Reading Words from Temperature Controller Registers Using Modbus

[Dennis_Knutson]

It's silly to send the idn command. That is not modbus. Have you downloaded the modbus library for LabVIEW?

[haluk]

Yes, it is installed

thank you for your help

[Dennis_Knutson]

Then that is what you should be using instead of the plain VISA writes.

[haluk]

I assume you are talking function code or "data to send"

can you show an example or guide me to where I can see one,

as you guess I am not good and limited with this protocol

[tst]

For this to work, someone needs to implement the Modbus protocol in code. Dennis is saying that people already did this and you can find toolkits which implement the Modbus protocol in LV if you search this site. Once you find and install this toolkit, you should have a VI which implements the read holding register function and you call that VI.

[Dennis_Knutson]

http://www.ni.com/example/29756/en/

There are other modbus functions available in newer versions of LabVIEW but I have not used them.

[mp2223]

Hi, 

I am new to both LabView and Modbus, but I am working on a project where I would like to be able to read the temperature from a SOLO 4848 controller. I have downloaded the DSC and Modbus library already and have looked through examples and tutorials. I made the VI below and put the error indicators in to see if I could tell what was wrong, but no errors show up. I have also included the controller protocols and data registers. If you have any suggestions for me I would really appreciate any guidance!

Thanks! 

[haluk]

 I use the attached vi and it works. I can read all of the registers etc (almost everyday I use it).

Just make sure the solo com port #, bout rate, and rest of the communication parameters matches with the software.

Try to read 4096 which is the temperature.

Also make sure your pc com port matches with the software.  You can open the block diagram and change the parameters.

let me know if you have any question.

haluk@tekusa.com