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8.2 Error Clear
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8.2 Error Clear
In a redundant system, the errors that continue the CPU module operation can be cleared.
The following methods for error clear are available in a redundant system.
• Clearing the host CPU module error
• Clearing the standby system CPU module error by the control system CPU
module
(This includes clearing the standby system CPU module error by GX Developer
connected to the control system CPU module.)
(1) Clearing Host CPU Module Error
The host CPU module error can be cleared using a special relay (SM50) and a special
register (SD50).
(a) Procedure
Error clear is performed according to the following procedure.
1) Remove the cause of target error.
2) Store the corresponding error code into a special register (SD50).
3) Turn special relay SM50 from OFF to ON.
4) The target error is cleared.
If the error is cleared and the CPU module returns to normal, the relevant special
relay, special register and LED return to the previous statuses.
If the same error occurs again after that, it will be re-registered in the failure
history.
(b) Cautions
1) When the corresponding error code is stored in SD50 and error clear is
performed, the last digit of the code No. will be ignored.
When multiple errors, of which codes are different in the last digit only, occur,
the errors can be simultaneously cleared.
[Example]
If errors that correspond to error codes 2100 and 2101 occur, both of them
will be simultaneously cleared when either one is cleared.
In the case of errors that correspond to error codes 2100 and 2111, both of
them will not be simultaneously cleared even when either one is cleared.
2) If an error has occurred due to a problem other than that of the CPU module it
will not be removed even when clearing the error is attempted using SM50 and
SD50.
[Example]
The cause of the SP. UNIT DOWN error cannot be removed by performing
error clear operation using SM50 and SD50, as the error could have
occurred in a base unit (including extension cables), intelligent function
module, etc.
Remove the cause of the error by referring to the error code list.
3) If the cause of the error is not removed after error clear has been performed,
the same error will be detected.
