subject: PLC advantage relative to the relay circuit relay line-PLC - Electrical industry [print this page] PLC advantage relative to the relay circuit relay line-PLC - Electrical industry
Strong function, high cost performance Within a small
hundreds of programming available to the users device, has a strong functions, can achieve very complex control functions. With the same function Relay Compared with high performance and low cost. Chapter program controller can be networked through communication, to achieve decentralized control, centralized management.
2, the hardware package is complete, the user easy to use, adaptable
PLC products have been standardized for GSM, equipped with a full range of various hardware devices for the user to choose. Users can conduct flexible system configuration to form different functions, not the size of the system. Leng-programmed controller is also easy to install and connect the general with the connection Terminal Connect the external wiring. PLC With strong load capacity, can directly drive the solenoid valve and the exchange of general contactor.
3 high reliability, strong anti-interference The traditional relay control system using a large number of intermediate relay, time relay. Because contact breakdown and prone to failure, PLC Using software to replace a large number of intermediate relay and time relay, leaving only the input and output of the small amount of hardware, wiring can reduce the inter-relay control system 1/10--1/100, poor contact caused by contact failure greatly reduced.
PLC hardware and software to take a series of anti-interference measures, has a strong anti-interference ability, mean time to failure to reach tens of thousands of hours, there is a strong interference can be used directly for industrial production sites, PLC has been the majority of users recognized as the most reliable one for industrial control equipment.
4 system design, installation, commissioning work less
PLC functionality with a software control system to replace the relay in the middle of a large number of relays, time relays, counters and other devices to control the cabinet design, installation, wiring workload greatly reduced.
PLC's ladder program generally use the sequential control design. This programming method is very law, it is easy to grasp. For complex control systems, the design of ladder longer than the relay system circuit design is much less time.
PLC's user program debugging can be simulated in the laboratory, the input signal with a small switch to simulate, through the PLC can be observed on the LED output state. Completed the system installation and wiring, the adjustment process in the field of systems problems found in general can be resolved by modifying the program, the system debug time much less than the relay system.
Programming method is simple Ladder is the most used PLC programming language, symbols and expression of its circuit and relay circuit diagram similar to the image of visual ladder language, learn to understand, familiar with the relay circuit electrical technicians spend a few days as long as the ladder can be familiar with the language and procedures used to prepare the user.
Ladder language is actually a high-level language for a user, programmable logic controller ladder in the implementation of the program, explain the procedure to use it "translated" into assembly language and then to do it.
Less maintenance, the failure rate is very low maintenance and convenient, and have perfect self-diagnosis and display. Or external input devices and the failure of the implementing agencies, according to the light-emitting diode or a programmer to provide the accommodation to identify the causes of the rapid, the method used to replace the module can be quickly troubleshooting.
Small size, low power consumption
For complex control systems, using PLC, you can reduce the number of intermediate relay and time relay, small volume equivalent to the size of a few relays, thereby reducing the size of the switch cabinet to the original wiring than did relay control system is much less wiring, it can save a lot of wiring and accessories, to reduce the installation of wiring a large number of working hours, can reduce the significant costs. Hard to learn, do comfortably
