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Dicrete alert_hdl not available for float in 3.17

Posted: Fri Jul 16, 2021 2:53 pm
by DmSilkin
Hello!
Recently we have updated our projects to WINCCOA 3.17 P010.
We've noticed that after update it is impossible to set discrete and impulse alert handling type on float DPE's. There are only continious and multiinstance entrances.
Why is disrete type for float DPE's not available anymore?
Thanks in advance!

Re: Dicrete alert_hdl not available for float in 3.17

Posted: Mon Jul 19, 2021 1:03 pm
by leoknipp
In previous version it was a bug that you can use a discrete alert handling also for DP elements of type float.
This functionality has been deactivated as it may lead to performance issues in the Event Manager.

In software in general a float value has a limited precision. A value comparison of float values may not be accurate and therefore a value comparison shall not be made, e.g. also a old/new comparison of float values within a driver without using a _msg_conv to limit the number of digits after the comma does not make sense.

Best Regards
Leopold Knipp
Senior Support Specialist