SM481 HollySys Input Module, Shanghai Sijian Intelligent Technology Co., Ltd. is engaged in technology development, technical consultation, technology transfer in the fields of intelligent technology, information technology, and automation technology, as well as the sales of electrical equipment, automation equipment, electronic products, communication products, and electromechanical products. Industrial automation products: PLC, DCS, sensors, frequency converters, encoders, relays, servo drives, soft starters, touch screens. Brands involved in the products include: Eurotherm, Schneider, Siemens, ABB, SICK, P+F, E+H, Yokogawa, Yamakawa, Mitsubishi, Emerson, Honeywell, FANUC, GE, Eaton Electrical, CT. Basic components of PLC programmable logic controller
SM481 HollySys Input Module, PLC programmable logic controller is essentially a computer specialized for industrial control, with a hardware structure basically the same as that of a microcomputer. The basic components are:
1. Power Supply: The power supply is used to convert AC power into the DC power required by the PLC. Currently, most PLCs use switching regulated power supplies for operation.
2. Processing Unit (CPU)
The processor is the control center of the PLC and also its core component, whose performance determines the performance of the PLC.
The processor consists of a controller, an arithmetic unit, and registers, all integrated on a single chip, connected to the input/output interface circuits of the memory via address buses and control buses. The processor's role is to process and run user programs, perform logical and mathematical operations, and control the entire system to coordinate.
3. Memory
Memory is a semiconductor circuit with memory function, used to store system programs, user programs, logical variables, and other information. Among these, the system program is the program that controls the PLC to achieve various functions, written by the PLC manufacturer and solidified into read-only memory (ROM), which users cannot access.
4. Input Unit
The input unit is the input interface connecting the PLC to the controlled equipment, serving as the bridge for signals to enter the PLC. Its function is to receive signals from command elements and detection elements. Input types include DC input, AC input, and AC/DC input.
5. Output Unit
The output unit is also a connecting component between the PLC and the controlled equipment. Its function is to transmit the PLC's output signals to the controlled equipment, converting the weak electrical signals from the processor into level signals to drive the actuating elements of the controlled equipment. Output types include relay output, transistor output, and thyristor output.
In addition to the above parts, depending on the model, the PLC also has various external devices, whose functions are to assist in programming, enable monitoring, and network communication. Common external devices include programmers, printers, cassette tape recorders, computers, etc.