Labview Initialize problem with Keithley 6485

[cghw]

Hello,

   I am using Labview 2024 with Windows 11. I seem to have problems initialising and acquiring data from a Keithley 6485 picoammeter. Previously, I have got a program using the Keithley 6485 working using Labview 2018 on a different PC.

I get this error message when running under LV 2024:

Error -1073807360 occurred at VISA Open in Keithley 648X Series.lvlib:Initialize.vi->KeithleyTest_v1.vi
Possible reason(s):

VISA: (Hex 0xBFFF0000) Unknown system error (miscellaneous error).

I have another program using the same vi s (the one that works on another PC using LV 2018), but this other program does not issue any errors, but seems to acquire only zeros (even though the picoammeter detects current) when running under LV 2024.

I'm not quite sure what is going on.

Does anyone have any suggestions ?

Thanks in advance.

Chris

[cstorey]

Not really enough information provided to help you. We probably need to know at least the following..

How are you physically connected to the 6485 in both cases?  (Serial, USB-GPIB, ethernet?) 

Are both connections the same? 

Are both PC programs being run against the same 6485 or different instruments?  (If different then what is different in firmware, model #, years, etc..)

If you run the Highlight Execution for the Initialize.vi using both POs what do you see?

With more info will come better help!

Guesses...

- You didn't install NI-VISA

- improperly configured USB-GPIB adaptor.  

- Improper GPIB address specified.

- improper serial setup.

- newer version of K6485 returning a *IDN? string that the old Initialize.vi does not recognize.

[fogilvom2 · Accepted solution]

Use the VISA Interactive Control to see if you can send a basic *IDN?\n command to your device and get a response. This eliminates the LabVIEW API, etc. If you can't get it to respond, then you have a basic communication error.

[cghw]

Thankyou for your replies (cstorey and fogilvom2) and apologies for not getting back sooner. 

I am using the serial port and I have the same model of Keithley and cable types in both cases. However, just to make sure, I have swapped the cables and Keithleys between the PCs and they both work on the PC running Labview 2018 (32 bit), but not on the laptop running Labview 2024 (32 bit). I have installed VISA in both cases.

After trying with the VISA interactive Controller, I find that the problem seems to lie with the CH340 USB to serial port. I get a response on the old PC listing baud rate etc, but an error on the new PC. I will investigate further, but it might mean obtaining a different usb to RS232 adapter.

Thanks again.

Chris 

[AnalogKid2DigitalMan]

Suggest you use a USB to RS-232 converter using a genuine FTDI chipset to minimize any potential issues.

-AK2DM

[cghw]

It would seem that Windows provides its own driver for the USB-RS232 adapter even if the correct driver has been installed. What needs to be done is uninstall the driver and then re-install it using the manufacturers driver.

Chris