Citect / Historian Backfilling Strings

[Martin Cole 0]

Hi All I've recently been tasked with the implementation and installation of a Historian system into a plant, and I’ve encountered a major issue, which I hope someone can help me with. Due to the network architecture the SCADA will occasionally be operating while disconnected from the Historian server, which isn't an issue due to the I/O data being backfilled from trend files, once connectivity is restored... However, there are a large amount of Strings which need to be stored historically too, due to citect inability to trend strings I’m wondering if anyone has found a sensible work around for this? I hope someone can help Kind Regards Martin Cole

[tragically1969 0]

Hmm, interesting one, i dont think you will be able to get a workaround for the backfilling, why does the SCADA have to be disconnected from the Historian server ? Only thing i can maybe thing of doing is writing the strings on change to a temporary DB which sits on the Citect machine then is read and uploaded on schedule to the Historian DB, might be a bit messy and require a bit of thinkng about but should work ? Have you spolen to Citect support, they are pretty good and may give some pointers.

[Martin Cole 0]

Hi Under normal operation the machine will be connected to the Historian, however there will be moments when it won't which is why we have to prove to the customer that the system can backfill successfully to fulfil this possible scenario. I’ve spoken to citect and the approach they recommend is that the strings are written to CSV device and then use a SQL task to retrieve the CSV and parse the data back into the string sample table. I’ve discovered this to be troublesome and not very bullet proof, I was hoping someone might have a better work around. I personally like the sound of the local DB on the SCADA and then just sync the data, however again the customer isn’t keen, because it doesn’t fall into there recommended specification. Thanks for your help though… Regards

[tragically1969 0]

Sounds like Citect are thinking similar to me, to be honest if they have no answer then its going to be unlikely that anybody else has got a workaround. Sounds like the customer is asking the software to do somethig thats outside its scope, i know that does not help you ! Cheers