Hitachi LQZ700, User Manual

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5 MAINTENANCE
5-4
5.2.2 Trouble detection and solution
(1) Causes of the failure in SYS SW module operation
The causes of the failure in SYS SW module operation are as follows. When one of these
causes is applicable to the case, take a measure according to Action.
Table 5-2 Causes of the Failure in SYS SW Module Operation and Action To Be Taken
Cause of failure in operation Action
The ERR LED comes on. • The external power supply (100 VAC (50/60 Hz) or 100
VDC) is not connected correctly. According to “3.4
Wiring,” connect it correctly.
• Wiring is not performed correctly. According to “3.4
Wiring,” perform wiring correctly.
• The ladder program run switch “LADDER” of the LPU is
not set to “RUN.” Set the ladder program run switch
“LADDER” to “RUN.”
• The “PI/O OK signal” of the PI/O output has changed
from ON into OFF. Find out the cause of OFF and take a
measure. (See “The PI/O OK output has changed from
ON into OFF” in the following field.)
• The LPU is faulty. (PCs OK is not output.) Investigate
the LPU status and take a measure.
The PI/O OK output has changed
from “ON” into “OFF.”
(The ERR LED comes on, too.) • The LPU is faulty. Investigate the LPU status and take a
measure.
• Application error. Find out the cause of the application
that turns off PI/O OK and take a measure. (If PI/O OK
has not been turned on yet, this is not applicable to the
case.)
The ERR LEDs of both systems A
and B blink. • The PRIORITY setting switches of both systems A and B
are set to “1st.” Set one of them to “2nd.”
Though the running system has
broken down, it is not changed
over to the standby system. • The external power supply (100 VAC (50/60 Hz) or 100
VDC) is not connected correctly. Connect it correctly
according to “3.4 Wiring.”
• Wiring is not performed correctly. Perform wiring
correctly according to “3.4 Wiring.”
• The LPU is faulty. (PCs OK is not output.) Investigate
the LPU status and take a measure.