SIMATIC WinCC Open Architecture Forum

In the ETM document
Basic and Operating Conditions for the Use of WinCC OA together with Safety Related Systems up to SIL 3,
section 4.8 Requirements for the Peripheral Connection there's the following statement.

"In case of a redundancy switch the validity of the process image must be ensured by a general query after the redundancy switch."

I can't see how this is or has to be implemented.
Does a general query occur automatically on a redundancy switch? If not how is it configured/implemented ?
Does it depend on the driver thats used for comms with the PLC, I'm using S7Plus?

Many thanks

In standard configuration the WinCC OA drivers do a general query during a redundancy switch.
With the config entry autoGQ you can define when the drivers shall do a general query. For details please have a look at the WinCC OA Documentation.

Best Regards
Leopold Knipp
Senior Support Specialist