hi All
As we all know bad data can sabotage OEE readings.
My current understanding is that this issue can be solved if i use tag event on the PLC tag which transfer the data to its "twin" memory tag only if the quality of the data is good.
This sounds robust to me - do you use it like this in your projects?
If there is existing bad data in the history is it possible to remove it using database management studio or can is sabotage Ignition history logging?
3 Is there a way to transfer history data from one tag to the other memory tag with different name in special situations?
Meh. I generally do not use Ignition's historian for OEE-related source data. I use transaction groups (or scripted equivalent) to regularly store odometer-style production counters (raw production, good production, etc.) and transfer events from PLC buffers (where the PLC places event code and timestamp in a ring buffer).
Some things are not well-matched to the historian.
I am really glad to be back on the forum again and thanks for reply!
I use transaction groups (or scripted equivalent) to regularly store odometer-style production counters (raw production, good production, etc.) and transfer events from PLC buffers (where the PLC places event code and timestamp in a ring buffer).
Transaction groups give a lot more flexibility for the data capture but would you not prevent bad data from being stored?
You can use an always-execute expression as your trigger, and include quality checks in that expression.
Or script the database insert, with whatever logic makes most sense for your environment. (I tend to script this stuff anyways, as TGs have poor handshaking options.)
Or, you can use the 'Store quality code' setting to get an aggregate quality of all the tags. Sometimes, it's useful to know if the quality of a tag goes bad.
