PLCs have led to the automation of factory machines.

To further improve the productivity of the whole factory, the production system should automate the entire production process by collectively controlling the machines in each production line.
To do this, the control information and production information processed by the programmable controls of individual machines need to be integrated to control the entire production system. So, a network is used to connect the PLCs of individual machines.

The network that connects multiple PLCs to each other is called a "PLC to PLC network."

* PLC:

Programmable Logic Controller