
11.PMC ALARM MESSAGES AND ACTIONS TO TAKE B-63983EN/02
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(6) DO connection to ground
With some types of operator's panel, a communication alarm
occurs if the DO terminal is connected to ground or to another
DO terminal due to inadequate cable connection, module
malfunction or failure, or other cause.
(7) Insufficient power capacity or drop in voltage
Check whether the power capacity is insufficient. While the
machine had a sufficient power capacity when originally
designed, it may be suffering a power shortage due to such
factors as subsequent modifications to the machine design and/or
the factory facilities. Also, even if there is no problem under
normal operating conditions, certain operations may result in a
drop in voltage.
(8) Loose power connection
Check that the power cable is connected firmly. Several cases
have been identified in which intermittent errors occur at an
extremely low incidence because the power cable is loosely
connected to the power unit precluding the stable supply of
power to the slave.
(9) Power unit malfunction or failure
A communication error may result from an instantaneous
interruption of power supply due to a malfunction or failure of
the power unit.
(10) Restart of the slave at the time of the CNC restart
When the master I/O Link device is restarted, the slave needs to
be restarted as well. Particular care must be exercised about
intelligent-type slaves (those that exert standalone control
independently, such as FS0-C, Power Mate, b amplifier, and
spindle monitor unit) because, when the power of the master is
turned off, a system alarm is generated in the slave. If the CNC
alone is restarted in this situation, the system alarm in the slave
causes another system alarm to be generated in the master.
(11) System alarm in the slave
In cases where intelligent-type slaves are used, if a system alarm
occurs in any of the slaves, the master also generates a system
alarm. Similarly, if a system alarm occurs in the master, the
slave generates a system alarm as well. Therefore, when such
slaves are used, it is important to know which device (master or
slave) has generated a system alarm first.
If only the master is experiencing a system alarm while no such
alarm is occurring in the slave, the likely cause is that the power
of the slave was turned off instantaneously, causing a system
alarm in the master, and then the slave was restarted.