Issues with compression

Discussion created by andrew_Inwood on Jan 14, 2014
Latest reply on Jan 15, 2014 by RJKSolutions

We have a flow meter tag, that is ranged 0 to 10 sm³/s.  Currently, the PI data stored has a resolution of on ±0.1 sm³/s (i.e. it tells me that the current flow is 1.6 sm³/s, and I won't get an update until it hits 1.5 sm³/s).  I wanted to increase the resolution on it.


So:  I modified the tag attributes.  CompDevPercent was set to 0.01, but the span was set to 100 ("zero" is 0 by the way). So I changed the span to 10.  This changed the compdev to 0.001.  Excdev is at 0.005.


However, this hasn't improved things.  I still don't get any better data resolution than ±0.1 sm³/s. 


Any suggestions?  I was wondering whether the DCS (a Bailey) is filtering the data before it gets to the PI Buffer server.