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How to pass variables defined in LabVIEW to teststand sequence via teststand operator interface?

Hello all,


I am working on a project & I am very new to LabVIEW & Teststand both. This project consists of a main GUI, a teststand operator interface & a test sequence.


How the project works?

Part 1 - Main GUI (Refer screenshot 115 & 116)

  • This is the 1st GUI window the operator will see. It loads 8 string input parameters from respective locations. then read the string data inside it. Once this 8 inputs are loaded. Operator will click on "Run Build Transparency sequence" button.

Part 2 - Upgraded Teststand operator interface (Refer screenshot - 117 & 118)

  • Once the "Run Build Transparency Sequence" button is pressed. The operator should be able to see 'Teststand operator Interface' window. Where, One sequence is by default loaded. Now, the 8 inputs loaded in Part - 1 should be passed to the default sequence and sequence should start running & operator should be able to see the test report.

Part 3 - Sub VI inside 'Teststand operator Interface' (Screenshots 95 & 97)

  • I have manually added this vi in teststand operator interface block diagram, so that I can send the 8 string inputs in main GUI to teststand sequence.
  • I have tried developing 2 different sub VI's. one using Application manager control & other using sequence context control. These both Vi's throw different errors and I couldn't run the test sequence.
  • For the sub VI which used sequence context as control, I called this vi in a step of teststand sequence. but it still didn't work.

Project status - 

  • Part-1 works well. 8 Inputs get loaded successfully. Then Teststand operator interface window also opens successfully. 
  • Error occurs when LabVIEW tries to run sub VI I designed.

My queries -

  1. Can you please tell which method in sub VI (Application manager or sequence context control) is a correct approach to run my project successfully? or else, if both these are incorrect then which method should I follow?
  2. Let me know, if you need me to explain my questions more clearly. I have attached all the necessary screenshots. please check them & help me with your suggestions so that I can make this project running.

VI's and its names in my project

  1. Main GUI - (VI name:
  2. My upgraded Teststand Operator Interface - (VI name: Teststand operator Interface -
  3. Sub VI inside Teststand operator Interface - (VI name: Sequence Context -


Thanks & Regards,


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Message 1 of 4

You need to use UI Messages to pass information to and from your sequence file to the UI:


If you need to get it from the UI to the sequence file you post a UI message from the sequence file with the sequence context.  Then you can set variables from there back to the sequence file.


Hope this helps,

~Will work for kudos and/or BBQ~
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Message 2 of 4

Also,  I will be presenting at the GLA Summit on building User Interfaces in LabVIEW for TestStand.  I will demonstrate UI Messages.

~Will work for kudos and/or BBQ~
Message 3 of 4

It is also possible to use synchronization objects. See this

If we want to have LabVIEW-based synchronization then we could use TCP (AMC?) or in some cases simple LabVIEW queues.

But as it was mentioned, NI recommends UI Messages in this case.

Michał Bieńkowski

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Message 4 of 4