Host computer is a term widely used in automation control system, it usually refers to the computer system used to monitor and control the host computer (usually embedded system or PLC, etc.) in the automation control system. The host computer can communicate with the lower computer through various communication protocols (such as RS232, RS485, Ethernet, etc.), obtain the running status of the lower computer, send control commands, etc. The host computer usually cannot be used alone.
In some complex systems, the host computer may also be responsible for data processing, storage, and display, as well as interaction with other systems. For example, in the automated production line of a factory, the host computer may be responsible for monitoring the running status of the entire production line, processing production data, interacting with the company's ERP system, etc.
The host computer is a computer that can directly issue control commands, usually industrial computers, PCs, touch screens, etc. Lower computerIt is a computer that directly controls the equipment to obtain the status of the equipment, generally PLC, single-chip microcomputer, etc., and has a more reliable and unique communication protocol. The upper computer and the lower computer can be simply understood as the relationship between control and control. The command issued by the upper computer is first given to the lower computer, and the lower computer interprets the corresponding timing signal according to this command to directly control the corresponding equipment. The way in which the two machines communicate generally depends on the lower computer, the upper computer and the lower computer can be converted.
The author's view is that PLC, as a typical lower computer, is a cooperative relationship with the upper computer, and the existence of the upper computer is not to replace PLC. In a control system, the PLC acts as the main control body, collecting data, running programs and completing many control functions. If you really don't want to use PLC, the host computer can also achieve some simple logic control.
The PLC is mainly composed of three parts: input and output (IO), logic control (program) and external interface (communication). If you want to use the host computer to replace the PLC, the IO part of the PLC can use the IO acquisition card, the PLC logic control can be changed to the host computer ** to realize, and the communication part of the host computer itself has, so as to achieve a simple device control.
Although it is feasible to achieve equipment control through the host computer, it is not necessarily the best solution. PLC (full name programmable logic controller) mainly realizes logic control, while the host computer realizes upper-level control through communicationThe real-time logic judgment and control of PLC is better than that of the upper computer.
In common practical applications, the host computer usually has the following characteristics:
Data communication: The communication between the upper computer and the lower computer is usually carried out through various communication protocols, including but not limited to RS232, RS485, CAN, Ethernet, etc. These communication protocols define the data transmission format, rate, and verification method to ensure that the data can be accurately transmitted between the upper computer and the lower computer.
Data processing: After the upper computer receives the data sent by the lower computer, it will carry out the necessary data processing. This may include data decoding, validation, transformation, statistical analysis, etc. For example, the host computer may need to convert the received raw data into physical quantities such as temperature and pressure, and then perform statistical analysis to facilitate the user's understanding and use.
Control command issuance: The user sends control commands to the host computer according to the needs on the upper computer interface. These commands are usually entered by the user through the user interface of the host computer, or they may be automatically generated by the host computer according to some algorithm. The host computer will encode these commands into a format that the lower computer can understand, and then send them to the lower computer through the communication protocol.
User interface: The host computer will usually have a user interface that is used to display data and receive input from the user. The user interface may be a graphical interface or a command-line interface, depending on the needs and complexity of the system.
Data storage: The host computer can store the collected data for subsequent analysis and decision-making.
System interaction: In more complex systems, the host computer may also need to interact with other systems, such as the ERP system of the enterprise, to realize the sharing and management of production data.
According to the functional diversity of the host computer, it has a wide range of applications in many fields and industries, and all aspects are closely related to our work and life.
Industrial automation: In the industrial production line, the host computer can monitor and control various equipment in the production process in real time, such as sensors, actuators, robots, etc. Through real-time monitoring and control of equipment, production efficiency can be improved, production costs can be reduced, and product quality can be ensured.
Intelligent transportation system: In the intelligent transportation system, the host computer can monitor and control traffic lights, surveillance cameras, road sensors and other equipment in real time to realize the optimal scheduling of traffic flow and improve the efficiency of road traffic.
Building automation: In intelligent buildings, the host computer can monitor and control air conditioning, lighting, security and other systems in real time to achieve energy conservation and safe management.
Environmental monitoring: In the field of environmental monitoring, the host computer can collect and process various environmental parameters in real time, such as temperature, humidity, air pressure, pollutant concentration, etc., to achieve real-time monitoring and early warning of environmental quality.
Power system: In the power system, the host computer can monitor and control power plants, substations, transmission lines and other equipment in real time to achieve stable operation and optimal scheduling of the power system.
Medical equipment: In the medical field, the host computer can monitor and control various medical equipment in real time, such as ECG monitors, ventilators, infusion pumps, etc., to achieve real-time monitoring of patients' vital signs.
Internet of Things (IoT): In the field of Internet of Things, the host computer can monitor and control various smart devices in real time, such as smart homes, smart factories, smart agriculture, etc., to achieve interconnection and intelligent management between devices.
These application scenarios are only a part of the application of the host computer, in fact, the host computer also plays an important role in many other fields and industries. With the development of science and technology, the host computer will play its advantages in more fields, bringing us more convenience and value.