Mitsubishi Electric FX5 User Manual page 164

■File size
The size for event history files can be changed in event history setting (Page 160 Event history settings). If the storage
size exceeds the specified size, records are deleted in order from the oldest one and the latest one is stored. An event history
file size is obtained from the following calculation formula.
Event history file size = File header size + Event history management information size + (Number of records × Size per event
history record)
Element
File header size
Event history management information size
Size per event history record
*1 Because the contents of detailed information may differ depending on the event to be saved or the detailed information may include a
variable-length file name, the size per event history record is variable.
The number of events to be saved in the event history file differs depending on the event type to be saved.
■When files are created
An event history file is created when:
• The CPU module is turned off and on (if there is no event history file or after the event history settings are changed).
• The CPU module is reset (if there is no event history file or after the event history settings are changed).
• Initialization of the SD memory card (when no event history file exists)
*1 When a parameter is stored in the data memory, the event history file is created on the SD memory card, according to the event history
setting.
The following table shows how the event history is treated depending on operation.
Operation
Memory initialization
Event history creation
Indicates the operation of the event history for the SD memory which was removed and mounted in case that the save
destination memory is the memory card (SD memory card).
Operation
Removal of the SD memory card
Installation of the SD memory card
■When parameters take effect
Any changed parameters take effect when:
• The CPU module is powered on
• The CPU module is reset
Any changed parameters written in the storage memory with the CPU module in the STOP state does not take
effect when the CPU module operating state is changed from STOP to RUN. In this case, the changed
parameters will take effect the next time when the CPU module is turned off and on or reset.
21 RAS FUNCTIONS
162
21.2 Event History Function
*1
Operation for the event history
When this event occurs, the event history is stored into the internal memory. If the internal memory reaches the
maximum number of event history records it can store, all subsequent events are lost (Page 163 Loss of
event history information).
The event history, which has been stored in the internal memory during absence of the event history file, is stored
into the data memory or the SD memory card (If any event was lost, it is logged as "*HST.LOSS*").
Operation for the event history
When this event occurs, the event history is stored into the internal memory. If the internal memory reaches the
maximum number of event history records it can store, all subsequent events are lost (Page 163 Loss of
event history information).
The event history, which have been stored in the internal memory during absence of the SD memory card, is
stored to the SD memory card. If the re-inserted SD memory card contains an event history file of the same file
size, the CPU module continues to store the event history information. If the file size is different, the CPU module
removes the existing event history file and creates a new event history file.
Size
20 bytes
12 bytes
40 to 1112bytes (variable)
*1