Mitsubishi Electric MELSEC iQ-R-R00CPU, User Manual

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6 RAS FUNCTIONS
6.2 Self-Diagnostics Function
127
6
6.2
Self-Diagnostics Function
This function (the CPU module itself) checks if a problem exists in the CPU module.
Self-diagnostics timing
If an error occurs when the CPU module is powered on or while it is in the RUN/STOP state, the CPU module detects, and
displays it, and stops operation. However, depending on the error occurrence status or the instruction to execute, the CPU
module may not be able to detect the error. Configure safety circuits external to the programmable controller to ensure that
the entire system operates safely even in such a case.
Check method of error
This section describes the check methods when error occurs.
Check method using the special relay and special register
When the CPU module detects an error, it turns SM0 (Latest self-diagnostic error (including annunciator ON)) and SM1
(Latest self-diagnostic error (not including annunciator ON)) on and stores the error code corresponding to the error definition
in SD0 (Latest self-diagnostics error code). If multiple errors are detected, the latest error code is stored in SD0. Use SM0,
SM1, and SD0 on the program for the CPU module or mechanical interlock. Besides, the error code up to 16 pieces for the
error contents being currently generated will be stored into SD10 to SD25 (Self-diagnostic error number). (The error code for
the error content of 17th piece on and after will not be stored.)
Check method using LED
The error occurrence conditions can be checked through the lighting conditions of ERROR LED. (

MELSEC iQ-R CPU
Module User's Manual (Startup))
Check method using the engineering tool
The error conditions for the overall system, error or event history being currently generated can be checked on the Module
diagnostics window. (
 GX Works3 Operating Manual)
■
Existing errors
Up to 16 errors (description of errors) currently existing in the CPU module can be displayed.
*1
However, even when an
additional error occurs after a stop error, the error information is not updated.
*1 The maximum number of displayable errors is 15 for continuation errors and 1 for stop errors. When 15 continuation errors are displayed
and another one occurs, description of the new error is not displayed. Also, when an error with the same code has already been
displayed, the date and time of occurrence and detailed information of the relevant error are not updated.
■
Error history
Occurred errors is logged in the event history (

Page 136 Event History Function)
The event history is updated only when a battery error occurs, independent of the operating status of the CPU module. Also,
when a battery error is detected after the occurrence of a stop error, the information on existing errors is not refreshed, and
only the event history is updated.
• When using the Process CPU (redundant mode), refer to the following as well.
 Page 435 FUNCTIONS
• When using the SIL2 Process CPU, refer to the following as well.

Page 605 FUNCTIONS
• When using the Safety CPU, refer to the following as well.
 Page 535 FUNCTIONS
RnCPU RnENCPU
RnSFCPU RnSFCPU RnPSFCPU RnPSFCPU RnPCPU RnPCPU
(Standard) (Safety) (Standard) (Safety) (Redundant) (Process)