Getting error "VISA: (Hex 0xBFFF0011)" with a USB

[Dennis_Knutson]

I'm sorry but I don't believe you when you say the devices don't show in MAX when connected. When they DON'T show is when you get the error you mention. You don't have to 'input' (whatever that means) then into MAX. They will appear when connected and disappear when you unplug and they HAVE to be listed in MAX in order for you to LabVIEW and VISA. After connecting you may have to wait or force MAX to rescan for devices.

Why are you constantly connecting and reconnecting? Why can't you leave both in and use different com port aliases? That would be the most robust solution.

[Throggdor]

Dennis you were correct, when I refreshed the device list COM4 popped up.

So maybe the error isnt when I'm trying to connect the new device but a problem that occurs when I disconnect the previous device.

As to the why am I connecting and reconnecting. That has to do with how the device works, the only time the USB is connected is during calibration, through the rest of the test cycle the USB has to be disconnected otherwise the device thinks its being calibrated and wont function normally.

The tests would be run as part of normal production so the devices being tested would change, so would which side is connected first and since I'm not sure if or how I can assign a COM port to a specific USB port on the system. I went with letting each one take turns the calibration only takes a 10 maybe 15 seconds so it didn't seem a large inconvenience. Though maybe I should look into it more if you really think that would solve the problem.

Your help is greatly appreciated.