RS232-to-USB converter

[kpak]

I have an electronic which is connected to either RS-232 serial or USB. Since the electronic cable has a RS-232 adapter, I have to use RS232-to-USB converter to make it compatible with USB port. My LabView application runs well with RS-232 port but doesn't work with USB port. The problem is that, if I use my own laptop which has LabView 7.1 installed, the problem disappears. The electronic works well with both rs-232 and USB. However, the problem appears again in other computers regardless of its version (I tried XP and 2000). I installed NI-VISA and NI-Serial. I surely checked serial port & I/O support when making an installation file. None of the methods has solved my problem yet. Any suggestions? Thanks.

[Henrik_Volkers]

kpak,

first- check if your USB-RS232 driver is correctly installed: use 'VISA find', your system properties or look with hyperterminal if your system has an extra COM device (mostly COM3 or higher).

[JLS]

Hello,

I have a few questions, the answers to which may help you and clarify the problem:

1. Can you connect directly to your computer via rs-232... do you need to use the USB port?

2. When you say, "My LabView application runs well with RS-232 port but doesn't work with USB port." what specifically do you mean? Do you get an error? If so, what error? Can you attach a screenshot of the behavior?

3. When you plug the USB-RS-232 converter into your PC, do you have access to the RS-232 resource at all? For example, if you select, Start -> Programs -> National Instruments -> VISA -> VISA Interactive Control do you see the RS-232 resource there? Can you perform a loopback test (to do this wire pins 2 and 3, and simply write and read to that serial port)?

4. Do you have any NI Serial HW products? You won't need NI-Serial installed simply to communicate with built in serial ports (or in your case a USB-RS-232 device, which should show up as an RS-232 serial port); NI-VISA will be sufficient.

Thanks and I look forward to your repost!

Best Regards,

JLS