GPIB-serial port conflict?

[acca]

Hi all!

I am quite a beginner in labview. I encountered a quite strange problem and I would like to have a piece of advice from you.

In my project I need to control a syringe pump and to perform some electrical measurement interfacing with the Agilent 4156C SPA.

So I developed a Labview program to control the syringe pump. the pump is connected to my laptop through an USB to serial adapter. The program just sends strings of commands through the serial port to control the pump.The program is perfectly working, in the sense that I can see the COM port and I can communicate with the pump to do whatever I want.

Then I developed a program to control via a GPIB cable the Agilent 4156C. Also this program is perfectly working without problems. But since the first time I connected the GPIB cable to my laptop, Labview seems not to recognize anymore the COM port through which I controlled the pump. Basically I cannot see the COM port when I open the pop up that allow the user to select the port.

At first I thought that I couldn't control both the instruments at the same time, but this is not correct, as the pump program doesn't work  even when the GPIB cable is disconnected.

Since I had some deadlines to respect, I end up using hyperterminal to control the pump and the GPIB cable to control the SPA at the same time. In this configuration everything was working. So I contented myself.

However, it happened that I had to disinstall and reinstall labview. So I re-tried the syringe pump program first. And it was working again. But then, after having connected the GPIB cable and tried the SPA program (again working perfectly...), again the pump program was not working.

Since hyperterminal works fine, it is not a big deal in my case, but, still, I would like to understand what's going on. I read all the posts but I couldn't find anything concerning this  particular problem.

Beside, the problem can be viewed also in MAX. First I could see the com port of the syringe pump, but after the first running of the SPA program, it cannot recognize anymore the COM port, giving this warning: NO VISA RESOURCES FOUND (see attached screen shot). By the way, I enabled all the passports (included the tulip one)

Thanks for your help and suggestions!

Enrico

[falkpl]

I cant remember all the details but I know I have lost the com ports on a usb to serial in the past.  I think all I had to do was to uninstall the port in device manager and replug this device in.  There should be no reason you cant use GPIB and serial on the same pc and application.

What gpib and serial converters are you using?

[Dennis_Knutson]

It is completely unacceptable to change the extension of a bmp file simply to get around the ban on posting them. You just end up getting added to the 'do not respond' list.

[acca]

Dear Dennis,

Sorry for the file extension. I am attaching the correct file.

thanks for your understanding.

Enrico

[acca]

Dear Paul,

Thanks for your advice. I will try your suggestion and let you know.

Enrico