When to use parallel models?

Question

I am using TestStand to control test execution in a thermal chamber. I am unsure which process model best suits my needs (sequential, parallel, or batch). My requirements are as follows:
Up to 4 UUTs will be tested using a single test system. Each UUT shares assets in the test system. An entire sequence of tests will be run repetitively on each unit for a period of 24 hours. Within the 24 hour period, a single control signal is received from the thermal chamber indicating when tests should be run. (run for two hrs, soak for two hrs; run for two hrs, soak for two hrs �). Typically (prior to using TestStand) the test controller would run all tests on UUT#1, then all tests on UUT#2, then all tests on UUT#3, and so on. At the completion o
f this cycle, testing for UUT#1 would occur again. Each UUT has its own data report generated.
I know the parallel process model allows for the removal and/or addition of UUTs at any time during the test sequnce. Although that is a nice feature, it is not a necessity.
I would appreciate some advice on how to handle this situation. How can I affect the �infinite looping� of an entire test sequence for this multi-UUT environment?

Answer 1

Maz,
in the TestStandI course they stated that the serial model is for serial testing of one UUT after the other. The parallel model could somehow be assumed as multiple serial models running in parallel. The batch model is somehow inbetween or extra. It handles the test of a whole batch of UUTs in parallel, where there are some things to be tested in common.
Of course everything can be coded in every process model, but this would give up a lot of the built-in comfort.
In your case I would choose the parallel model, except there are some steps that need to be done on the whole batch at the same time. Consider some UUTs that must all pass a voltage test where you have just one DMM, and must be cooled down when all are done. This would be a batch model.
HTH and Greetin
gs from Germany!
LuI