Scott,
In Test UUTs execution entry point of the sequential model there is Locals.ContinueTesting. This is updated through the sequence call of PreUUT Callback. In the PreUUT, Parameters.ContinueTesting is set, and because it is call by reference it sets Test UUTs >> Locals.ContinueTesting. And then Test UUTs >> Locals.ContinueTesting is checked by the next step, Goto End of UUT Loop If No More UUTs. So you need to set either Test UUTs >> Locals.ContinueTesting, or PreUUT>>Parameters.ContinueTesting sometime before Goto End of UUT Loop If No More UUTs step.
Are you using the TestStand Sequence Editor or an Operator Interface? When you say, "go into our user interface" do you mean launch your own PreUUT dialog that gets the serial number, or something else? Usually what I've seen is people want to replace the PreUUT dialog with a serial number control, and the Stop Execution button on the front panel of their Operator interface (OI). In this case your PreUUT will need to send some UI Msg to the OI to say, "I'm at PreUUT now, highlight the serial number control and Stop button. The PreUUT should then wait for a valid serial number or Stop button input before it sets Parameters.ContinueTesting and moves on. The simplest way to do that is poll a Station Global or some other variable(s) and have your OI write to that variable when the operator enters the info. There are many other good ways to do this too.
A key design guideline to keep in mind is, if you design your sequences to run the same in the Sequence Editor and your Operator interface then it's easier to develop and debug. Another way to say this is, if you can help it, don't couple your test sequences to an OI. Imho the pop ups are less work and less custom code, but its a common request and not really difficult to move the popup functionality into the OI.
Hope at least part of this is what you're after.
cc
