Advantages of the hottest PLC over relay circuit

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Advantages of PLC over relay circuit

1 Strong function, high performance price ratio

a small machine has hundreds of programming components for users, which has strong functions and can realize very complex control functions. Compared with the relay with the same function, it has a high performance price ratio. Programmable controller can realize decentralized control and centralized management through communication

2. The hardware is complete, user-friendly and adaptable. The programmable controller products have been standardized, serialized and modularized, and are equipped with a full range of hardware devices for users to choose from. Users can flexibly and conveniently configure the system to form systems with different functions and scales. The installation and wiring of the programmable controller is also very convenient. Generally, the external wiring is connected with the wiring terminal. PLC has a strong load capacity and can directly drive general solenoid valves and AC contactors

3. High reliability and strong anti-interference ability

a large number of intermediate relays and time relays are used in the traditional relay control system. Due to poor contact of contacts, it is easy to have faults. PLC uses software to replace a large number of intermediate relays and time relays, leaving only a small amount of hardware related to input and output. Wiring can reduce 1/10--1/100 of the mutual relay control system, and the faults caused by poor contact of contacts are greatly reduced

plc adopts a series of hardware and software anti-interference measures, which has strong anti-interference ability, and the average time between failures reaches more than tens of thousands of hours. It can be directly used in industrial production sites with strong interference. PLC has been recognized by the majority of users as one of the most reliable industrial control equipment

4. The design, installation and debugging workload of the system is less

PLC replaces a large number of intermediate relays in the relay control system with software functions. Another PA ⑴ 1 powder material is also in the certification process. The time relay changes 1 extensive plastic granulator into a combination, intelligent plastic granulator, counter and other devices, which greatly reduces the design, installation and wiring workload of the control cabinet

plc ladder program generally adopts sequential control design method. This programming method is very regular and easy to master. For complex control system, the design time of ladder diagram is much less than that of the circuit diagram of relay system

plc user program can be simulated and debugged in the laboratory, the input signal is simulated with a small switch, and the state of the output signal can be observed through the LED on the PLC. After completing the installation and wiring of the system, the problems found in the field unified commissioning process can generally be solved by modifying the program, and the commissioning time of the system is much less than that of the relay system

simple programming method

ladder diagram is the programming language of the programmable controller with large load, fixture, strain measurement and safety performance. Its circuit symbols and expression are similar to the relay circuit schematic diagram. The ladder diagram language is intuitive and easy to learn and understand. Electrical technicians who are familiar with the relay circuit diagram can be familiar with the ladder diagram language in a few days, And used to compile user programs

ladder diagram language is actually a high-level language for users. When the programmable controller executes the ladder diagram program, it uses an interpreter to "translate" it into assembly language and then execute it

less maintenance workload, low failure rate of convenient maintenance, and perfect self diagnosis and display functions. Or when the external input device and actuator fail, the cause of the failure can be quickly found out according to the LED on the or the accommodation provided by the programmer, and the failure can be quickly eliminated by replacing the module

small size, low energy consumption

for complex control systems, the use of PLC can reduce a large number of intermediate relays and time relays. The small size is equivalent to the size of several relays, so the volume of the switchgear can be reduced to the original wiring is much less than the wiring of the relay control system, so it can save a lot of wiring and accessories, reduce a lot of installation and wiring hours, and reduce a lot of costs. Learn hard and do well

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