weighted averages and Statistics other than time weighted

Discussion created by mikeloria on Jan 20, 2011
Latest reply on Jan 20, 2011 by mikeloria

We are producing a rolled product (coils) that is measured in feet, (usually 2000 to 4000 feet in length). In PI, I am creating a unitbatch for each coil and calculating the footage in 5 foot increments which I am plan to write these footage values into PI. The 5 foot increments are not equal time intervals since the line can stop, slowdown, speedup while the coil is being produced. There is process data such as temperatures, measured thickness, widths that I want to run statistics on such as avg,max, min, st dev.... I want to use the footage as the weighted component (1 process value for every 5 feet ) to calculate the statistics.


Is there a way(a function) to do this without having to determine what the process value is for each 5 foot increment which is what I am about to do?


I would be more than happy to execute this function programically and then store the result in PI. AF would be a wonderful place to have a formula for calculating the footage(which is based on a drive tach counter) and calculating the stats but I do not believe it can do that?


Also, is there a way in process book to use the footage in the x axis and then show the desired process variable(s) in the y scale?




This would be some seriously powerful capabilities if possible.




Thanks in advance for your help in this matter.