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5.6 Online Program Change for Redundancy
5.6.1 Writing to the CPU Module in STOP Status
5
(3) Precautions
(a) If programs cannot be written to the standby system CPU module
In the following cases, the data will be written into only the CPU module to which
GX Developer is connected:
• Either or both powers on control system/standby system are OFF
• Either or both CPU modules on control system/standby system are in RESET
• Either or both systems have a hardware failure
• Either or both CPU modules on control system/standby system have
"Watchdog timer error (error code: 5000 or 5001)"
• Tracking cable disconnection or malfunction
In these cases, the error dialog box in Diagram 5.60 will appear on GX Developer.
(b) Operations prohibited during online program change
Do not perform the following operations in either control system or standby
system during online program change:
• System power OFF
• CPU module reset
• Tracking cable connection or disconnection
If any of the above operations is performed, "Consistency check between system
A and B" may cause the "FILE DIFF. (error code: 6000) stop error in the standby
system CPU module.
In addition, the error dialog box in Diagram 5.61 will also appear on the GX
Developer that performed the PC write.
If the error dialog box Diagram 5.61 appears on GX Developer, remove the
condition indicated by the error dialog box and redo the PLC write.
(c) Writing a program via module mounted to extension base unit
Writing a program via a module mounted to the extension base unit is disabled.
For details, refer to the following manuals.
GX Developer Version 8 Operating Manual
PX Developer Version 1 Operating Manual (Programming Tool)
Diagram 5.60 Error Dialog Box Displayed on GX Developer
Diagram 5.61 Error Dialog Box Displayed on GX Developer