usb-gpib usb-serial parallel use

[mojojojo]

I have two scopes, one power meter, one spectrum analyzer, and one signal generator that I am able to control using a usb to gpib adapter. I also have a power supply that has only serial communication capability. I can talk with that using my usb to serial adapter. I want to control all these instruments from one vi. At present I can either run the power supply or do everything else. How can I talk through both usb adapters from the same vi. It seems that MAX will only allow me to use one usb to xxxx adapter at a time. Is this the case or is there a way to do it?

Windows XP Pro
Labview 7.1

Jmpnjoe of New Mexico

[JohnM 64]

Hi jumpnjoe,

You shouldn't have any trouble using a USB Serial device and a USB GPIB device at the same time. When you have them both plugged in, they should both show up in MAX at the same time, and you can open up VISA Sessions to both of them. What kind of error are you seeing? Are they only showing up in MAX one at a time? When you plug in the second one, does the first one disappear? I'm very interested in seeing exactly what is going on here, so keep us posted!

john
Applications Engineer

by the way, the 'jumpnjoe of New Mexico' signature may be my favorite one yet.

[mojojojo]

Thanks for the reply John
The problem happens when I plug the second USB to xxx device in. A popup will appear that prompts me to load the driver for that device. When I choose to load the driver, the first device becomes disabled. I'll need to go and try it again to see if it disappears in the MAX list or not. I know that my VI's running through the first device stop working and no longer recognize the instrument addresses in the VISA session box. On occasion I have received an error message indicating that LabVIEW needs to be the program in charge. I don't see that message too often and don't know how to repeat it so that I can write down the error code and the exact words in the message.
My plan at this time is to purchase a long serial cable (hope serial can work over 8 to 10 feet) and work with that one instrument through the COM port on my confuser.
I'll try it again this coming week and do a better job of documenting the problem.
Thanks again
Joe
a.k.a. - Jmpnjoe of New Mexico

[Tim Norris]

I've managed to use both 2 USB to GPIB converters (NI GPIB-USB-B) at the same time. They appear in MAX as GPIB0 and GPIB1. I'm using Windows XP and MAX 3.1.

I have tried inserting them while Labview is running, and the second device just hangs while the the VIs using the first one carry on unaffected.

I can install both while MAX is running without any problems.

Tim Norris