VISA: (Hex 0xBFFF0072) The resource is valid, but VISA cannot currently access it.

[DMC5110]

Hello macncheese,

I really appreciate your reply - sorry for my super-delayed response! I've been busy these past few months finishing up my thesis and defending it.

I did try to reinstall the drivers, but it seemed that they were all up-to-date, so reinstalling didn't change anything. Ultimately I think it was a hardware issue: I think water had spilled out of a container on the balance at some point and gotten into the pinned connector cable that linked the balance to the computer. When I disconnected the cable, the terminals looked corroded beyond recovery. 😕 Oh well.

Thanks anyways for trying to help!

[alpha10]

Help please !!

[crossrulz]

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@alpha10 wrote:

Help please !!

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That error typically means you are using the serial port in another application.  A serial port can only be used by 1 process at a time.

[ragavposti]

Hi all,

I am also facing the same issue while interfacing a power supply unit connected by USB-RS 232 connector to my PC.

So instead of making a Labview program I first checked the basic I/O option of the VISA Test panel and enter a command to communicate with the instrument. (*IDN?)

So the write option is showing no error but when I am checking for query or read option I am getting the following error (screenshot attached).

Is this error is because of the reason that I may be using the serial port in another application? if yes, then how to check it and resolve it?

P.S. I am using a third-party RS232 connector and already installed the latest drivers for it.

[pincpanter]

No it's not the same issue nor the same error. The port opening is ok but there is an actual input error.

Are you sure that the port settings match those of the instrument? Does the unit outputs data continuously? Does the unit react to an IDN request?

[ragavposti]

Sorry, I posted this problem in a rush, so I didn't check the subject properly.

My instrument is currently showing only the Baud rate, which I matched with the port settings. And in the above-sent screenshot, I tried the same command (IDN), but somehow it is not able to read it, although, in writing, there is no issue.

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Raghav

[rolfk]

What device is it? A device has to support specifically any command you try to send it too. If it doesn't recognize the command most devices will simply show you a nose and stay silent.

Only devices that support at least a subset of the GPIB 488.2 standard will support the IDN? command. And only measurement instruments of more or less T&M type manufacturers like Keithley, Agilent/Keysight, Tektronix and similar will do that usually.

Many others will cook up their own idea of a protocol.

[ragavposti]

I am using a Keithley 2231A-30-3 Triple Channel Power supply, and I checked it's manual as well, and IDN is a valid command in my case.

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Raghav

[rolfk]

error 0xBFFF003E is a generic IO error. This means that VISA tried to call some Windows API function which returned an unexpected error. That can happen for USB-RS232 adapters who use a buggy driver. You might have to install a specific Windows USB driver for your device. The standard Windows USB-COMM driver seems to trip over something that the USB controller in your device is doing.

[pincpanter]

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@ragavposti  ha scritto:

I am using a Keithley 2231A-30-3 Triple Channel Power supply, and I checked it's manual as well, and IDN is a valid command in my case.

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Raghav

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The unit Reference Manual says the serial interface is TTL and not RS-232.

A standard RS-232 USB adapter would not work.