Multiple Visa Ressource name

[nicos1712]

Hello,

I have a chemical system with several pH probes, connected via USB to my computer. I have already designed my program to display the pH, using VISA functions.

I would like to avoid repeating the program for each probe, so for each com port.

How can I write my program only once, so that it can be done for all COM ports?
Attached is my completed VI.

Thank you in advance.

[GerdW]

Hi nicos,

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@nicos1712 wrote:

How can I write my program only once, so that it can be done for all COM ports?

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Create a subVI and connect the VISA reference as input to the ConnPane…

Suggestions:

• Don't initialize the COM port with each iteration!
• Don't use BytesAtPort, there are most often better ways…
• Handle each device in its own loop - or use one loop to read all COM ports…

[RTSLVU]

On top of what GerdW said:

The first thing you need to do is watch this video: VIWeek 2020/Proper way to communicate over serial

Next let's think about your program architecture. One Big Loop is never a proper program architecture, I suggest a simple State Machine to start with.

Use a Cluster to hold your VISA sessions and open each Com port using a For Loop ONCE at the beginning of your program

Then later in your program you can read all the instruments sequentially using a For Loop

Don't forget to close your VISA sessions at the end of your program