Faced with strange communication problem

[Nikolay2013]

Hi All,

Recently faced with strange comunication problem, namely:

BASIS:

- use GPIB devices connected

- use RS-485 cobected devices in the same application with GPIB

On one PC (my with RS 485-RS 232 convertor) I without any problems connect to RS 485 devices and asked them about status

When I try to lunch LV program on other computer I faced with problem that it doesn't see COM ports (some details - I use USB COM convertor and my compter show availiable COM port as COM 😎

For other computer I see that LV allow to choose me only GPIB connection (as VISA resources ) so what should be a problem?

PS. On my PC installed IO library from Agilent as well as NI M&A and all workong well. On second computer installed the same but M&A doesn't see COM's ports - only GPIB

Does anybody advice - what is possible reason?

[WishKebab]

Hi Nikolay2013, 

For the second computer (one that can not see COM ports), are you using a USB-to-serial converter, or a PCI card?  Look up the manufacturer for your interface hardware and see if they have a driver for the device.

 Are there any "unknown device" listings in the windows device manager?  If so, you are missing the driver for your device.

[Nikolay2013]

I use USB-RS 485 convertor. And second computer install it without any errors. So situation is such:

1. Hardware manager of Win XP see installed ports as COM8 and COM9

2. Agilent IO library suit see those ports with same names (COM8 and COM9)

3. In LabView when I try to choose in "VISA configure serial port" right COM port - it does not exist (I even don't see any standard COM  ports like COM1)

I tried to unistall Agilent IO but it didn't have any effect - situation is the same

[Nikolay2013]

Problem was fixed by adding device into "VISA resourse name" as ASRLx::INSTR

But for me is not clear why this port is not present in VISA resourses names from dropping list as well as in M&A

[.aCe.]

While this document is old, I think its still relevant. Also look at the additional links at the bottom.

http://digital.ni.com/public.nsf/allkb/7691827728AF681886256F270057337B?OpenDocument