Mini-Circuits LabVIEW HTTP client doesn't work but browser/CURL does

[jhoover]

I wish that I had found this post sooner! I have spent at least 10 hours looking into this issue (Claude had me looking into a lot of empty rabbit holes). I too am trying to communicate with a Mini-Circuits ZTM RF switch. A former co-worker wrote the driver for this instrument and it has been used for at least 6 years on 20+ PC's across multiple labview versions beginning with 2017 and now 2026 without issue. Before finding this post I too was able get those commands to work using the double ??.

This post is good confirmation that its not just my setup. I don't see a way to downgrade just NI-Curl so I guess i will need to update this driver to comply. Fortunately the double ?? also works with the older labview versions.

[avogadro5]

I reported this to mini-circuits so they could update their example VI but they have not taken it upon themselves to do so.

[thomas-allibe]

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@avogadro5 wrote:

Been at this a long time, some more info that might mean something to someone who understands HTTP:

• The vendor provides example code for both LabVIEW and python
• Both examples append a ':' after the / so 'http://192.168.1.60/:FIRMWARE?'
• Only the python example works
• Omitting the ':' in the python example does not affect the result so I think it's a red herring
• The python example uses "urllib" module when I tried python myself I used "requests" and got the same (bad) response as my LabVIEW attempt
• The LabVIEW example doesn't work and has the same issue as the one I wrote from scratch because it's doing the same thing
  
• The NI advanced HTTP toolkit and JKI toolkit both have the same issue as the built-in library

The fact the LabVIEW example doesn't work means it may be something to ask the vendor about...

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Are you sure it's not a semi-colon ";" instead of a colon ":"? In the reference manual you linked, page 9:

If it has one, you need to provide a password before the ";". If it doesn't, I guess both "COMMAND" and ";COMMAND" are valid.
But it seems the device is very forgiving if it also accepts ":". There's also the possibility that the doc is not up to date.

Also have you tried encoding the "?" character into "%3F" (and maybe ":" into "%3A" or ";" into "%3B" to be consistent)?

Something like "http://10.10.10.10/FIRMWARE%3F"

It should prevent sanitization from LabVIEW HTTP client, but the device may not support it...

HTML URL Encoding Reference

[jhoover]

To be fair to Mini-Circuits I believe that this issue is caused by a LabView/ NI-Curl change/update. These commands have worked for us for years. We have used them in LabView 2017, 2019, 2023 64bit without any issues. The issue started when we transitioned to LabView 2026 64bit. The only commands that do not work are the commands that end with a "?". The LabView 2026 64bit HTTP client completely strips the ? from the command before sending it to the instrument.

I also tested these commands via a web browser, and the GUI provided by Mini-Circuits.

While troubleshooting with Claude I did try "%3A", "%3B", and "%3F". They did not work.