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Control of AC Motor through VFD with Modbus communication via Labview

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Hi Alex,


mind to share your solution so others can benefit from it!?

Best regards,

using LV2020 on Win8.1+cRIO
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Message 31 of 35


The idea was to understand both the VFD Manual and how Modbus works.

So as I said the VFD manual has the addresses in Hexadecimal, but you need only few of them.

What I changed was that I didnt put the 06H, because this is the <<Code>> to write the Modbus, but by having the ModBus <<Write Register Holding>> it do it automatically.

So inside the While Loop you just need to add the address to run the motor which for my case was 2000H and 0002H.

Again Thank you!!


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Message 32 of 35

Dear GerdW,

I have another question, if its possible to answer. The VI that I created for the motor, I added it inside on another VI which is used to get data from sensors via a NI USB. 


There are now two while loops, one to get the data via NI USB and another which is to control the motor.

My problem is that when I am running the VI, I am not getting anymore the data from the sensors, and only the motor is working.

Also another issue is that I cant stop/abort the VI..

Any thoughts on that?


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Message 33 of 35

Hi Alexis,


@Alexis_Koul wrote:

Any thoughts on that?

Sure: when your code does not work as per your requirements then your code implementation is most probably wrong!

Unfortunately you forgot to attach your code…


(I guess the main reason is you forgot to "THINK DATAFLOW!" - it's explained in the "starter" section of the LabVIEW help.)

Best regards,

using LV2020 on Win8.1+cRIO
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Message 34 of 35

Ok problem fixed.

Was not <<Think Dataflow>> issue.


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Message 35 of 35