Create an offset

[softserve]

I am evaluating TestStand and I have a test that measures capacitance in an IC. I would like to run the test with no UUT to collect the stray capacitance in my test system and use that as an offset for further tests.  I only need to run this step once at the beginning of testing. How does make one step run only once, while subsequent steps can be executed multiple times. And how do I use the data as an offset.  Thank you.

[Dennis_Knutson · Accepted solution]

You could add a SequenceFileLoad callback so that the cal step is only run when the sequence file is loaded. Save the result to a station global. Whenever you do a test, make the step result equal to the measurement minus the variable. There are other ways to do a test only once such as a precondition where it depends on a variable that you would update after running the test.