KIMA00H1 (0204)
29
5.2.2
PLC Status
LED’s
(Figure 29)
The PLC is provided with LED's to assist in monitoring operational
status of the processor, PLC inputs and outputs, and expansion
modules.
8 LED’s are provided for monitoring CPU status:
a. POWER LED is on when control power is on to the PLC base
power supply. If LED is off check external power supply and fuses.
b. RUN LED is on when the PLC is operating normally and the
installed program is running. If LED is off, the PLC is inoperable.
Check that the
RUN-REM-PROG
switch is in the RUN position.
c. FAULT LED is on when a program operation or hardware problem
occurs in the PLC. Cycle power to the control panel to “reboot” the
PLC. If this fails to clear the problem, contact the factory.
d. FORCE LED is used during program development and should be
off. Contact the factory if this LED is on.
e. BAT LO LED is on when PLC battery has discharged. New battery
needs to be installed.
f. COMM 0 LED flashing indicates activity on communication port 0.
g. DCOMM LED on indicates PLC default to communication port 0.
h. COMM 1 LED flashing indicates activity on communication port 1,
which is connected to the GT Terminal.
5.2.3
PLC
Inputs
(Figure 29)
During normal operation input LED's are on only if the input is
receiving a voltage signal from an external control device. The PLC
program does not control the operation of these indicators. These
LED’s may be on even if the PLC is not operating.
To troubleshoot suspected input problems measure the DC voltage at
the input terminal referenced to 0V at the power supply (figure 30). If
+24 volts DC is measured the LED for that input should be on, if the
LED is off then the input is defective. If no power is measured at an
input the LED should be off, if the LED is on then the input is
defective.
5.2.4
PLC
Outputs
(Figure 29)
During normal operation output LED’s will be on when the PLC
operating program directs an output to energize. This is not an
indication that the output is operating. All LED’s, and their indicated
outputs, will be off if the PLC is not operating.
To troubleshoot suspected output problems measure the DC voltage
at the output terminal referenced to 0V at the power supply (figure 30).
If the LED for an output is on, then +24 volts DC should be present, if
no power is measured then the output is defective. If +24 volts is
measured when the LED is off, then the output is defective.
This applies to outputs on the base unit and the expansion module.
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