Definition and function of electrical control system
The so-called electrical control system refers to the combination of several electrical components to realize the control of one or some equipment objects, so as to ensure the safe and reliable operation of the controlled equipment.
The main functions of the electrical control system are: automatic control, protection, monitoring and measurement.It consists of three main parts: input part (such as sensor, switch, button, etc.), logic part (such as relay, contact, etc.) and execution part (such as electromagnetic coil, indicator light, etc.).
A complete coating line needs to be equipped with a scientific and reasonable electronic control system to ensure the normal operation of the coating line.
Classification of coating electronic control system
The coating process has a lot of equipment, complex structure, strict process requirements, and precise electrical control requirements.According to the configuration of coating process equipment and system, the electric control system can be divided into pretreatment, electrophoresis equipment electric control system, catenary equipment electric control system, rectification equipment electric control system, pure water equipment electric control system, air conditioning equipment electric control System, drying tunnel, RTO equipment electric control system, mechanical transportation equipment electric control system, paint transmission and mixing equipment electric control system, robot equipment electric control system, central control equipment electric control system, etc.
Structure of coating electric control system
The coating electrical control system, referred to as the coating electrical control system, generally consists of a monitoring layer, a control layer, and an equipment layer.
The monitoring layer is located on the upper layer of the network.A central control room is set up in the workshop, and computers, servers and printers are set up in the room to form a PMC system.All monitoring computers and electric control system PLC are connected together through workshop-level industrial Ethernet (Ethernet, communication protocol is TCP/IP).Monitor the running status of each controlled device in the workshop through Ethernet (referring to the system that can transmit data to the computer monitoring system through Ethernet).
The control layer is the core of the entire electric control system, and plays the role of 'connecting the preceding and the following' in the entire system.It adopts PLC as the main control unit, receives the data information (digital or analog input signal) sent from the field through the field bus, and sends corresponding instructions (output signal) to realize the control of the field equipment after calculation and processing by the CPU.At the same time, the PLC of each main control system is equipped with an Ethernet interface, which is connected to the industrial Ethernet of the workshop as an information point.
The equipment layer is the key link of the entire control system, mainly including the on-site operation station, on-site equipment detection unit (proximity switch, photoelectric switch, etc.), other on-site input devices (such as control buttons, etc.), display devices (such as indicator lights, etc.), through The field bus is connected with the PLC in the control layer, sends the input signal to the PLC, and accepts the control instructions of the PLC.
Design steps, principles and contents of coating electric control system
The purpose of the electrical control system process design is to meet the requirements for the manufacture and use of electrical control equipment.After completing the design of the electrical schematic diagram and the selection of electrical components, the overall configuration of the electrical control equipment can be carried out, that is, the design of the general assembly diagram and the general wiring diagram, and then the electrical assembly diagram and wiring diagram of each part are designed and listed. Part of the component catalog, incoming and outgoing line numbers, and technical information such as the list of main materials, and finally write the instruction manual.
1. The design principles of the coating electric control system include the following four points:
(1) Maximize the realization of the coating production and process requirements for electrical control circuits;
(2) On the premise of meeting the production requirements, strive to make the control circuit simple and economical;
(3) Ensure the reliability and safety of the control line work;
(4) Easy to operate and maintain.
2. The basic contents of coating electrical control system design include:
(1) Draw up the electrical design assignment;
(2) Determine the electric drive scheme and control method;
(3) Select the motor capacity and structure;
(4) Design the electrical control schematic diagram and calculate the main technical parameters;
(5) Select electrical components and formulate a list of electrical components;
(6) Compile design calculation instructions.
Among them, the electrical schematic diagram is the central link of the whole design, because the electrical schematic diagram is the basis for process design and formulation of other technical materials.