5
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5.6 Online Program Change for Redundancy
5.6.2 Program Change While CPU is Running
5
(7) Precautions
(a) When program memory space is insufficient for writing files in RUN
To write files to the program memory in RUN, a working memory area (free area)
as large as the size of the files is required.
If a sufficient working memory area is not reserved in the program memory, writing
files in RUN is not executable.
However, if the necessary space is available in a memory card (SRAM card or
ATA card), a batch of files can be written into the card during RUN.
(b) Memory used for writing files in RUN
When writing files in RUN, the same kind of memory is used for the control and
standby system CPU modules.
If different memories are reserved for them, writing files in RUN is not executed.
When writing files in RUN fails the error dialog box in Diagram 5.70 appears.
(c) Operations disabled during online program change
Do not perform the following operation during online program change:
• System power OFF
• CPU module reset
• Tracking cable connection or disconnection
Executing any of the above operations may corrupt the contents of program
memory.
Table5.57 Memories for Control System and Standby System CPU Modules and Executability of Writing
Files in RUN
Memory available for control
system
Memory available for standby system
Program memory
Memory card
Program memory
Memory card
Diagram 5.70 Error Dialog Box Displayed on GX Developer