Modbus

[crhanks]

Has anybody tried to talk to a Modbus RTU device with LabVIEW?? I can't get
the slave to respond to commands.

[pspring]

"Chuck Hanks" wrote:
>>Has anybody tried to talk to a Modbus RTU device with LabVIEW?? I can't
get>the slave to respond to commands.>

Yes. I have used it extensively for product testing. LabVIEW uses strings
as I/O to the serial port. On a string control right click and select "Hex
Display". Type your Modbus message with CRC. For the Read Port vi create
a string indicator. Right click and select "Hex Display". Write the query
to the port. Read the response.

[abrause]

http://labview.pica.army.mil/archives/vi/lv4/

Check out Modbus.zip and Eurotherm.zip for good examples
of how to do modbus with LV.

Alan

"Chuck Hanks" wrote in message
news:3a8972ec@newsgroups.ni.com...
>
> Has anybody tried to talk to a Modbus RTU device with LabVIEW?? I can't
get
> the slave to respond to commands.
>

[GuillermoP]

Hi,
The http://labview.pica.army.mil/archives/ vi/lv4/
address doesn't work anymore.
Does anyone have the Eurotherm.zip file?

If I'd like to use NI Modbus drivers, how should I connect to the device? Wich steps -indetail- are required?

Thank you!
G

[urs boegli]

Ciao Guillermo,
I think there is no NI modbus availible.
Do a search with google
http://groups.google.com/groups?hl=de&lr=&ie=ISO-8859-1&q=modbus&meta=group%3Dcomp.lang.labview
and you will get a lot of good hints.
I personally used the modBus driver from air (NL) as a base for my own solution.

Good luck
Urs

Guillermo P schrieb:

> Hi,
> The http://labview.pica.army.mil/archives/ vi/lv4/
> address doesn't work anymore.
> Does anyone have the Eurotherm.zip file?
>
> If I'd like to use NI Modbus drivers, how should I connect to the
> device? Wich steps -indetail- are required?
>
> Thank you!
> G

[Krista H]

Hi Everyone,

Just to let you know there are several ways to use Modbus with LabVIEW and LabVIEW RT. Please see this KnowledgeBase for further information.

[unclebump]

I would start with downloading portmon so you can see both sides of the serial data stream. Then download the modbus protocol guide so that you can see how the commands are created in detail. Cable wiring is also critical.

http://www.microsoft.com/technet/sysinternals/utilities/portmon.mspx

See this thread for the protocol manual.

http://forums.ni.com/ni/board/message?board.id=170&message.id=197677&query.id=96682#M197677

There are several working examples of modbus serial vi's on the forums. See my llb file in this thread.

http://forums.ni.com/ni/board/message?board.id=170&message.id=144504&requireLogin=False

[MKES]

Hi crhanks,

Try this: http://sine.ni.com/nips/cds/view/p/lang/es/nid/201711  ... it's in spanish but there should be no problem with vi's included in the library.