I have a PLC that acts as ModBus TCP Server and can manage only 1 ModBus TCP Client.
In Node Red I use the "node-red-contrib-modbustcp" library to read and write some tags (Holding register, Coil, etc) and so I use many different modbustcp-read nodes that use the same Server.
It seems that, for every modbustcp-read node, Node Red open a different connection with the Server.
In effect, PLC side, I see that first connection from Node Red is accepted and the others are refused (Node Red side only 1 modbustcp-read node is "Connected").
In Node Red I have defined only one Server.
Is it possible to force system in using only one connection?