What Is Plc?
Nowadays, automation technology has accelerated with the increasing transition from analog systems to numeral systems. The basis for this is “programmability”. The use of devices we define as microcontrollers (or microprocessors) and PLC (Programmable Logic Controller) systems in the industry has increased and a new functional paradigm has emerged. PLC is a microprocessor that processes the information it receives from sensors in its own system and transfers it to the work elements. The general purpose includes mathematical combinations and sequential operations such as sorting and counting.
The usage area of PLCs is quite wide. The first PLC was produced in 1968 by Associates, now known as Modicon. PLCs are used in factory manufacturing automation, elevator systems, motor speed control, automatic packaging, robotics, vacuum facilities, energy systems, etc. They are resistant to heat, temperature, mechanical impact and vibrations.
The most commonly used language in PLC programming is Ladder. This is a graphical language similar to the ladder diagrams of electro-mechanical relays.
Structure And Equipment Of Plc System
PLC consists of 3 main parts: input module, central processing unit and output module. The central processing unit is the brain of the PLC system. This unit is the card where the system software is stored and processed. The entire program is located here and controls are provided here. Apart from this, there are memory elements that store written programs. This is where information about input-output modules is stored.
There is also a power supply. Its purpose is to provide the voltage required for the operation of the electronic circuits in the system. This power supply energizes all cards except input-output cards in the PLC.
Finally, as a programming device, there is a special computer designed to create programmable control systems in computer form and suitable for PLC programming. This is to optimize production processes. The operator panel can function in an environment where there is no computer.
There are remote terminal units outside the PLC area. These collect data from devices in the field, then process this data and transmit it to the control center, allowing operators to monitor and control it in real time. In order for terminal units to work correctly, they must be programmed carefully and correctly. Programming determines how remote terminal units respond to field devices, what data they collect and how they transmit. In this context, just like PLC, remote terminal programming is at the center of industrial automation.
Remote terminal units and PLC are two basic elements of industrial automation, but they have different tasks. PLC is a process optimization and control device and is used directly in the local area, that is, in the field. Remote terminal units, as the name suggests, are optimized for remote data collection and transmission. Additionally, PLCs are simpler to program and have fewer input and output points. Remote terminals are designed to control more complex systems and have more input and output points.
Important Points In Plc Selection
First of all, the central processing unit should be selected according to the size and needs of our system. The number of inputs and outputs must be able to meet the needs of the system in the long term. The power supply must be at a voltage level that allows us to get the maximum output current according to the power characteristics of the cards inside the PLC. The tracking system, installation, programming and wiring should be as simple as possible. Apart from this, remote access should be allowed and it should be as easy as possible to test whether the programs are working correctly.
Siemens Plc
It is the most widely used PLC systems brand in our country. SIEMENS PLC is manufactured from high quality materials and is resistant to harsh environments. Suitable for long-lasting performance. Due to their modular structure, they have the ability to change and expand the system.
SIEMENS PLC offers high performance with its fast processors and high storage capacities. In this way, they can easily perform complex and fast operations. Apart from this, it has a user-friendly interface and software in terms of programming and configuring the device.
SIEMENS PLC can easily integrate with different automation components. This is ideal for a wide automation system and efficiency.
SIEMENS PLC has an important place in the future of industrial automation.