Mitsubishi 00JCPU, Руководство пользователя

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CHAPTER6 FUNCTIONS
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6.17 Self-d
iagnostic F
unction
6.17 Self-diagnostic Function
(1) Definition
This function allows the CPU module to diagnose itself to check for errors.
This function aims to preventive measures and prevention of malfunction of the CPU module.
(2) Self-diagnostic timing
When an error occurs at power-on or during the RUN or STOP status of the CPU module, the error is detected
and displayed by the self-diagnostic function, and the CPU module stops an operation.
Note that errors cannot be detected by the function depending on error status or an instruction executed.
When the operation is not stopped by the function, configure a safety circuit external to the programmable
controller so that the entire system operates safely.
(3) Checking errors
(a) LED status
When the CPU module detects an error, the ERR. LED turns on.
(b) Storage location of error information and error check
When the CPU module detects an error, the special relays (SM0, SM1) turn on and the error information (error
code) are stored in the special register (SD0).
When several errors are detected, the latest error code is stored in SD0.
Use the special relays and special register in a program as an interlock for the programmable controller and
mechanical system.
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When the Redundant CPU is used, the details of an error occurred in the other system are stored in the special relays
(SM1610 to SM1626) and special registers (SD1610 to SD1636) except when:
• the other system is during off, reset, or hardware failure,
• "WDT ERROR" (error code: 5000, 5001) is detected, or
• tracking cable has an error (not connected, disconnection, or failure).
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The details of the following errors that indicate the CPU module status are not stored in the special relays (SM0 and
SM1) and special registers (SD0 to SD26), and the ERR. LED does not turn on.
The error details are stored in the error history (
Section 6.18).
• System switching from standby system to control system... "CONTROL EXE." (error code: 6200)
• System switching from control system to standby system... "STANDBY" (error code: 6210)
(4) Checking error history
To check the latest error code, select [Diagnostics] [PLC diagnostics] "Error log" in GX Developer.
The error history data are backed up using a battery even after the programmable controller is powered off.