Create Seq file via PLC and HMI

[emh00009]

Hello,

I have a PC running TestStand interfaced with a Beckhoff CP6607-0001-0020 PLC and HMI. The PLC controls a press that moves the PCB I want to test against a nailbed, as well as the test itself. The thing is that there are many PCB models, and for me it's a problem to constantly need to open TestStand and modify the test sequences. For that reason I'm interested in opening XML Seq files with the PLC and modifying them via the HMI (I would program a graphic interface to do this) so this way I could add steps or modify testing values. Is this possible? And if not, have you guys done anything similar than can help me for this specific application?

Thanks in advance

[~jiggawax~]

This is certainly possible.  I've built a recipe creator where the operator will select their steps and can change a few items for each step that we allow.  Then they can save the recipe and recall it based on serial number or other search criteria.

Underneath the hood we have some set steps in a template sequence file.  When the recipe runs it is just copying steps over to a sequence file it creates on the fly and injecting the values the user set.  Then it executes their recipe.

We are storing the recipes in JSON format but they could just as easily be XML or any other ASCII format.

The other advantage our architecture has is that we abstract the test algorithm away from the actual steps that do the pass/fail analysis.  This makes our code super reusable, especially in a situation like you have where it's high-mix but similar family.  In one case we used it on ultrasound probes and, like you said, there were just a few slight differences between the probes.  We were able to add new probes almost instantaneously to our test system, as long as they could reuse the current algorithms.

If you are interested in discussing more via email or phone feel free to PM me as this can get a little crazy.  Otherwise, you can ask specific questions here on the forums.

[pulidotech]

There was an NI Week presentation a couple years ago on TestStand with XML recipes.  I'm sure there have been others.

https://s3.amazonaws.com/v3-app_crowdc/assets/7/7b/7b1430895fcc48c2/1700Ochoco1033_0522_113930.origi...

There is some complexity with this kind of implementation, but if done well, adding and modifying recipes should be easier.  There are several people here (I'm one of them) available to help.

[~jiggawax~]

It should also be noted that sequence files can be saved in ASCII format (XML and INI if you have an older version). They are significantly larger.  I've seen a 20M file go to almost 600M.  Granted that was a very large sequence file and if you have sequence files that large you are TestStanding incorrectly.

Regards, 

[emh00009]

Hi jiggawax, thank you for your response

I'm really interested in recipe creation, as that's exactly what I'm supposed to do. I've been trying to manually modify the Sequence file to generate new steps, but I think I'm missing something, I get errors and it's hard to me to check it because I do not own the TestStand license, only my client does and I must be in his facilities to do so. So if you could share a little example of that implementation it would be really helpful

Thank you, best regards

[~jiggawax~]

I think it migh be too hard to share some of the example.  Plus some of it is our IP that we sell to our customers.  If you want to discuss offline maybe we could show you some stuff.

I can give you a basic overview of what we are doing.

All of our tests are sequence calls to subsequences.  So we'll use a sequence call set to multi-numeric limit test or numeric limit test, etc...  Then we have a sequence file with a sequence that shows all of the calls we can possibly make that they would want to configure as part of their recipe.  At this point I think there are about 40 or 50.  We put all of the "configurable" items in the step attributes.  Then we have a GUI that goes through this sequence file and displays all of the steps and configurable parts.  They select what they want and can re-order and configure how they like in the GUI.  They can even call the same step multiple times in a row with different parameters.  Then we save all of the info off to a JSON file.

During execution they select a recipe and we read in the JSON file and copy all of the steps they've configured, and in the order they've configured, to our execution copy and then run each step. 

It actually works really nicely.  It is a great solution for high-mix with slight variations.  And to be honest it works great for design verification as well because then engineers can configure on the fly.

Regards,