The application characteristics of PLC programmable controller main characteristics of industrial applications

1, high reliability, strong anti-interference ability high reliability is the key to the electrical control equipment performance. PLC as a result of the modern large scale integrated circuit IC is using semiconductor production process, on a small piece of monocrystalline silicon slice to make many transistors and resistors, capacitors and other components, and in accordance with the method of multilayer wiring or tunnel wiring components combined into a complete electronic circuit. It's on the circuit using letters & quot; 集成电路” ( Also useful text symbols & quot; N” Etc. ) Said. Technology, USES the strict production craft manufacture, the internal circuit adopted advanced anti-interference technology, has the very high reliability. The use of PLC control system, and the size of relay contactor contactor is a kind of widely used switch electrical appliances. Contactor is mainly used for frequent connected or diplomatic relations, dc main circuit and control circuit of large capacity, can remote operation, relay can realize timing operation and interlock control and all kinds of quantitative control and the pressure loss and under-voltage protection, widely used in automatic control circuit, the main control object is motor, can also be used to control other electric power load, such as electric heaters, lighting, electric welder, capacitor Banks, etc. ( The full text] System, electrical wiring and switch contacts have been reduced to hundreds or even thousands of points, one of fault is greatly reduced. In addition, the PLC with a hardware fault self test function, failure can alert information in time. In the application software, users can also into the application of fault self-diagnosis for the peripheral devices, in addition to the PLC in the system of the circuit and equipment for the protection of fault self-diagnosis. In this way, the reliability of the whole system is extremely high. 2 complete, fully functional, applicability of PLC development today, has already formed the series products of all sizes, can be used in various industrial control occasions. In addition to the logical processing function, PLC has the perfect data computing power mostly, can be used for all kinds of digital control field. A variety of functional units, make the PLC penetrated the position control, temperature control, CNC, etc. Various kinds of industrial control. Combined with PLC communication ability enhancement and the development of man-machine interface technology, use of various of PLC control system very easily. 3 easy to learn and easy to use, welcome by engineering technical personnel is PLC industrial control equipment for industrial and mining enterprises. It easy interface, programming language for engineering and technical personnel to accept easily. Graphic symbol and ladder diagram language expression and relay circuit diagram is quite close, for not familiar with electronic circuit principle and assembly language, don't understand the computer people engaged in industrial control opens the door. 4 system design work is small, easy to maintain, easy to transform ( 1) Design and maintenance of PLC use storage logic instead of wiring logic, greatly reduce the control equipment of external connection, has greatly shorten the cycle of control system design and construction, and maintenance also becomes easier, more important is to make the same equipment after change the program and it possible to change the production process. Especially suitable for many varieties, small batch production. ( 2) Installation and wiring power line, the line of control and the PLC of the power cord to the power cord is used for electrical components or equipment with power cables, generally refers to the wire on one end with an aggregate of the plug or the tail, is one of the basic components of electrical products. The power cord divided into two parts, wire and plug. And I/O lines should be wiring, isolation transformer should be used between PLC and I/O twisted-pair cable connection. Will separate PLC I/O line and power line line, such as slot must be on the same line, separate strapping communication lines, dc lines, if conditions permit, slot line best, this not only can make the space as large as possible, and to minimize interference limits. PLC should be far away from the strong interference sources such as welding machine, high-power silicon rectifier equipment and large power equipment, with high voltage electric equipment installation within the same switch cabinet. The PLC shall be far away from the power line (inside ark Distance between them should be greater than 200 mm) 。 With PLC is installed in the same cabinets inductive loads, such as large power relay, contactor coil, RC arc suppression circuit should be parallel. Had better use the separate PLC input and output line, switch and analog will separate installation. Analog signal transmission should be shielded wire, shielding layer should be end or ends grounding, grounding resistance resistance, substance of current effect is called the resistance. Resistance of small material called electric conductor, hereinafter referred to as a conductor. Resistance of the big material called electrical insulator, hereinafter referred to as an insulator. Should be less than 1/10 of the mask layer resistance. Don't use the same lines to the ac and dc output power transmission cable and cable is a kind of to information and realize the electromagnetic energy conversion of wire products. Conductor and insulation layer, and sometimes with to prevent water invasion in the tight sheath, or also add mechanical strength of the outer sheath, the structure is relatively complex, is called a cable sectional area larger products. Should try to stay away from the high tension line, the output line and power line, avoid in parallel. ( 3) The I/O connection input: input wiring generally do not take too long. But if the environment disturbance is small, the voltage drop is not big, the input wiring can be appropriately longer; Input/output line can't use the same cable, input/output lines should be separated; As far as possible the normally open contact form is connected to the input, the establishment of ladder diagram in accordance with the principle diagram of the relay, easy to read.