
B-63983EN/02 11.PMC ALARM MESSAGES AND ACTIONS TO TAKE
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(3) Timing
"What did you do when the error occurred?"
If the error occurs when you turn on the power, first check
whether each cable connector is connected to the appropriate
device, as well as the assignment data. A system alarm occurs
when the power is turned on, if bases 1 to 3 are assigned while
bases 1 to 3 are actually not connected.
Also, when the master is restarted, the slave needs to be restarted
as well. Check that the power of the slave is off before turning
off the power of the master.
If the error repeats every time you carry out a certain operation,
the likely cause is that an inadequate voltage is applied to the
machine because of loose connector connection, noise,
insufficient power capacity, or DO connection to ground that is
caused by that particular operation.
(4) Operation
"Does the error occur every time you carry out the same
operation?"
If the error occurs every time you carry out the same operation,
you can locate the faulty part by removing the slaves sequentially
starting with the one having the largest group number. Note that
removing certain types of slaves (e.g., operator's panel) leaves
you unable to manipulate the machine. Take necessary
precautions for safety before removing such slaves.
If an error is unrepeatable and occurs with low frequency, its
cause is difficult to identify. In that case, there is no option but
to take every possible measure and see if the error will be
corrected. Such measures include replacing hardware
components (masters, slaves, cables, etc.), strengthening the
power supply (using an independent power source not shared
with other devices), enhancing the earth grounding system,
shielding the cables, and installing the PMC cables and other
cables in separate bundles.