Sqltag history with value timestamp


With 7.5.0 (and beta5 7.5.1), it is no more possible to use the value time stamp with sqltag history.
As soon as you select this option, a new scanclass is created “exempt” is created in sqlth_scinfo and associated with the tag in the sqlth_te :scratch:


I believe it was that way for 7.4 as well. But why do you say it doesn’t work? The Exempt scan class means that due to the settings of the tag or scan class, the system can’t use the normal scan class execution validation for determining when the tag was valid or not. That is, normally when the system looks at a given time for data, it also looks at whether the scan class was running at the time, to know whether it’s ok to interpolate the value. When using the value timestamp, the time provided may be from long ago, and so it doesn’t make sense to also consult the scan class record. Therefore, we have an “exempt” scan class that they get put under to avoid this.

Now, is the value not being stored? Is the timestamp of the value not correct?