USB-485 & LabView

[Chris95370]

I would like advice as to whether following design sounds doable and feasible.

I plan to use two National devices, USB-485 and USB-6003 with LabView, The USB-6003 will collect local analog data while the USB-485 will be used to collect distant analog data. The National USB-485 will communicate with custom-made, a non-National RS485 device. The National USB-485 will collect blocks of data (~100k bytes)  for display within LabView  (along with the USB3003 data).

Three (3) quick questions:

1.) Does this design sound doable and feasible.

2.) Does LabView provide drivers and a DAQ Assistant for the USB-485

3.) Any potential pitfalls or connectivity problems?

[GerdW · Accepted solution]

Hi Chris,

1.) Does this design sound doable and feasible.

Well, yes.

2.) Does LabView provide drivers

Yes.

and a DAQ Assistant for the USB-485

No.

It's a serial port, so you should use VISA functions.

3.) Any potential pitfalls or connectivity problems?

Use smaller data blocks than 100kB! Read the forum on topics about (non) usage of "Bytes at port"…

[Chris95370]

Awesome’ Thanks. Good answer!

Chris. 

[Ben]

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@Chris95370 wrote:

I would like advice as to whether following design sounds doable and feasible.

I plan to use two National devices, USB-485 and USB-6003 with LabView, The USB-6003 will collect local analog data while the USB-485 will be used to collect distant analog data. The National USB-485 will communicate with custom-made, a non-National RS485 device. The National USB-485 will collect blocks of data (~100k bytes)  ...

3.) Any potential pitfalls or connectivity problems?

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RS-485 is a transmission line

Long runs at high transfer rates demand you adhere to the specs of RS-485 including max cable length, shielding, impedance of the cable, and termination of the lines at both ends.

Failure to do so could result in something that works fine on the bench but is dodgy when used in the final solution.

There are RS-485 extenders/repeaters available from Black Box and the like.

Have fun!

Ben

[Chris95370]

Thanks for your advice. 

I’ll watch lengths and potential noise problems on the 485 lines. 

Chris.