356
Handling Errors and Alarms Section 7-10
ERH Indicator: Lit, RUN Indicator: Not Lit
The unit number for the Analog I/O Unit has not been set correctly.
7-10-4 Restarting Special I/O Units
There are two ways to restart Special I/O Unit operation after having changed
DM contents or having cleared the cause of an error. The first way is to turn
the power to the PLC OFF and ON, and the second way is to turn ON the
Special I/O Unit Restart Bit ON.
Special I/O Unit Restart Bits
If the error is not cleared even after turning the Special I/O Unit Restart Bit ON
and then OFF again, then replace the Unit.
Input data will be 0000 and output will be 0 V or 0 mA during restart.
7-10-5 Troubleshooting
The following tables explain the probable causes of troubles that may occur,
and the countermeasures for dealing with them.
Conversion Data Does Not Change
RUN
ERC
ERH
: Lit
: Not li
Error Error contents Input condition Output condition
Duplicate Unit Number The same unit number has
been assigned to more than
one Unit or the unit number
was set to a value other than
00 to 95.
Conversion does not start
and data becomes 0000.
The output value will be 0 V.
Special I/O Unit Setting Error The Special I/O Units regis-
tered in the I/O table are dif-
ferent from the ones actually
mounted.
Bits Functions
A50200 Unit #0 Restart Bit Turning the Restart Bit for any
Unit ON and then OFF again
restarts that Unit.
A50201 Unit #1 Restart Bit
~~
A50215 Unit #15 Restart Bit
A50300 Unit #16 Restart Bit
~~
A50715 Unit #95 Restart Bit
Probable cause Countermeasure Page
The input is not set for being used. Set the input to be used. 318
The peak value hold function is in
operation.
Turn OFF the peak value hold func-
tion if it is not required.
323
The input device is not working, the
input wiring is wrong, or there is a
disconnection.
Using a tester, check to see if the
input voltage or current is changing.
---
Use Unit’s alarm flags to check for a
disconnection.
326
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