What I have is a program that tests one unit and I need it to test four of the same units, the same way at the same time. I have attached a schematic also if that helps. Thanks again for the help.
You should be able to generate all the input signals once and input them in parallel to all four DUT's. The outputs (clutch coil drive signals) will need to be monitored separately for the individual unit's reaction to the inputs. The overcurrent status is an input as well, and would need to be simulated individually, but it's the current in the output line, which already needs to be separate.
So you need to create some kind of sequence that simulates all the variations in the input lines. Then parallel code or a subroutine called four times with different addresses to monitor the DUT's reaction to the stimulus. You could do it with stage but I'm not a big fan of stage. I'd use a drum (DRUM, EDRUM, etc.) or some timers and other logic.
You might want to consider adding an automatic acceptor/rejector rather than pass/fail indicators, to eliminate the possibility that the operator will get tired and sort the outgoing parts incorrectly. Plus maybe an MMI to show the totals count and percentages accepted and rejected and the distribution of rejection causes. This can help in diagnosing the cause of a rash of failures and aid in process improvement and the tracking of it.
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