
4. AnSHCPU MODULE
4 - 8
MELSEC-A
Table 4.2 Self-diagnosis
Diagnosis
Diagnosis timing
CPU
module
status
"RUN"
LED
status
LED
display message
Memory error
Instruction code check
When the corresponding instruction is executed
INSTRUCT. CODE
ERR.
Parameter setting check
When power is switched ON or a reset is executed
When switched from STOP/PAUSE to RUN
PARAMETER ERROR
No END instruction
When M9056 or M9057 is switched ON
When switched from STOP/PAUSE to RUN
Stop
Flashing
MISSING END INS.
Instruction execution
disable
When CJ, SCJ, JMP, CALL(P), FOR and NEXT
instruction is executed
When switched from STOP/PAUSE to RUN
CAN'T EXECUTE (P)
Format
(CHK instruction) check
When switched from STOP/PAUSE to RUN
CHK FORMAT ERR.
Instruction execution
disable
When an interrupt occurs
When switched from STOP/PAUSE to RUN
CAN'T EXECUTE (I)
CPU error
RAM check
When power is switched ON or a reset is executed
When M9084 is switched ON during STOP
RAM ERROR
Operation circuit check
When power is switched ON or a reset is executed
OPE. CIRCUIT ERR.
Watchdog error check
When an END instruction is executed
Stop
Flashing
WDT ERROR
END instruction not
executed
When program processing reaches the end of the
program
END NOT EXECUTE
Endless loop execution
At any time
WDT ERROR
I/O error
I/O module verify
When an END instruction is executed
(Not checked when M9084 is ON)
Stop
Flash-
ing
UNIT VERIFY ERR.
Fuse blown
When an END instruction is executed
(Not checked when M9084 is ON)
Run
ON
FUSE BREAK OFF.
Special function module
error
Control bus check
When a FROM, TO instruction is executed
CONTROL-BUS ERR.
Special function module
error
When a FROM, TO instruction is executed
Stop
Flashing
SP. UNIT DOWN
Link module error
When power is switched ON or a reset is executed
When switched from STOP/PAUSE to RUN
LINK UNIT ERROR
I/O interruption error
When an interruption occurs
I/O INT. ERROR
Special function module
assignment
When power is switched ON or a reset is executed
When switched from STOP/PAUSE to RUN
SP. UNIT LAY. ERR.
Special function module
error
When a FROM, TO instruction is executed
Stop
Run
Flash-
ing
ON
SP. UNIT ERROR
Link parameter error
When power is switched ON or a reset is executed
When switched from STOP/PAUSE to RUN
Run
ON
LINK PARA. ERROR
Battery error
Battery low
At any time (not checked When M9084 is ON)
Run
ON
BATTERY ERROR
Operation check error
When the corresponding instruction is executed
Stop
Run
Flash-
ing
ON
OPERATION ERROR
Содержание A1SH
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