אוטומציה ובקרה – PLC – Programmable Logic Controller
A Programmable Logic Controller – PLC is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory. A PLC is an example of a hard real time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation will result.
PLCs are usually programmed using application software (SW) on personal computers (PCs). The PC is connected to the PLC through Ethernet, RS-232, RS-485 or RS-422 cabling. Most PLCs used by smartlogic when designing an automation and control systems are the Siemens PLC and Allen Bradley‘s.The programming SW allows entry and editing of the ladder-style logic. Generally the SW provides functions for debugging and troubleshooting the PLC software, for example, by highlighting portions of the logic to show current status during operation or via simulation. The SW will upload and download the PLC program, for backup and restoration purposes.
The functionality of the PLC includes sequential relay control, motion control, process control, distributed control systems and networking. The data handling, storage, processing power and communication capabilities of some modern PLCs are approximately equivalent to desktop computers.
The PLC unit consists of separate elements, such as power supply, controller, relay units for in- and output
The main difference from other computers is that PLCs are armored for severe conditions (such as dust, moisture, heat, cold) and have the facility for extensive input/output (I/O) arrangements. These connect the PLC to sensors and actuators. PLCs read limit switches, analog process variables (such as temperature and pressure), and the positions of complex positioning systems. On the actuator side, PLCs operate electric motors, pneumatic or hydraulic cylinders, magnetic relays, solenoids, or analog outputs. The input/output arrangements may be built into a simple PLC, or the PLC may have external I/O modules attached to a computer network that plugs into the PLC.
Here are some examples of the PLCs used by Smartlogic: 6XV1830-0EH10, 6ES7131-4BF00-0AA0, 6ES7193-4CA40-0AA0, 6ES7134-4GD00-0AB0, 6ES7193-4CA40-0AA0, 6ES7138-4CA01-0AA0, 6ES7193-4CC20-0AA0, 6ES7590-1AB60-0AA0, 6ES7511-1AK00-0AB0, 6ES7954-8LP01-0AA0, 6ES7155-6AU00-0BN0, 1746-NO4V, 1769-L16ER-BB1B