RS232 communication with cDAQ

[djroseman]

Hello,

I am about to commence a project which will require my LabVIEW application to communicate with an RS232 device.  I am planning on using an Ethernet 4-slot Compact DAQ module, but can't see a way to connect through.

Is this possible? Is there a C-Series module I can buy for RS232 comms?

Dave 

[MrHappyAsthma]

Perhaps an NI Engineer would be more suited to answer this question, but I believe the NI 9870 should work for you.  (It is technically for cRIO, but if I recall correctly, the cDAQ uses the same sized modules so they are interchangable.  Please correct me if I am mistaken!)

EDIT:

Here seems to confirm its only compatible with the cRIO: http://www.ni.com/white-paper/8136/en/

So perhaps this module is only cRIO exclusive.  Could someone with more experience or NI connections check this for me 😄

[RavensFan]

I don't think that will work.  I believe that module requires a controller (such as the cRIO) with VISA installed on it so it can communicate.  A cDAQ doesn't have a controller.  It is a package of  "dumb" data acquisition modules.  The code for communicating with a cDAQ runs on a PC, and I don't think the VISA drivers on a PC are able to communicate "through" the compact DAQ to a serial module.

If this module was able to work with a cDAQ, I'm sure it would mention it somewhere in the specifications or manuals.

[Hooovahh]

So you mention you have a ethernet cDAQ.  Would it then be possible to add an ethernet switch, and a Ethernet to Serial device?  I have never used one but it appears that a quick google search finds lots of modules that can take ethernet from an RJ45 and convert it to RS232 in a DB9.  Here are a few links.

http://www.perle.com/products/RS232-to-Ethernet.shtml

http://www.lantronix.com/device-networking/embedded-device-servers/xport.html

http://www.bb-elec.com/Products/Ethernet-Serial-Servers-Gateways/Ethernet-Serial-Device-Servers.aspx

http://www.digi.com/products/faceted?keywords=products/serialservers/

[djroseman]

Thanks for all the responses...

It's a pity that you can't use the PC RS232 port and then pass the data through to the LabVIEW application, that would have been ideal.  I looked into the serial to ethernet converters, that could be a reasonable cost solution..

Thanks

Dave

[GerdW]

Hi Dave,

why can't you use the PC's RS232 port - or any cheap USB-2-RS232 thumb?

[djroseman]

That would be a good solution GerdW, but I have no idea how to acheive it - I haven't really done a serial communication application before, would someone be able to point me towards a helpful white paper / tutorial / sample code for doing this?

--dave

[GerdW]

Hi Dave,

start LabVIEW. Go to help menu and start the example finder. Look for those "serial read and write" example VIs…