USB -RS232

[vishnu]

Hi

I am trying to read data from a sensor connected to the comp thru a serial(Sensor) - USB(Computer. The problem is Labview 7.1 doesn't recognise my COM port assigned by the computer ie., the COM port to which my sensor is conected doesn't show up in the VISA resource Name control. I updated the drivers to NI VISA 3.3. Still the problem exisits. Is there some thing that am not doing???


vishnu

[Meister]

Hi,

To communicate to a device with NI-VISA you need to create the .inf file that will bind the NI-VISA driver to the device. Fortunately, the NI-VISA package has a utility called Device Driver Development Wizard that automatically generates the .inf file, if you provide the appropriate vendor and model numbers.

The following tutorial will guide you on how to do this:

Using NI-VISA 3.0 to control your USB device

Regards

Anders M
National Instruments DK

[vishnu]

Hi Anders

I am not using a USB board on the computer. I am using SERIAL-USB adapter. The USB is connected to the USB port on the computer.The computer recognises the USB - Serial Port and assigns it a name. But that port wouldn't show up in my Control.

[Meister]

Vishnu,

So if I understand you correctly, you are connecting a serial device to your USB port!?!
Is the device from NI or another vendor? What drivers have you installed?
Have you tried installing NI-Serial?

Regards

Anders M
National Instruments DK

[LV_Pro]

Your system is seeing the adapter, just not MAX? Have you tried the function key "F5" while in Max to force a refresh of its list? I have used these adapters a number of times (laptops are coming without serial or parallel ports these days) and didn't seem to have a problem, just bought them retail (different brands) and plugged them in. Did you try a different USB port, to force Windows to "recognize a new device" and reinstall the drivers? One problem with USB devices is that if the OS doesn't install its driver correctly the first time it is sometimes difficult to get it to undo it so that you can try again without going into the registry ("Danger, danger Will Robinson!").
Does Hyperterminal see it? If so does it work correctly (loop it back by connecting pins 2 and 3 together at the RS232 side, then chars typed in hyperterm should show up on the screen). If it works in hyperterminal then we probably have to try thinking of non-OS issues. Just remember to close hyperterm before trying other stuff (Windows won't share the resources)


Good Luck,


Putnam Monroe

[TongY]

Those are very good advises from Putnam. Besides them, you can always check the Device Manager and see if your USB-Serial Adapter is listed there and functioning correctly.

In MAX, the USB layer is transparent to uses, you will only see COM1, 2,... under Device & Interfaces just like normal serial ports. Open a VISA session and see if you can do a loopback test on one of the ports.

If the adapter you used if from NI, you will need to install NI-Serial as well as NI-VISA.