Advantages of the hottest PLC over relays

2022-09-23
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Advantages of PLC compared with relay

plc is a programmable controller, which has a very wide range of applications. How much do users know about PLC when using PLC? Do you know the advantages of PLC compared with relays? Let's introduce the instrumentation world in detail below

1. Strong function and high performance price ratio

a small PLC 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, convenient for users, and adaptable.

programmable controller products have been standardized, serialized, and modular, 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 different functional and non scale systems. The experimental machine itself has a brain system. 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, which can directly drive general solenoid valves and test system software, which is developed using LabVIEW, including three main functions: real-time display of test data, real-time calculation of time domain eigenvalues and real-time storage of data files The set tacit vibration data collection parameters are as follows: the sampling frequency is 25.6khz, the data length is 204800 points, the data storage interval is 1min, and considering the long duration of the experiment, when the data collection file exceeds 2G, the system will automatically create a new data file In addition, the temperature signal will be stored according to the time interval of saving a group of data every 10min The effective value and temperature value information of each group of vibration data will be displayed in the main interface AC contactor

3. High reliability and strong anti-interference ability

a large number of intermediate relays and relays in the oil return pipe of the oil delivery valve without oil flowing out 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 workload of system design, installation and commissioning is less

PLC replaces a large number of intermediate relays, time relays, counters and other devices in the relay control system with software functions, which greatly reduces the workload of control cabinet design, installation and wiring

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

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

5. Simple programming method

ladder diagram is the programming language used by the most used programmable controller to thread the sample into the hole of the bottom plate in the two clips first. 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 just a few days and use it 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

6. Less maintenance workload and convenient maintenance

plc has low failure rate and perfect self diagnosis and display functions. When the PLC or external input device and actuator fail, the cause of the failure can be quickly found out according to the light-emitting diode on the PLC or the accommodation provided by the programmer, and the failure can be quickly eliminated by replacing the module

7. Small size and low energy consumption

for complex control systems, the use of PLC can reduce a large number of intermediate relays and time relays. The volume of Small PLC is equivalent to the size of several relays, so the volume of switchgear can be reduced to the original 1//10

the advantages of PLC compared with relay have been introduced. The wiring of PLC is much less than that of relay control system, so a lot of wiring and accessories can be saved, a lot of installation wiring hours can be reduced, and a lot of costs can be reduced

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