Types of PLC
Types of PLCs
The two main types of PLC are fixed / compact PLC and modular PLC.
Compact PLC
Within a single case, there would be many modules. It has a fixed number of I/O modules and external I/O cards. So, it does not have the capability to expand the modules. Every input and output would be decided by the manufacturer.
Modular PLC
This type of PLC permits multiple expansion through “modules”, hence referred to as Modular PLC. I/O components can be increased. It is easier to use because each component is independent of each other.
PLC are divided into three types based on output namely Relay output, Transistor output, and Triac Output PLC. The relay output type is best suited for both AC and DC output devices. Transistor output type PLC uses switching operations and used inside microprocessors.
According to the physical size, a PLC is divided into Mini, Micro and Nano PLC.
Some of the manufacturers of PLCs include:
- Rockwell Automation
- ABB
- Siemens
- General Electric
- Honeywell
- Schneider Electric