Different types of modules are used by PLCs to interact with various devices and carry out particular tasks. Depending on the manufacturer and the particular application, the types of modules utilized in a PLC system might change, however the following are some typical types:
- Input Modules
- Output Modules
- Analog Input Modules
- Analog Output Modules (AOMs)
- Communication Modules
- Specialty Modules
- Positioning Modules
- Temperature Control Modules
- Safety Modules
- PLC CPU (Central Processing Unit) Modules
- Power Supply Modules
- Remote I/O Modules
Input modules connect the PLC to external devices like sensors, switches, & other input devices. These modules receive external device signals and translate them into a structure that the PLC will understand.
Output modules connect the PLC to external devices like motors, solenoids, & other output devices. They receive PLC signals & transform them into a format which can operate external devices.
Analog Input Modules
Analog input modules are used to process analog signals from temperature sensors, pressure transducers, & potentiometers. These modules transform continuous analog signals into digital values that may be processed by the PLC.
Analog Output Modules (AOMs)
Analog output modules create analog control signals that are used to control devices such as variable speed drives (or) proportional control valves. They transform PLC digital signals into analog output signals.
Communication modules allow the PLC to communicate with other devices (or) systems, such as Human-Machine Interfaces (HMIs), remote I/O devices, (or) other PLCs. These modules can support a variety of communication protocols such as Ethernet, Profibus, Modbus, and others.
Some PLC systems include specialist modules for specific operations like high-speed counting, motion control, (or) safety features such as emergency stop and safety relay modules.
These modules are utilized in motion control and positioning applications. They are capable of controlling servos, stepper motors, and other positioning devices.
Temperature Control Modules
Temperature control modules are utilized in applications requiring precise temperature control, such as industrial ovens or furnaces. They can communicate with temperature sensors & regulate heaters or coolers.
Safety modules are intended to ensure that machines and processes operate safely. To implement safety functions, they may incorporate safety relays, emergency stop modules, & safety input/output modules.
PLC CPU (Central Processing Unit) Modules
The CPU module is the PLC’s brain, containing the processor, memory, & other components required to run the PLC program and manage the system.
Power Supply Modules
Power supply modules deliver the electrical power required by the PLC & its associated modules. They ensure that the PLC system runs smoothly and reliably.
Remote I/O Modules
These modules enable the PLC system to be expanded by connecting distant input & output devices placed away from the main PLC unit.
These are certain of the most popular modules found in PLC systems. The specific modules utilized in a PLC system are determined by the application’s requirements & the offerings of the PLC manufacturer.