Node-red modbus


#1

I am trying to turn on a LED using node-red.
I have attached a LED to a PIN in PLC ( %Q0.0) .
I have made the configuration in modbus-write node accordingly as shown in screenshots below. but Its not working for some reason.
any help is appreciated.

with warm regards

This is the flow.
I have used a trigger node for sending high for 3 seconds.

This is the configuration for modbus-write node. ( Address 1 corresponds to %Qx0.0 in my openPLC )


#2

I see that you asked the same question in OpenPLC forum a couple of days ago.

Your statement that "Address 1 corresponds to %Qx0.0 in my openPLC" conflicts with the reply you received.

Did you try changing your Modbus address in Node-RED contrib node for testing ?

%Qx0.0 in OpenPLC = Modbus address 0 in modbus contrib node.

Or perhaps trying to use for instnace %Qx0.3 in OpenPLC and Modbus address 3 in modbus contrib node ?

There are many other posts in OpenPLC forum explaining config , using pins in raspberry pi , priority of ladder logic over Modbus, etc...


#3

Thanks it worked. :wink: