What is a PLC ?
What does PLC Automation mean?
A PLC (programmable logic controller) is a digital computer used for industrial automation to automate different electro-mechanical processes. It was introduced to eliminate issues such as high power consumption that arose from the use of relays to control manufacturing processes. It consists of a programmed microprocessor whose program is written on a computer and later downloaded via a cable to the PLC. The program is stored in a non-volatile PLC memory.
How does a PLC work?
The programmable logic controller receives information from connected input devices and sensors, processes the received data, and triggers required outputs as per its pre-programmed parameters. Based on its inputs and outputs, a PLC can easily monitor and record runtime data like operating temperature, machine productivity, generation of alarms when a machine fails, automatic start and stop processes and more. This means that PLCs are robust and flexible manufacturing process control solutions that are adaptable to most applications.
PLC hardware components include:
- CPU: checks the PLC regularly to prevent errors and performs functions like arithmetic operations and logic operations.
- Memory: system ROM permanently stores fixed data used by the CPU while RAM stores the input and output device information, timer values, counters, and other internal devices.
- O/P section: this section gives output control over devices like pumps, solenoids, lights, and motors.
- I/O section: an input section that tracks on field devices like switches and sensors.
- Power supply: though most PLCs work at 24 VDC or 220VAC, some have isolated power supplies.
- Programming device: is used to feed the program into the processor’s memory.
Application of PLC
1. Industrial Applications
In industrial automation, PLC performs a wide variety of manufacturing production, monitoring machine tool or equipment, building the system, and process control functions.
Automatic Drainage Water Pump Monitoring and Controlling System.
2. Power Station Applications
For the electrical power system analysis, PLC plays operation for maintenance and other main roles in the power plants and the smart grid system.
3. Commercial Applications
We can see the growth of PLC in commercial control applications. With the use of PLC, applications can easily operate without or with very minimal manpower or physical hard work.
Smart Traffic Control Signal System.
4. Domestic Applications
For the domestic purpose, PLC act as a remote operating device or automatic sensing device. We can automate some day-to-day activities with PLC.
Water Tank Level Control System, Car Washing and Parking System, smoke detector system , Automatic Door Opening/Closing System.