Troubleshooting
122
Doc No: UMAN\FL\0110
Rev. No.: 1.02B
The errors in the PLC can be categorized as below:
1. CPU error:
a. System watchdog Reset (WDT Error)
If there is error in this category the CPU error flag ( MW01_0 device) sets along with corresponding device of
the error. So for WDT error MW01_11 device sets.
2. I/O Error:
a. I/O mismatch error
b. I/O bcc error.
If there is error in this category the I/O error flag ( MW01_1 device) sets along with corresponding device of
the error. So for I/O mismatch error MW01_13 device sets and for I/O bcc error MW01_15 device sets.
3. Program Error:
a. Scan Time Over error
If there is error in this category the I/O error flag ( MW01_2 device) sets along with corresponding device of
the error. So for Scan Time Over error MW02_1 device.
4. Other Errors:
a. Clock calender error
b. Retentive Data Loss error
For Clock calender error MW01_5 device sets and for Retentive Data Loss error MW01_6 device sets
Above error conditions are checked either in each main loop scan or only at power up. This is mentioned in the
following table.
The configuration devices (M) and configuration registers (MW) are used for special purposes.
Error Messages and related information:
No.Event Info1 Info 2 Info 3 Info 4 Special Meaning and Check at
Device countermeasures
1 Retentive MW01_6 In the power-up initialization, Only Power-On
Data Loss data invalidity of RAM (back-
Error up area) has been detected.
If retentive registers are used,
these validity are not guarant-
eed. (No error down)
2 Clock-cal- MW01_5 The data of built-in calendar Only Power-On
endar error LSI is illegal.(No error down)
Set the date and time.
4 I/O slot Unit MW01_1 The I/O allocation information Only Power-On
mismatch No. Type MW01_13 and the actual I/O configuration
are not identical.(Error down)
Check the I/O allocation and
the option card mounting status
5 I/O BCC Unit Register MW01_1 I/O bus parity error has been Each main loop
error No. No. MW01_15 detected in data read/write for scan
I/O modules. An abnormality
has been detected in I/O bus
checking. (Error down)I/O No
answer. (Error down) Check
the expansion cable connect-
ion and the I/O module mounting
status.
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