Calculation Problem.

Discussion created by scottl330 on Mar 15, 2013
Latest reply on Mar 21, 2013 by Gopal

I have a calculation that I have been asked to provide using PI data that I am struggling with and was hopeful that someone out there has done something like this in the past and can provide guidance.

The situation is that we have 67 ovens per battery; each oven has a thermocouple with a scan rate of 1 minute.  There are three TC's per oven, so we need 3 seperate calculations for each TC.  We want to be able to take a moving 72 hour average for the entire 67 ovens.  One major issue is that the TC’s commonly report band values, negative values, EquipFail, or 0 for example.

My challenge is to have a formula that will exclude any value outside a certain range, take the average of each oven individually, then take the average of the 67 ovens. There are 4 batteries total, so performance is a consideration for this project.

I was looking at using a performance equation with the TagAve function for each oven and then use the AVE function, but am struggling with a good way to remove the bad values. I am also concerned that using a PE with 67 ovens per battery and three tags per oven might cause performance issue.

Any ideas?