Modbus libraries for LabView 8.0

[unclebump]

You'll have to see if the modbus libraries actually support code 16. It may only allow function 6. Then you would have to execute multiple writes with your array of data, quantity, and addresses. I'll have to look when I get back to my desk.

[malef]

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@Khalid wrote:
Have you been able to use the TCP Modbus Slave example to write out any values succesfully?  I am able to read values into my Slave VI example, but I can't seem to be able to write values out. 

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Khalid,

try "MB Ethernet Example Slave mod1.vi" posted by me 11-21-2005 04:43 AM.
A master VI is able to read Discrete Inputs and Input Registers from this Slave.

Manfred

[Christian_nor]

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@unclebump wrote:

You'll have to see if the modbus libraries actually support code 16. It may only allow function 6. Then you would have to execute multiple writes with your array of data, quantity, and addresses. I'll have to look when I get back to my desk.

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Hi again. It now suddenly works with function code 16. I'm not quite sure what was wrong, anyways thanks for your help.

[Stabile]

Hi,
I am trying to do the same serial modbus communications procedures as are discussed in the previous posts on this thread and I am having trouble getting any responses at all. I have tried it now using the program provided by unclebump (called my modbus serial query.llb) because others on this thread have posted that they have had luck using the same program. What is happening is that I always get the timeout error from the MB serial master query part of the program. My main question is what exactly does the timeout error mean? I'm assuming it just means that no reponse was sent or recognized so there is no longer a need to wait.
I am communicating with Omega CN9600 series temperature controllers and have used a number of different modbus programs to try and communicate with them, all ending with no response in the same fashion. I have tested all of the serial cables and even sent the units back to Omega for testing and they all check out just fine. If anyone has any hints/suggestions or experience with this type of situation any help is greatly appreciated.
-Matt Stabile

[Nishant]

Hiiii, Stabile,

             I think there might be the problem in the slave, which you are using, either as you dont explain about the baud rate, there may be the Baud rate gap between the master and the slave(mean diff brates at both sides),another thingyou can verify the com port also, but i sont think its a major issue, here i am posting you a simple of the Modbus vi which is running perfectly coz i ve tried on the dofferent kind of slaves, and it is working definitely good, without ant doubts, and if you ae still not able to communicate tehn there may be a problem of modbus inplemantation in the slave also. if any of the problems again you face write to me.

Thanks,

Nishant

[Nishant]

Hiii, Manfred,

                  Can you please give me some explaination about whats happening in the vi, please do it for my convinience.

Thanks,

Nishant

Message Edited by Nishant on 01-12-2006 10:52 PM

[Nishant]

Hiii, Manfred,

          Here i am lacking of some of the basic vis, can you please suggest me how i can get the modbus TCP-IP driver, so that i can run this, i think it requires the driver, is it?

Thanks,

Nishant

[malef]

Nishant,

you will find the complete library under
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=F1582737BACF5CA8E0340003BA7CCD71

To your previous question : I did not dive deeper into the slave comm - just made the slave simulation working.
Main task is a real world comm and not a simulation.

Manfred

Message Edited by malef on 01-13-2006 09:20 AM

[unclebump]

Do you have this manual??

http://www.omega.com/manuals/manualpdf/M3751.pdf

[unclebump]

Does Omega have any kind of demo/test program for this device?? Maybe you could use this to verify that the device actually works. Then work on the labview implementation.