Instruction Commands through VISA

[govindsankar]

Hi,

I have a TENMA DC Power supply unit connected using RS232. I have done two things. First I gave the command VSET1:24. This will set the voltage of channel 1 to 24V. This command works since I checked TENMA and I can see the voltage changing to 24V. Then I gave the command VSET? that should return current voltage setting which is 24V. Then I use VISA read to read this. But I am getting no output from VISA read. I also tried the IDN? function but nothing is coming from VISA read. Why is this? Kindly do help me. Thank You. 

[GerdW · Accepted solution]

Hi govindsankar,

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@govindsankar wrote:

Then I use VISA read to read this. But I am getting no output from VISA read. I also tried the IDN? function but nothing is coming from VISA read. Why is this?

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Most probable reason is the usage of BytesAtPort. Its usage is wrong in ~99.9% of all cases…

What's the point of typecasting strings into strings?

Why don't you attach your VI? We cannot debug images with LabVIEW!

Why do you use VISAClear (twice)?

What does the manual of your device tell you about message format and TermChars?