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5.6 Online Program Change for Redundancy
5.6.2 Program Change While CPU is Running
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(d) Processing when the target programs are different between the control
system and standby system CPU modules
If the target programs are different between the control system and standby
system CPU modules, it will be written to the control system CPU module only.
If this happens, the error dialog box in Diagram 5.71 will appear on GX Developer:
(e) Access to programs being changed online
The programs being changed online cannot be accessed by GX Developer.
If programs in RUN write by GX Developer are accessed, the error dialog box in
Diagram 5.72 will appear on GX Developer:
Access the programs again after the online program change is complete.
(f) When online program change cannot be executed to either control system
or standby system
In the following cases, online program change cannot be executed to either
control system or standby system:
1) Online program change when a fault has occurred in the standby system
The error dialog box illustrated below will appear if online program change is
executed during the following:
• Standby system power is OFF
• Standby system CPU is resetting
• WDT error occurring on the standby system CPU
• Tracking cable not connected or malfunctioning
2) Changing programs being accessed by the other GX Developer online
The error dialog box Diagram 5.74 will appear if online program change is
executed to programs being accessed by the other GX Developer:
Diagram 5.71 Error Dialog Box Displayed on GX Developer
Diagram 5.72 Error Dialog Box Displayed on GX Developer
Diagram 5.73 Error Dialog Box Displayed on GX Developer
Diagram 5.74 Error Dialog Box Displayed on GX Developer