PI & Limits

Discussion created by wpurrer on Jan 11, 2013
Latest reply on Jan 16, 2013 by rdavin

Hi everyone,


has anyone expierience with limits and Osisoft PI (AF,EF,...)


Usually someone has for the values we all record in PI some kind of limits.
- this limits maybe change depending on the productiontype,...
- for one value we typicall a setpoint, high limit, high high,....
- this limits also can change (not very often - but still)


- limits are not only a PCS / DCS Task but also for more process information as a whole...


What options are there to combine this with Osisoft PI and it's tools.


When you store this limit's in tags you run in a couple of problems
- when you have for example 100 Tags * 5 (for setpoint,high,...) * 3  Production lines * 3 Production Types = 4500 Tags,
- what you maybe typically do is that you have one tag (which holds the active value - with a performance equation behind which points depending on the production type to the right "base limit".


Storing it in AF
- how do you architecture the whole thing
- do have you value as an attribute (and the setpoint, limits,... as a child attribute)
- do you use one element per value and just the limits are further attributes (with this you can create attribute template and maybe reuse limit calculations)
- but with this the whole "template concept (template site, template area,....) doesn't really work)


Storing it in Event Frames
- one eventframe is one recipe,...


How you visualize the limits best ?
- when you wan't to display the value and the limit's in processbook you have the option to display it in SQC (which then is a pain in the ass to really analyze data) or use a "common" trend (where it also is a pain to get the colors right (setpoint green, limits red,...  and you have a lot of useless information because of the description below and the values on the right.



- coresight the same


- datalink the same.


Integration with notification?
- this is maybe the easiest,... if you have solved the other ones,..


Some inputs
- Best Practice,...
- a PI System which supports limits by hearts would be nice