
B-63983EN/02 11.PMC ALARM MESSAGES AND ACTIONS TO TAKE
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A system alarm occurs at a cycle start.
<Category> DO connection to ground
<Configuration>
NC
I/O Unit-A
Group 0
Connection
Group 1
I/O Unit-A
Group 2
I/O Unit-A
Group 3
Operator's
panel I/O
Group 4
<Cause> DO was short-circuited due to a wiring mistake on
the operator's panel.
<Explanation> Some operator's panel I/O modules cause a system
alarm if the DO output is connected to ground. In
this case, we were able to identify the faulty
component by checking the signal which is turned
on at a cycle start on the operator's panel.
A system alarm occurs once every five times the feeder is moved.
<Category> Insufficient power capacity or drop in voltage
<Configuration>
NC
I/O Unit-A
Group 0
<Cause> The power voltage of the slave dropped from 24
volts to 17 volts when the feeder was moved.
<Explanation> If a system alarm is prone to occur in response to a
specific operation, it is highly likely that a drop in
voltage, noise interference, or loose cable
connection results from that operation.