Peter Falk

Filtering product specific data from tag with time delay

Discussion created by Peter Falk on Mar 26, 2014



I was wondering if someone could help find a good solution to my problem.  Thank you for any help you can offer.



I have a tag for which the instrument records data for multiple products on the same PI tag.  I need to be able to graph and run statics (min, max, standard dev, control charts, etc) in excel on the data for each product separately so a Datalink solution is needed.  I would also like to create a Processbook display to trend each product separately if possible. 


The system functions as follows:

The instrument analyses the material for product A for a period of time then the sample valve closes.  Next a different sample valve opens and the instrument analyses the material for product B for a period of time.  This cycle repeats itself 24/7.  The cycle length can vary.

The sample valve positions are tags in the PI system. 

The dynamics of the sampling system are such that there is a 10 minute time delay between when sample valve opens and when the system starts to output data related to the associated sample valve.  The system is running a purge during this time frame.


To sum up my question, how do I filter the data to generate a report on Product A and B separately when their data is stored on the same PI tag.  I need a filter that will start collecting the data 10 minutes after the associated sample valve opens and stops when the sample valve closes.


Here is an example of the trends.

TOC trend.JPG