hi, You all got me going with this script for an average of a three hour block of time:
how difficult would it be to get that to loop through the previous three days? So I can get the average of the previous three days between 0300 and 0600.
I made three of these scripts, one for each of the days, and then averaged those results but maybe I can do it in once shot?
I know there is a looping function but it’s beyond me. I wish I could learn to script but I just can’t seem to speak that language…
The way I understand this, is you are looking for the average of the average for each of the last three days during a 3 hour block on each day. Is that correct?
that was how I hacked it together. I’m not sure mathematically, out of the bounds of my knowledge, if there would be a difference in an average of three averages or the average of all the values from that the 3day/3hour timer period. either way would work for me I think
Ok, a quick internet search says that the average of the averages and the average of all the raw datapoints will be the same if the sample sizes are all the same. In my case they should be so either way would work
Thanks! I think it’s close, but I get different results from my other averages. If I switch the command to system.tag.queryTagHistory should the For process still work? I only get 1 days worth of data when I do that.
You are manually querying a database. Does that mean you do not have tag historian?
You could start by editing the function to take a date parameter as an input (default none uses system.date.now() ) and use that date as your “now” in the script. Then just call the same function 3 times for the last 3 days and compute the average in the script.
def averageWindow(dateStart = none, span = 3)
if dateStart is none:
now = system.date.now()
else:
now = dateStart
previousDay = system.date.addDays(now, -1)
time_3am_previous_day = system.date.setTime(previousDay, span, 0, 0)
startDate = time_3am_previous_day
endDate = system.date.addHours(startDate, 3)
data = system.tag.queryTagCalculations(
paths=['[default]ST25/_25_FI_110X_Total'],
calculations=['Average'],
startDate=startDate,
endDate=endDate
return data.getValueAt(0,1)
#range could be 0-2 depending on when this runs
avgs = [ averageWindow(system.date.addDays(system.date.now(), -1*day)) for day in range(1,3) ]
avg = sum(avgs)/len(avgs)
Can also pass the path in and make this script much more useful
I do have the tags in historian; I think I went this way because I didn’t understand what I was doing. How does having a tag history change the approach?
Use custom properties to hold the “selected” dates and use expressions to determine start and end. Bind the custom props to the date inputs in the tag history binding:
Please update the title. The process will be much the same.
Create 4 custom properties on the view (start, end, data, avg).
start:
dateArithmetic(now(),-3,"day")
end:
now()
data:
tag history binding for your tag using the start and end date specified
avg (pseudocode):
mean({data},1)
You may want to change the argument for now() if you don’t want it updating so often. Or use a script when the view opens to set start and end instead of using a binding. If you’re swapping between hours/days you’ll need some sort of additional logic. If you’re displaying both you can duplicate the process for the other range(s).
Add 3 (we can use a transform since this is perspective so that removes a step, no need for the “data” value) custom values in the custom props section on the right.
