Omron GRT1-ML2 Manual page 15

Setup and usage
4. Attach the new unit to the system. Close the locks on the front of the unit.
5. Turn on the power supplies to the unit.
When replacing a SmartSlice I/O Unit online, note the following things:
• When a unit is removed from the I/O communication, the withdrawn flag
of the unit is set on and the TS LED on the GRT1-ML2 flashes red.
• If I/O power supply of the unit is not turned off, there can be false output
signals, false input signals and electrical schocks.
• Only replace one SmartSlice I/O Unit at a time.
• If a unit is replaced with a different type of unit, there can be unexpected
outputs and the restore operation can be incomplete.
• If the base block has faults or damage, turn off the power supply and
replace the entire unit.
When an online replacement is performed, the status word of the GRT1-ML2
reports an error (missing I/O Unit). When the I/O Unit is replaced or put back,
the status word changes to 8000 hex, but the error has already been
detected by the TJ1-MC__. To avoid this, it is necessary to mask the errors
before the online replacement is performed. To perform the online
replacement do the following:
1. Execute MECHATROLINK(unit,37,station_addr, 0). This masks all
bits, including errors, in the GRT1-ML2 status word.
2. Replace the I/O Unit.
3. Execute MECHATROLINK(unit,37,station_addr, $4000). This sets the
error mask to its default value.
GRT1-ML2 MANUAL 15