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Chapter 5 Power Supply / CPU
5-23
5.6 Functions
5.6.1 Self-diagnosis
1) Functions
(1) The self-diagnosis function permits the CPU module to detect its own errors.
(2) Self-diagnosis is carried out when an error occurs during PLC power supply is turned on or operating process.
If an error is detected, the system stops operation to prevent faulty PLC operation.
2) WDT (Watch dog timer) function
The watch dog timer is an internal timer of a PLC to detect the error of hardware and a sequence program. it is
changeable with parameter setting.
The CPU resets the watch dog timer before step 0 is executed (after the END processing is finished). When the END
instruction has not been executed within the set value due to an error occurred in the PLC or the delay of a sequence
program, the watch dog timer will times out. When a watch dog timer error is occurred, all outputs of the PLC are turned
OFF, and the ERR LED of the CPU will flickers. (RUN LED will be turned OFF) Therefore, when use FOR ~ NEXT or
CALL instruction, insert WDT instruction to reset the watch dog timer.
Refer the MASTER-K programming manual for details on the parameter setting.
3) I/O module check function
Mounting conditions of the loaded module are checked
4) Error history
When error occurs, Corresponding error code is stored in special relay F006.
0
WDT
END
0
END
WDT Reset
WDT Reset
WDT Reset
Содержание MASTER-K 120S Series
Страница 26: ...Chapter 4 Names of Parts 4 3 2 K7M DRT60U 3 K7M DT60U 4 1 2 40 points main unit Standard 1 K7M DR40U ...
Страница 27: ...Chapter 4 Names of Parts 4 4 2 K7M DRT40U 3 K7M DT40U 4 1 3 30 points main unit Standard 1 K7M DR30U ...
Страница 28: ...Chapter 4 Names of Parts 4 5 2 K7M DRT30U 3 K7M DT30U 4 1 4 20 points main unit Standard 1 K7M DR20U ...
Страница 29: ...Chapter 4 Names of Parts 4 6 2 K7M DRT20U 3 K7M DT20U 4 1 5 30 points main unit Economic 1 K7M DR30UE ...
Страница 138: ...Chapter 7 Usage of Various Functions 7 54 c Program ...
Страница 306: ...Appendix 3 External Dimensions App3 2 2 Slim type G7E DC08A G7E RY08A G7F ADHB G7F DA2V G7F RD2A ...