usb to serial port convertor

[sekhon]

Hi.......

             I am working on 3 hardware which i have to run simultaneously ......... on my PC thier is one DB9 port means one serial port ...so by using rs232 cable communication is set up between pc and hardware and one hardware is also running means output is coming........Now my problem is that i have to run 3 hardware ....so, i want to know that can i use two USB to SERIAL PORT convertor .........so that 3 ports r available to me and my problem get solved ...... i don't know how to work on it ..please help me... thanks

[Broken_Arrow]

USB to Serial Port converters are very common. Check out B&B Electronics, or just surf the web, you'll find lots of sources.

[smercurio_fc]

Just make sure you don't a "cheapo" brand. If you see a specific model, search these forums to see if anyone has run into any problems with with. What software are you planning to program in?

[Broken_Arrow]

Good point smerc. Some of those $12 ones don't hang tight , or they re-assign the COM number every time the computer is rebooted  .

[sekhon]

Thanks for your suggestion .......I am working in labview .....please tell me how to work on USB to serial converter in labview ...means that i don't have any idea that how i start work on it ......i have to run 3 hardware simultaneously  so please help me..

[Dennis_Knutson]

Look at the basic and advanced srial examples.

If you are using norma; RS-232. you will need three converters - one for each instrument.

[sekhon]

thanks for your help ......i want to know that if i am using 3 usb to serial convertors then how i select particular port mean to say that if in labview just with the help of visa resouce name shall i  select particular  port or i have to configure the usb port also .....please help me in this regard because i know that how with the help of one port serial communication(present in cpu) is made .......but due to use of 3 port i am getting confused .......please send me example that how 3 port selection is made individually if possible . I am extremely thankfull to you

[Broken_Arrow]

Multiple port selection is most easily achieved through a switch dedicated to switching com ports, similar to B&B's Smart Switch, or devices from Edgeport, and many others. You connect as many devices as you need to the switch, then one connection to the computer. The switching is done by a software-sent address. You just need to look at the manuals for the devices - it's not so much a LabVIEW question at this time.

[Dennis_Knutson]

If you are using 3 separate converters, you select each one with a different VISA Resource Name. Nothing else is required.

[Broken_Arrow]

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Dennis Knutson wrote:
If you are using 3 separate converters, you select each one with a different VISA Resource Name. Nothing else is required.

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He said he has one DB9 on his computer, which would indicate there is one serial port, so a multiple tap is needed. Three separate converters aren't going to do the trick, from what I understand. This should be clarified by the OP.