How to force testsockets to enter preUUT one by one and not at the same time in parallel model

[Skoda3]

I have 4 testscokets and I use parallel process model.

In preUUT sequence I :

 - first check how many parts were already tested

- and then if number of already tested parts is less than number of parts to be tested, I wait PLC to send me signal "new part ready".

-after that I add +1 to numer of parts already tested (count parts tested++)

The problem comes in situations when 2 or more testsockets enter preUUT at the same time and before PLC sends signal to first of the sockets and before I count +1 to parts already tested, the other sockets already wait for PLC signal.

I want to create some kind of "Lock" so that testsockets enter preUUT one by one. This will solve problem because there is a "wait" loop insice od preUUT in each of the sockets. 

How this can be realyzed in TS?

[Norbert_B]

Implement a module which provides the PLC communication and handles the synchronization of the sockets.

[Skoda3]

What do you mean by module? 

I have communication between PLC and Labview implemented (Modbus)

[Norbert_B]

This makes it simpler: LV VIs are by default blocking. That means if each socket calls the same standard ("non-reentrant") VI, that VI blocks all sockets except the one it runs for currently.

As a result, you can implement the VI as such that it knows which socket calls it (RunState.TestSockets.MyIndex) and behave accordingly.

Is that already enough for your needs?