We have the following setup - Plant SCADA Trend tag - push it through Wonderware Historian Connector to AVEVA Historian - replicate to PI.
For the Trend tag in Plant SCADA, we have a Min value of -3.4e+38 and max value of 3.4e+38.
When the analog tag was historized and replicated, there was an error produced and the Historian went into StoreForward mode. The Historian had to be rebooted to get it back to running.
When the Analog tag was not Historized and replicated we did not get the error message and the replication to PI worked fine.
We came to this conclusion because when we removed the analog tags from historizing in Plant Scada, the Historian replicated properly. We also were able to replicate Historian System Tags and digital Plant Scada tags.
There was a message from OSI PI that the range for the mentioned values exceeded limits. It has been confirmed that OSI PI accepts a range of Float32 (32 bits) as its span.
The issue is the Span which is the difference between the maximum and minimum. In this case the Span that it is trying to write to the PI Point is 6.8e+38 which is outside the range of a Float32 and so it cannot be accepted.
We tried to change the range for the tag, recompiled and restarted the connector that the trend tag was based on but this did not work. When we changed the min max values of the variable tag in Plant Scada it did not change in the Historian.
As a workaround, we converted the 8-byte Trend tag in Plant SCADA to a 2-byte tag and the above symptoms did not occur.
However, this caused an issue with the precision of the value as the resolution is reduced. So the real values lost their precision.
So, I would like to know if the Historian or the connector is able to accommodate the span difference to ensure replication to PI.
Thanks.
