Hi,
On my project there is a requirement that for all DPEs with archive configs, there shall be at least one value sample logged in the Oracle database per hour, even if the value has not changed.
Is there a way to force writes to Oracle in this way?
We are using 3.16 with RDB archiving using redundant Oracle servers (forwarding)
Thanks
Force Write to Oracle
- leoknipp
- Posts:2928
- Joined: Tue Aug 24, 2010 7:28 pm
Re: Force Write to Oracle
WinCC OA saves data in the archives only if the value is set (event driven).
There is no possibility to write a value in the archive without setting it again.
What is the use case of writing the value again without changes?
If someone does a historical query to see which values have been set there will be a difference in the values really set and those written in the archives.
How to detect then those values which really were set by the driver/PLC?
Best Regards
Leopold Knipp
Senior Support Specialist
There is no possibility to write a value in the archive without setting it again.
What is the use case of writing the value again without changes?
If someone does a historical query to see which values have been set there will be a difference in the values really set and those written in the archives.
How to detect then those values which really were set by the driver/PLC?
Best Regards
Leopold Knipp
Senior Support Specialist
- jimtaylor
- Posts:32
- Joined: Tue Jun 11, 2013 10:18 am
Re: Force Write to Oracle
Thanks for the reply Leopold. I understand your point about not being able to detect PLC changed data.
I think the use case is that archives are deleted fairly regularly. e.g. imagine archives are deleted weekly, but a particular DPE last changed 2 weeks ago, then changed again today. If you run a report for yesterday you have no idea what value the DPE was at that time. The only record in the database would be today's change, because the previous change 2 weeks ago would be deleted.
I think the use case is that archives are deleted fairly regularly. e.g. imagine archives are deleted weekly, but a particular DPE last changed 2 weeks ago, then changed again today. If you run a report for yesterday you have no idea what value the DPE was at that time. The only record in the database would be today's change, because the previous change 2 weeks ago would be deleted.