USB to RS232 (NI adaptor or not)

[js777]

Hi:

I have to use a USB-RS232 adapter to link my notebook to a device for the controlling.
The controlling will be done through LabView with the VISA  library.

However, I found the price for USB-RS232 adapter varies a lot.
NI has one (http://sine.ni.com/nips/cds/view/p/lang/en/nid/12844), over 100 pounds, whilte there are many other USB-RS232 adapter just cost 10-30 pounds from other places.

What I wonder if, what make NI's USB-RS232 adapter this price?
Is there any compatibility issue (only NI's adapter is compatibile to LabView?) or other driving issue I should be aware of?

I just want to figure out the difference between NI's adapter between other cheaper adapter before I make the purchase (but I do want to avoid the compatibility issue)

Many thanks
Regards, Jhensi

[Wayne.C · Accepted solution]

Jhensi,

There are many companies that make USB-RS232 adapters that will work with LabVIEW using NI-VISA.  The problem is that the drivers for some adapters are not fully compliant with the RS232 spec.

Another thing to consider is isolation.  If you will be in an industrial environment you may wish to consider an isolated USB-serial adapter.  I personally use adapters from  NI and  B&B Electronics.  If you search the forums you will find other manufacturers mentioned as well.

[Dennis_Knutson · Accepted solution]

What I've used with great success are adapters that use the ftdi chipset. Less so with prolific chips.

[crossrulz · Accepted solution]

I've been using the TRENDnet TU-S9 with a lot of success over the last year.  Just make sure you get the latest drivers from TRENDnet and then use VISA to talk over the serial port.

[js777]

Hi All:

Many thanks for the reply.
So it all comes down to if the driver is well written (following the standard).
Since I dont need to make it isolated, I think I may not need to go for NI's high cost adapter.
I will try to find some other you guys just mentioned.

Cheers, js777