Read from a Power Meter with Modbus

[K C · Accepted solution]

How many registers do you try to read using this command ?

Can you try register 7274 with the size set to 1 ?

Also remove the while loop from your VI and close the connection.

[Wavicle]

I get the same error, maybe I don't have communication with the power meter

[K C]

still error 56 ?

[K C]

Ok, How did you connect everything ?

Did you try to swap the two data wires ?

[Wavicle]

Yes, still error 56 but this time in the shutdown VI. 

I connected the wires as shown in the instructions of the converter I am using and swapping them gave me the same error. I attach the user manual, maybe there is something there that I don't understand and that is the problem

[Wavicle]

Hi KC,

 The error 56 disappeared,  I did what you said about closing the modbus connection outside of the while loop and right now I have connection with the device but I cannot see anything, when I run the VI the output that I have is in 0 always

[K C]

Hi,

When I look at the VI's of the library I don't see that the returned data is checked.

So it looks like anything that comes back is already an answer.

EDIT

I was looking at the wrong place. There is a check for the answer. So no error means communication is Ok !!

You can try another address to see if this helps and if there is an error.

Kees

[Wavicle]

Hi,

I made a mistake, I can read data. I don´t know if it is right because I read 60k A when the device says 0.04 A but it's something

Thanks

[K C]

Hi,

But you don't why it failed at first ?

The data you read is a float32. I think you have to translate this.

Try to read something like settings or serial number.

Kees

[Wavicle]

Hi

Yes, at first it didn't read anything because I changed one of the parameters by mistake without knowing.

It reads fine, to get the real values I need to translate the output to float32 big-endian, how can I do that?

Thanks