Event History Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

15.4

Event History Function

The CPU module collects and stores event information from each module, such as errors detected by the module, operations
performed on the module, and network errors.
Once errors and operations are stored, they can be checked chronologically. This function helps to determine the causes of
problems that have occurred in the equipment/devices, check the update status of the programmable controller control data,
and detect unauthorized access.
In a redundant system, events that occur in a module on an extension base unit are saved in the event history of the CPU
module of the control system.
However, events that occur in the module on the extension base unit may be saved in the event history of the CPU modules
of both systems when the system is switched by power-off or reset of the control system, depending on the timing of saving.
The information of events that occurred in the host
CPU module and modules which are managed by
the host CPU module are sampled by the CPU
module in a batch and saved.
*1 If the CPU module is operated online using the engineering tool, there are times when processing performed automatically by the
system is saved as an event.
The event history information is constantly collected regardless of the operating state of the CPU module.
There are occasions, however, when the event history information cannot be collected due to a major error in
a module, a base unit error, a cable failure, or some other cause.
* 1
Engineering tool
The event information that is held in the CPU
module is displayed with an engineering tool.
15 RAS FUNCTIONS
15.4 Event History Function
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