Communication issue

[Selva@2004]

Hi,

I have two serial devices:

1. Load cell controller

2. Temperature controller (3 channels)

Both communicate through a COM (RS-232) port.

On my old PC (Windows 10, LabVIEW 2014 Chinese), both devices work correctly.

On my new PC (Windows 11, LabVIEW 2014 English), neither device responds. I send the command, but "Bytes at Port" stays 0.

I am using the same VI, same cable, and the same serial settings.

Has anyone faced this issue? Is it related to Windows 11, NI-VISA, or COM port drivers?

Thanks.

[santo_13]

Did you select the correct VISA resource name?

[crossrulz]

---

Selva@2004 wrote:

On my new PC (Windows 11, LabVIEW 2014 English), neither device responds. I send the command, but "Bytes at Port" stays 0.

---

And how exactly are you using Bytes At Port?

Without seeing the code, my guess is that your new computer is a lot faster than your older one and therefore you are checking for the bytes at the port quicker than you were before. Using proper serial communications (see this presentation: VIWeek 2020/Proper way to communicate over serial) can alleviate that problem.

If you want more detailed suggestions, you will need to supply some code and details on the instruments you are trying to talk to.

[Selva@2004]

I have attached the NI IO trace image. 

Now I am able to read temperature control values, but I can't read load cell values consistently. Sometimes I am able to read load cell values, and sometimes I can' t.

[Bob_Schor]

Here are some suggestions:

• Watch Crossrulz' Video, and follow his suggesting on how to do Serial Communication!
• Show us the LabVIEW code, particularly the code involving Serial Communication (done through VISA).
  • Best is to send us a VI (or sub-VI), preferably in a LabVIEW version a few years older than current, such as LabVIEW 2021).
  • An alternative (might not be available in LabVIEW 2014) is to create a LabVIEW "Snippet", a .png file that which dropped into a blank Block Diagram, "expands" automagically into executable LabVIEW code.
• Have you tried writing a small Test VI that just tried to "wake up" your device and initialize the VISA system, saving the "acknowledgement" string?  What happens when you do this?  [Feel free to send us this Test VI].
• Have you tried opening MAX and seeing if you can open a VISA channel to your device and see if you can establish communication?  Try sending an initialization string, then see what the device sends back to you.

Bob Schor