The advantages and features of PLC programmable controller

1. Use of flexible, strong commonality & ndash; — PLC hardware is standardized, combined with PLC products have been serialized, function module variety, the flexibility of different size and different functions of control system. In PLC control system, consisting of only on PLC terminal access to the corresponding input and output signal. When need to change the function of the control system, the programming can use the online or offline modify the program, the same PLC device used for different control object, just different input and output components and application software. 2. High reliability, strong anti-jamming capability & ndash; — Microcomputer powerful but poor anti-jamming capability, electromagnetic interference of industrial field, the power fluctuation, mechanical vibration, the change of temperature and humidity, could lead to a general general computer doesn't work; The traditional relay & ndash; Contactor control system anti-interference ability is strong, but due to the presence of large amounts of mechanical contact ( Easy wear and ablation) But life is short, the system reliability. PLC USES the microelectronics technology, a large number of switch actions are done by non-contact electronic storage devices, most of the relay and multifarious attachment replaced by software program, the long life and reliability is greatly increased, from the point of actual usage, PLC control system of MTBF generally up to 4 to 50000 hours. PLC has adopted a series of hardware and software anti-interference measures, can adapt to various strong interference of industrial field, and has the ability of fault self-diagnosis. Such as general PLC can resist 1000 v, 1 ms pulse interference, the working environment temperature is 0 ~ 60 ℃, no forced air cooling. 3. Simple interface, convenient maintenance & ndash; — PLC interface design according to the requirement of the industrial control, have strong ability of load ( Input and output can be directly with ac 220 v, 24 v dc high voltage connected) Also for the modular, interface circuit, easily maintenance replacement. Some PLC can even charged plug input/output module, not offline power outages and replace fault module directly, greatly shortened the time troubleshooting. 4. Small size, low consumption, high cost performance & ndash; — With small PLC ( TSX21) As an example, it has 128 I/O interface, can be the equivalent of 400 ~ 800 relay control function of the system, its size is only 216 & times; 127× 110 mm3, 2. 3 kg, don't take the no-load power consumption of the interface is 1. 2 w, its cost is equal to the function of relay system with only 10 ~ 20%. PLC input/output system can intuitively response field signal changes in the state, but also through a variety of way intuitively reflect the running state of the control system, such as internal working status, communication, I/O point state, abnormal status and power status, etc. , are all have marked indication, very beneficial to operation and maintenance personnel to monitor system. 5. The programming is simple, easy to learn & ndash; — PLC is geared to the needs of the user's device, PLC's designers give full consideration to the field of engineering and technical personnel skills and habits. Most of the PLC ladder diagram programming provide commonly used way and the way of simple instructions for industrial control. Programming language image intuitive, less instruction, simpler syntax, don't need special computer knowledge and language, the persons with certain electrical and process knowledge can be mastered in a short time. Using the special programmer, can easily view, edit, modify user program. 6. Design, construction, commissioning period is short & ndash; — Using relay & ndash; Contactor control to complete a project, must first according to the technological requirements to draw electrical schematic diagram, and then draw the relay panel ( Ark) Layout and wiring diagram, etc. , to carry on the installation and debugging, after the change is very inconvenient. And PLC control, due to its software to realize control, the hardware circuit is very concise, and for the modular building block structure, and commercialization, so the only according to the performance, capacity ( Input and output points, memory size) Choose assembly, and a large number of specific can also be used in the PLC programming work before the arrival of the goods, and thus shorten the design cycle, so that the design and construction at the same time. Because the software programming to replace the hard wiring to realize control function, greatly reduce the heavy install wiring work, shorten the construction period. PLC is programmed control task, the convenient user industrial programming language, and has the function of force and simulation so the program design, modify and debugging is very convenient, which can greatly shorten the design cycle and was put into operation.