PLC)
GENERAL
The table lists the common malfunctions that you may find during the operation or maintenance of the
Lightweight Water Purifier (LWP) Programmable Logic Controller (PLC) used in the control module assembly.
PLC has 24 input lights on front. The input lights are labeled IN and numbered 0 through 23. Input lights are
energized when 120 VAC is applied at the input terminal with corresponding number as the light. You should
perform the tests/inspections and corrective actions in the order listed.
The PLC output cards relays the signal from the PLC to the component.
This manual cannot list all malfunctions that may occur, nor all tests or inspections and corrective actions. If a
malfunction is not listed or is not corrected by listed corrective actions, notify your supervisor.
MALFUNCTION
TEST / INSPECTION
CORRECTIVE ACTION
There are three commons associated
Tighten loose connection. Replace
with the inputs. AC COM0 is for inputs
or repair broken wires and
0 through 3, AC COM1 is for inputs 4
connections.
through 7, and AC COM2 is for inputs
8 through 23. Make sure commons are
properly connected by testing
commons to wire 2 for 120 VAC.
1. PLC power light
If power light is not on, then PLC is not
If 120 VAC power is available and
receiving power at VAC L1 terminal
PLC power light is not on. Turn the
and VAC NEUT terminal. Measure
power off and back on. If condition
voltage across these terminals (120
persists, remove and replace PLC.
VAC)
If run light on front of PLC is de-
Turn the power off and back on. If
2. PLC RUN light.
energized then PLC is not executing
condition persists, remove and
LWP program.
replace PLC. (WP 0102 00)
If fault light on front of PLC is de-
energized then PLC is not in fault. If
Turn the power off and back on. If
fault light is flashing red then an
condition persists, remove and
3. PLC FAULT light.
application fault has been detected and
replace PLC. (WP 0102 00)
LWP program will not run. If fault light
is solid red then controller hardware
faulted and LWP program will not run.
If RUN, FORCE, and FAULT lights on
Replace PLC. (WP 0102 00)
4. PLC RUN, FORCE, AND
front of PLC are all flashing, this
FAULT light flashing.
indicates that the PLC has an
operating system fault.
5. PLC output Card 1 and 2 no
With power off, measure for voltage
Tighten any loose connections.
power
(120 VAC) at connections (VAC 0) and
(VAC 1).
Inspect the connection
0069 00-1
