GE GFK-0787B user manual Online Changes

4

output states of the blocks, the block does not use those outputs in its output voting. The block(s) continue to ignore outputs from the PLC until they match those of the block's voted outputs or until commanded to do so by setting the FORCLOG command bit (%M12263). This is covered on more detail on page 7-17.

Startup requires multiple PLC sweeps to complete. Execution of the application program should not be started until initialization and synchronization have been completed successfully.

Online Changes

The GMR configuration can be set up to either permit or reject online program changes. These changes result in checksum mismatches. Such mismatches are handled as described below by the PLCs in the system.

Typeof Mismatch	Configured to Allow Changes		Configured to RejectChanges
orChange
Detected	Changed/StartedPLC	Other PLC(s)	Changed/StartedPLC	OtherPLC(s)
Program Checksum	ªProgramMismatchº	ªProgramMismatchº	ªProgram Mismatchº mes-	No Action
mismatch at startup	message logged	message logged	sage logged. PLC stopped
( Following PLC Fault	ªProgramMismatchº	ªProgramMismatchº	N/A ± PLC is stopped	No Action
Reset)	messagere-logged	messagere-logged
Program Checksum	ªProgram Changeº mes-	ªProgram Changedº mes-	ªProgram Changedº mes-	No Action
change while running	sage logged	sage logged	sage logged
			PLC stopped
( Following PLC Fault	ªProgramMismatchº	ªProgramMismatchº	N/A ± PLC is stopped	No Action
Reset)	message logged	message logged
GMRConfiguration	ªGMR Configuration	No Action	ªGMR Configuration	No Action
Checksummismatch	Mismatchº and ªPro-		Mismatchº and ªProgram
at startup	gram Mismatchº mes-		Mismatchºmessages
	sages logged. PLC		logged. PLC stopped
	stopped
( Following PLC Fault	N/A ± PLC is stopped.	No Action	N/A ± PLC is stopped	No Action
Reset)
ConfigurationCheck-	ªGMR Configuration	ªGMR Configuration	ªGMR Configuration	No Action
sum mismatch while	Changedº and ªProgram	Changedº and ªProgram	Changeº and ªProgram
running	Changedº messages	Changedº messages	Changedº messages
	logged.	logged.	logged. PLC stopped
( Following PLC Fault	ªGMR Configuration	ªGMR Configuration	N/A ± PLC is stopped	No Action
Reset)	Mismatchºmessage	Mismatchºmessage
	logged.	logged

In all cases, a fault message is logged into the PLC Fault Table.

If the fault condition remains after the PLC Fault is reset, the message is relogged. The message indicates which PLC has changed, or which mismatches.

A change to the GMR Configuration information takes effect only when the PLC is transitioned from Stop to Run mode. Therefore, the PLC should be placed in Stop mode before downloading a new GMR Configuration.

Autotesting is suspended if a PLC is started up with a new configuration. After all PLCs have been given the same configuration, autotesting will resume.

GFK-0787B Chapter 4 PLC Subsystem 4-3