Chapter 6 Function of CPU Module
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6.1.2 I/O Module Check Function
This function is to check the error state of I/O module at the time of start or during operation.
1) In case that the module different from parameter setting is built-in at the time of start or it occurs the error
or
2) In case I/O module is removed or occurs the error during operation,
the error state is detected and warning lamp (ERR) in front of CPU module and then CPU stops to operate.
6.1.3 Battery Voltage Check Function
If battery voltage falls less than memory backup voltage, CPU module detects it and informs of it. The warning
lamp(BAT) in front of CPU module shall be ON.
For further information, please refer to “4.3.3 Durability of Battery”.
6.1.4 Error History Save Function
CPU module has the function that records the error history and analyzes the cause of the error to take a
proper action if the error occurs. (Refer to 6.6.1 Error History)
This is the function to save each error code in special relay F0006.
Notes
All results of self-diagnosis shall be recorded in ‘F’ device area.
For further information of self-diagnosis comments and error actions, please refer to Chapter 12
Trouble shooting, 12.5 Error Code List.
6.1.5 Troubleshooting
1) Classification of Error
The error occurs by PLC itself error, error in system configuration or error detection from operation results.
The error is classified by heavy error mode that stops the operation for the system safety and light error
mode that informs of the error occurrence warning to the user and continues the operation.
The error causes of PLC system is as follows.
y
PLC hardware error
y
Error in system configuration
y
Operation error during user program proceeding
y
Error detection by external device failure
2) Action Mode in case that Error Occurs
If error occurs, PLC system records the error comments in flag and stops to operate or continues the
operation according to error mode.
