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

Event history function

This function collects the event information from each module, such as errors detected by the module and operation
performed to the module, and stores them in the remote head module.
checked chronologically.
Using this function enables the following.
• Investigating the cause of defects in the equipment/device
• Checking the control data update status of the own remote head module and the module being managed by the own
remote head module
• Detecting unauthorized access to the own remote head module and the module being managed by the own remote head
module
*1 If the remote head module is operated online using the engineering tool, processing performed automatically by the system may be
stored as an event history.
• The event history is constantly collected regardless of the operating state of the remote head module. There
are occasions, however, when the event history information cannot be collected due to such an error as a
major error in a module and base unit error.
• The remote head module periodically receives clock data from the master station. If the master station is not
connected to the remote head module, the clock data will not be corrected.
• If the remote head module is powered off and on, the clock will restart from the time of the power-off. (The
clock pauses during power-off) Therefore, the time and date of the event that occurred during initial
processing may be different from the actual time and date. Also, the time and date of event occurrence
already saved in the event history cannot be corrected even if clock data is received from the master
station.
• If the remote head module is powered off when the event history is being written to the flash ROM, the time
when the power was turned off may not be correctly written to the flash ROM. When the module is powered
on, if the time when the power was turned off does not exist in the flash ROM, the time is retrieved from the
occurrence date of the final event stored in the event history. If the time could not be retrieved from the
event history, the clock will restart from the initial value (2000/01/01 00:00:00).
• In a redundant system, the clock of the remote head module in the standby system automatically
synchronizes with that of the remote head module in the control system.
1 FUNCTIONS
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1.5 RAS Function
*1
Once errors and operations are stored, they can be