PLC networks include two types: PLC control networks and programmable controller communication networks. People often do not distinguish between them and treat these two types of PLC networks as the same thing, but in fact they are different.
1. PLC control network
(1) Function
A PLC control network is a network that only transmits on/off switching signals and transmits a small amount of data at a time. Examples include remote I/O links for programmable controllers and PLC systems that exchange data via the Link area.
(2) Characteristics
Although the switching signals to be transmitted in the PLC control network are far away from the programmable controller, the programmable controller can operate on them as simply, conveniently and quickly as if it were operating directly on its own I/O area.
2. PLC communication network
(1) Function
PLC communication networks, also known as high-speed data highways, can transmit both digital and digital signals, and can transfer a large amount of data in a single communication. The operation of these networks is similar to that of ordinary local area networks (LANs).
(2) Characteristics
With the development of communication technology, PLC control networks can transmit both switch signals and digital signals. In fact, there is no boundary between switch signals and digital signals; multiple switch signals combined together constitute a digital signal.
3. Differences between PLC control network and PLC communication network
The essential difference between the two types of PLC networks is that the PLC control network operates just like a programmable controller operating its own I/O area, while the PLC communication network operates similarly to a regular local area network.
It should also be noted that people often refer to the PLC network control system in an application system as a programmable controller control network. This is in terms of application and has nothing to do with communication, so it generally does not cause confusion.
