Modbus TCP/IP

Projects Networking, Protocols, and Devices
1

Hello everyone,

I have some troubles with the data adresses of registers in a controller dynamic power (CDP).

The datasheet and the description of how data is stored in Modbus are in the attachements.

I should read the grid , the load and the photovoltaic powers. I'm looking for the adresses where they are stored.

Could you correct to me these thoughts ?

1-I should add +30001 to the hex adress (6A) mentinonned on the datasheet to get the adress of the

first register requested .

2-The total number of registers requested is 6 .

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2

1-I should add +30001 to the hex adress (6A) mentinonned on the datasheet to get the adress of the first register requested .

That depends on the ModBus library you plan to use. In most Arduino implementations I know you don't have to add the base register address because they use the transfered value directly which is zero based.

2-The total number of registers requested is 6 .

I don't know, based on the information you provided yet it's 2 but we are definitely missing a lot of information to answer that question exactly.

3

Thank you for the reply.

Could you please suggest some libraries with examples for modbus tcp master using wiznet w5100 ?
I'm still confused !

4

You'll find a bunch of them if you search for "arduino modbus tcp library" on Google. I looked at two or three of them while helping on the forum but doesn't use one myself as I only use ModBus RTU in my projects. None of the ModBus TCP library I've seen is well organized and structured so I won't recommend one. I remember that one of them was written so bad that it won't work even with several patches we made but I don't remember which one it was.
Also many of them are only for a ModBus slave (called server in the ModBus TCP terminology).

5

Ok thank you anyway