Access to MODBUS TCP addresses (from Raspberry Pi)

General
1

Hi friends:

I have installed Node-RED with Modbus-Package in order to connect via TCP a Kinco PLC, which is connected to a Raspberry PI.

I set up the Node Server and it connects to the master properly, but the Node Read doesn't get any data at all. Unfortunatelly, I am not skilled at Modbus protocol, and I have no response from the PLC developer, but previously he has sent a documentation to access to every specific PCL variable.

The document describes the following addesses location:

Variable Gateway Bit
A 401000 0
B 401000 1
C 401000 2
.
.
X 401002 0
Y 401002 1
Z 401002 2

The question is: what values should I assign into the Node textboxes in order to get data from any of these variables?
-Unit ID
-FC
-Address
-Quantity

I attach my flow diagram:

image
image.png1064×553 19.3 KB

Thanks so much in advance

2

Welcome to the forum.
There are 8 different “modbus packages”
https://flows.nodered.org/?term=modbus%20&type=node&num_pages=1
It’s useful if you specify the name of the modbus nodes you have installed.

3

THanks ukmoose, I have installed other types, but the result is the same: 0 values.
regards.

4

That’s great, but which one are you using?

5

I have installed "node-red-contrib-modbus" and later "node-red-contrib-modbustcp" because I have to use the TCP protocol to connect the Kinco PLC.
:wink: