SIEMENS 10kV-20kV Switchgear Series Product Standardization Upgrade Program
China Southern Power Grid has accelerated the pace of development of urban distribution networks focusing on Shenzhen, Guangzhou and other central cities. South Network requires that by 2020, the automatic coverage of the distribution network in the downtown area of ​​the South China Network must reach 90%, and the distribution automation upgrade must also be the focus of investment in the future, and the market is vast.
Smart grid overall planning and construction requirements:
(1) The A+ and A-type power supply areas are mainly constructed in the mode of “optical fiber + three remote†mode and the centralized automation mode of the main station.
(2) Type B, C, D, E power supply areas need to carry out the construction of distribution automation, but focus on the use of local feeder automation methods to deal with faults, the use of fault indicators to detect fault location, using two remote mode, wireless Public network-based construction mode.
(3) Distribution network automation promotion ideas: Intelligent distributed feeder automation is promoted in areas with high grid levels and high reliability requirements;
With the advent of the electrical network equipment automation era, traditional manual operations are undergoing major upgrades and transformations to automated intelligent manufacturing. The traditional economic model has become extremely urgent regardless of the speed and error control mechanisms. Industrial equipment and IT equipment, such as power grids, have become important infrastructures for the information and communication industry. While entering a period of rapid development, they have undergone changes in product architecture, manufacturing model, and industrial ecology. The integrated system of electrical switchgear is the cornerstone of the modern industry to realize the intelligent automation module of distribution network.
The bottleneck of the distribution network caused by the long-term low level of equipment information seriously restricts the upgrading of the city's power system and the application of new technologies. It is imperative that the technical upgrading of electrical equipment in the distribution network is imperative.
First, the development trend of electrical switchgear from standardization to customization
Traditional electrical switchgear manufacturing is merging the production of internet of things and big data, and the integration of information technology and industrial equipment. Industrial Internet of Things is a technology that connects machines and people. It does not directly affect the product manufacturing process. To achieve large-scale, low-cost customized production, it also needs to be combined with specific manufacturing technologies. Intelligent manufacturing of electrical equipment is the “Internet industry†system formed by the integration of concepts such as “Industry 4.0â€, “Industrial Internetâ€, and “Internet+,†which is to realize large-scale and customized production methods with intelligent manufacturing, thereby promoting electrical switching equipment. The intelligent development. It is not difficult to find that the informatization of switchgear in the future has become an inevitable trend when the Internet is used to comprehensively review the manufacturing market of electrical equipment.
Therefore, switching equipment manufacturing will realize large-scale personal customization, and the excess capacity of equipment will no longer exist. This will change the traditional industrial development model of large-scale production, standardized manufacturing, and low-cost expansion. Intelligent electrical switch equipment traceability technology, sensor technology and other new generation of information technology industry standardization hot spots, so that the cabinet factory to obtain more sustained and vigorous vitality.
Second, high-end equipment customization and general equipment standardization
1. General equipment standardization
General equipment standardization is conducive to the organization of large-scale production of standard parts, easy to ensure product quality, save materials, reduce costs; improve the interchangeability of standard parts to facilitate the operation and maintenance of future equipment. The generalization of equipment refers to the use of components of the same structure and size in different types of products or similar products of different specifications.
General equipment adopts standardized production to meet the most basic needs. The common standard codes are the national standard GB of the People's Republic of China, the mechanical industry standard JB, and the ISO standard ISO. The general equipment is to provide the same product in a serialized form, specifying a number of different outer body size and capacity series under the same basic structure or basic conditions.
General technical standards for electrical switchgear:
2, high-end equipment customization
High-end equipment has the product of high technology content and high added value. The distinctive features of the high-end equipment industry are high technology, high added value, and strong competitive advantages. High-end equipment adopts customized and personalized production to meet the needs of some equipment upgrades. The high-end equipment manufacturing industry refers to the new high-tech and high-value-added competitive equipment emerging from the general equipment manufacturing industry. From the aspect of the industry chain, high-end manufacturing industry is at the high end of a certain industrial chain.
3, the difference between high-end equipment and general equipment
The biggest difference between high-end equipment and traditional equipment is:
(1) Traditional equipment relies on traditional craftsmanship, low technical level, low labor efficiency, and high labor intensity.
(2) High-end equipment relies on high-tech advantages, and it is easy to replace traditional equipment.
(3) The biggest gap between traditional equipment manufacturing and high-end manufacturing lies in the strength of science and technology. The transformation and promotion of traditional manufacturing by high-end manufacturing is an inevitable process of manufacturing.
(4) High-end equipment adopts customized and personalized production to meet the needs of some equipment upgrades.
4, the technical characteristics of high-end equipment
High-end equipment manufacturing is a high-end link in the manufacturing value chain. It has the characteristics of high technology, knowledge, high added value, good growth, strong keyness, and high mobility. High-end equipment is based on powerful general-purpose equipment manufacturing. It extends from the traditional general equipment manufacturing to the high end of the value chain.
5, a secondary equipment division of the electrical control cabinet components
Primary equipment refers to the high-voltage electrical equipment that is used directly in the production process of producing, transporting, and distributing electrical energy. It includes circuit breakers, disconnectors, automatic switches, contactors, knife switches, busbars, transmission lines, power cables, etc. The electrical equipment that is connected to each other by a primary device to form a switch of a power distribution device or perform a process of its closing and closing operations is called a primary device. Also known as a passive component.
Most of the load switch cabinets are manually operated. The primary equipment is divided into active components and passive components.
Secondary equipment refers to the low-voltage electrical equipment needed to monitor, control, regulate, and protect the work of the primary equipment and to provide operation and maintenance personnel with operating conditions or production command signals. Secondary equipment connected to each other constitutes an electrical equipment that monitors, controls, regulates, and protects primary equipment as a secondary equipment. Also known as active components.
6, due to a variety of electrical components installed in different locations, in the formation of a complete electrical control system, it must be divided components.
(1) Design points for equipment reconciliation:
(2) Combine similar functional components together;
(3) Reduce the number of connections between components as much as possible, while placing control devices with close wiring connections in the same component;
(4) Separate strong and weak electrical controllers to reduce interference;
(5) In order to achieve neat appearance, electrical appliances with similar dimensions and weight can be combined together;
(6) In order to facilitate the inspection and debugging of the electrical control system, it is necessary to combine the frequent adjustment, maintenance and wearing components.
When dividing the components of the electrical control cabinet, the connection between the components, the electrical boxes, and the connection between the electrical box and the controlled device must be resolved:
7. The wiring between the various parts and components of the electrical control cabinet should generally follow the following principles:
(1) Switching electrical appliances, control board inlet and outlet lines generally use the terminal head or wiring nose connection, which according to the size of the current and the number of incoming and outgoing lines use different specifications of the terminal head or wiring nose;
(2) Electrical cabinets, control cabinets, cabinets (tables), and between them and the controlled equipment, connected by terminal blocks or industrial connectors;
(3) Various types of standard connectors should be used between weak control components and printed circuit board components;
(4) The connection between the components in the electrical cabinet, control cabinet and cabinet (table) can be directly connected by using the terminal of the component itself; the transitional connection line should be connected by terminal block transition, and the terminal should adopt the corresponding specification of the connection terminal. deal with.
8, install intelligent control DTU terminal equipment
Distribution automation terminals are collectively referred to as (DTU) equipment, and secondary DTU equipment is installed at various ring network cabinets, opening and closing stations (stations), and box-type substations. It is matched with the switch cabinets such as the ring network cabinet and the opening and closing station, and realizes the control of switching, closing, remote and short-range control, latching and unlocking. DTU terminal equipment can also complete the collection and calculation of the signal, voltage, current, and other data of the switchgear, to realize fault identification, isolation, and restoration and power supply to the non-fault zone of the distribution network. At the same time, it has remote data transmission and other communication functions, and can upload the collected data to the master station in real time, thereby realizing remote monitoring and control automation functions such as ring network cabinets, opening and closing stations, and box-type substations.
Third, the development of intelligent equipment based on SIEMENS 8DJH series switchgear
The Siemens series integrates electrical switchgears in sets or two, mainly based on the customer's corresponding technical standards, deploys accelerated development of smart manufacturing equipment and products, and organizes research and development of high-end smart grid equipment with deep perception, intelligent decision-making, and automatic execution.
In the intelligent production process, breakthroughs in smart core devices such as new sensors, smart measurement instruments, industrial control systems, servo motors and actuators have promoted the industrialization of intelligent switch manufacturing.
1, Siemens electrical switch cabinet system products
The Siemens family of power and process automation products provides solutions such as IT systems for electrical systems with a complete product portfolio. Siemens is committed to providing high-reliability products. With its innovative industrial design and intelligent manufacturing technology, Siemens can simplify the entire manufacturing and installation process through the modular manufacturing of the system. Improve efficiency.
Siemens offers open and flexible solutions and service architectures through the industry's most comprehensive energy management product line: in particular in the area of ​​intelligent distribution networks, the promotion of new Siemens smart grid kits, with which a large number of customized solutions can be realized. With smarter grid infrastructure and further development of stable systems, Siemens has driven information technology as its business owner. It aims at technologies such as Internet of Things, cloud computing, and big data, integrates the current global advanced production management system, and constantly develops new business models.
(1), Siemens 8DH10 switchgear and Siemens 8DJ20 switchgear are SF6 gas-insulated switchgear, the difference between the two is that Siemens 8DH10 switchgear with expansion capabilities, can be any expansion, can take PT cabinets, measuring cabinets; Siemens 8DH10 switch The cabinet is factory-assembled with an indoor metal-enclosed metal armored switchgear with a maximum voltage of 24 kV, a maximum feeder current of 630 A, and a maximum line current of 1250 A.
(2) The Siemens 8DJ20 switchgear solution is fixed and cannot be expanded. It is mostly used in outdoor switching stations, cable distribution boxes and other secondary distribution systems that do not require measurement. Suitable for a variety of substations - including in extremely harsh environmental conditions such as industrial environments, wet, sandy or dusty areas, simple outdoor substations.
(3) Overall dimensions
Siemens 8DJ20 Body Dimensions Length 1400mm Width 850mm Height 1400mm
After opening the door, the cabinet size is 1600mm high and 1600mm high
(4) Siemens 8DJH ring network cabinet
All insulating sleeves used for electrical and mechanical connections are welded to the air chamber. They do not use any type of sealing ring or plastic sealing device, which fully guarantees the airtightness of the entire air chamber. Temperature-compensated pressure indicating devices are completely unaffected by the environmental climate. The use of a single-blade three-position load switch eliminates the possibility of simultaneous grounding of the load switch in the closed state from the mechanical principle.
The load switch operation hole on Siemens 8DJH ring main unit panel has a toggle selection device to select the correct operation needs, and can be locked separately for each position of the padlock to avoid misoperation as much as possible. The load switch is a rotary type, the magnetic coil is extinguished, and a fast grounding switch is used. The product is maintenance-free for life, with a service life of up to 30 years.
The main technical parameters
a. Rated voltage: 12kV, 24kV
b. Rated current: 630A, bus current: 1250A
c. Rated short-time withstand current: 20A 25kA
d. Mechanical life: Circuit breaker: ≥ 10000 times, load switch: ≥ 5000 times, earthing switch, isolation switch ≥ 3000 times
e. Annual leak rate: ≤0.01%
f. Internal failure test: 1s (cable room, air box room)
g. Rated transfer current: 1750A
h. Protection degree of air box: IP67
i. Use environment: suitable for high altitude 4000 meters, low temperature area to -45 degrees
2. Standardization and Convergence Technology Upgrade of First and Second Equipment of SIEMENS Series Switchgear Products
According to the standardized design requirements of the module, a unified construction solution
After modification, it is divided into three parts:
The upper part is equipped with a remote communication terminal controller to make full use of the remaining space of the original cabinet
In the middle is the closing and closing operation mechanism, it is necessary to install an electric operation controller to realize the drive of a motor instead of the manual operation.
Closing operation.
First, the Siemens 8DH10/8DJ20/8DJH is equipped with an electric operating mechanism to complete electric operation with buttons. The motor operation is driven by the DC24V power supply to drive the chain or gear forward and reverse to complete the closing and closing action. If the electric operation without a gear transmission clutch is used, the manual operation will be more laborious than before the electric operation is not added.
The current transformer is installed in the cable interval below to measure the load on the cable line. Then, the remote control line, remote signaling line, and telemetry line of each loop are respectively connected to the corresponding contacts of the electric controller according to the drawing design. According to the sequence of monitoring and control points, check whether each line is connected correctly.
In this way, the modular layout of the upper, middle, and lower is formed. The compact structure saves space and makes the wiring more convenient.
After the transformation of Siemens 8DJ20 ring network switch cabinets through automation, there have been changes. In the entire renovation construction, construction must be strictly in accordance with the design process standards, and each task must be tested by the test software to solve the problems found earlier. Using Siemens' mature product platform for system value-added development, providing future-oriented switchgear automation, remote drive technology, industrial field software and services. Our principle is to make use of Siemens standardized components as much as possible, and to provide a variety of supplementary user needs with industry-specific solutions to meet the specific needs of customers in all walks of life.
3, using the system software for overall detection
After the completion of the construction, a thorough system test is required.
4, Siemens 8DJH upgrade process system testing
After the completion of the construction, a thorough system test is required.
Now complete a pre-shipment experiment according to the test system requirements.
There are four items in the public information box door open, external power loss, battery failure, low box pressure
Retract the grounding switch, turn the computer and display panel
Manual opening information status monitoring
Electric closing test
Remote control test
Factory production efficiency is high and product quality is stable.
Fourth, Siemens 8DJ20 outdoor ring counters first and second integration plan
1, Siemens 8DJ20 switchgear is SF6 gas insulated switchgear
Siemens 8DH10 switchgear and Siemens 8DJ20, series switchgear are SF6 gas-insulated switchgear, the difference between the two is that Siemens 8DH10 switchgear with expansion capabilities, can be arbitrary expansion, can take PT cabinets, measuring cabinets;
2, Siemens: 8DJ10 8DJ20 ring network cabinet basic cabinet type
Siemens 8DH10 switchgear and Siemens 8DJ20 switchgear are SF6 gas-insulated switchgears. The difference between the two is that Siemens 8DH10 switchgear with expansion capabilities, can be arbitrarily expanded, with PT cabinets, measuring cabinets; Siemens 8DJ20 switchgear solutions are fixed , It can not be expanded, and it is mostly used in secondary distribution systems that do not need to be measured, such as outdoor opening and closing stations and cable distribution boxes.
.
The 8DH20 switchgear is a type of indoor metal-enclosed metal armored single-wire switchgear that has been type-tested and assembled in the factory. The maximum voltage is 24kV, the maximum feeder current is 630A, and the maximum line current is 1250A. The Siemens 8DJ20 switchgear is suitable for a variety of substations - including in extremely harsh environmental conditions such as: industrial environments, wet, sandy or dusty areas, simple outdoor substations.
Fifth, manual switchgear structure and general technical standards
Switch cabinet technical transformation mainly includes four aspects
1. Improve the safety and reliability of the switchgear technology and equipment;
2. Through the upgrade of the equipment during the construction of the distribution network automation project, the investment is saved, and the added value of the switchgear technology is increased;
3. Apply modern computer network technology to optimize the safe operation mode of the switchgear, so that distribution network automation management can enter the modern management track;
4. Implement information production technology to solve the problem of intelligent ring network cabinets to achieve fault alarm and fault point location.
5, switch cabinet structure
Basic circuit upgrade (secondary part)
(1) Line indicator
Capacitor voltage indicator
When the line is live, the voltage indicator shows if the bushing is energized and the socket on it can be used for the nuclear phase. The system has an integrated voltage indicator (light emitting diode). For a normal operating environment, a live display device is the recommended choice. Phase identification must be performed with a nuclear analyzer.
(2) Manual nuclear phaser
The phaser shows the phase balance between the two modules. For use in capacitively coupled systems, comply with IEC 1- and/or IEC 1 regulations. The phaser must be used with the recommended voltage indicator. The role of the nuclear phaser is to confirm that the line connection is correct before the line is completed.
(3) Line fault indicator
When the short-circuit current or the zero-sequence current is higher than the preset current value, the light emitting diode on the panel of the device will flicker, and at the same time, there is a node action for remote remote signaling. When the fault disappears, the device resets (or resets via the node signal input) after the set delay.
Basic operation mechanism transformation (one part)
Six, switchgear equipment technology
The safety of power automation equipment is related to production, use, inspection, design, and manufacturing supervision. Responsible parties should perform their duties and provide technical guarantees for the safe use of complete sets of power switching equipment in accordance with the law. Standardization of safety regulations for equipment is especially important
Power equipment as a special equipment safety monitoring application of Internet of things, especially in the transformation process found that the electrical equipment in the Internet of Things business model problems - heavy concepts, light demand, lack of top-level design, business model design is not perfect and so on. Only through the standardization of equipment to solve the above problems.
1. Standardization of complete equipment has the following six basic features:
(1) Simplification, (2), unification, (3), product serialization
(4) Generalization, (5), composition, (6), and modularization.
Complete sets of equipment are automatic alarms, emergency handling, real-time monitoring of operations, maintenance inspection and information monitoring, statistical analysis of background data and other functions. The SCADA system can monitor 10kV line load conditions and perform remote control operations. Therefore, when the main network is faulty, the main network is powered off, the user is connected to the fire, and the fault is transferred, the distribution network mode is less adjusted. The “telemetry†function of the distribution network automation system allows accurate calculations of the operating mode adjustment; combined with its “remote control†function, the operating mode can be flexibly adjusted at any time.
2. Distribution network automation upgrade comprehensive solution.
The program includes: upgrading of safety control level, layout of cabinet structure, one-to-two integrated wiring, different control models and control technology for cable network automation and overhead feeder automation, standardization of switch cabinet functions, appropriate reduction of switch cabinet types, fault location technology, and standardization Construction process, software online monitoring, system safety evaluation, operation mode and protection setting analysis, late operation maintenance, system experimental testing, line fault simulation and practical training.
The task of retrofitting is to install a drive motor on the operating mechanism, which is upgraded to an electric button operation by relying on the manual lever operation. Make full use of the old equipment for upgrading, so that the primary equipment and secondary equipment can be closely combined.
Follow the standardization construction principles of China Southern Power Grid Company to meet the technical requirements for the safety, reliability and advancement of old equipment after upgrading.
The on-site acquisition equipment is mainly the contact pressure sensor of switch opening and closing position, voltage transformer, current transformer, and some auxiliary information contacts.
To increase the electric operating mechanism, it is necessary to distinguish between different performance mechanisms such as circuit breakers, breaking switches and load switches.
Modification of Remote Communication Part: It mainly determines the switching and closing position of the switch, the position of the grounding switch, the energy storage mechanism of the electric operation mechanism, and the technical principle of the motor rotation direction.
Retrofit part of remote control: Loop switch remote control closing control output. Remote closing and closing control output. Satisfy the different application functions of all switches: five kinds of commonly used switches such as circuit breakers, reclosers, inlet switch C type, outlet switch F type, and load switch.
For the development of smart grids and the automation of distribution networks, a positive and beneficial exploration was carried out. Utilizing the manual load switch cabinet on the line, through the structural process improvement of the ring network cabinet, the technical upgrading of the manual local operation to the remote automatic control operation is completed. After installing the electric operation mechanism on the manual ring network cabinet, the intelligent electronic type electric operation Controllers, PT transformers for power take-up, and CT for cable measurement, convert manually operated load switch cabinets into distribution automation terminals with “three remote†functions, and replace key nodes in distribution networks with distribution network automation terminals. The equipment realizes the overall technical solution of the manual RMU for distribution network automation technology transformation.
The key items of the retrofit program include: Structural design improvement of the RMU cabinet structure; On-site power PT customization according to the type of RMU; Addition of the electronic intelligent controller to achieve the integration of the secondary control, will be integrated The DC conversion backup battery pack, safety operation controller, and DTU are integrated. The RMU solves the AC220V power supply problem of automation equipment without a separate power PT cabinet. The installed electronic intelligent controller integrates battery, safety operation controller and DTU. It has five cores: composite sensor technology, load dispatching alarm control technology, mechanical and electrical safety control technology, integrated wiring technology and central integrated monitoring platform technology. The key technology has realized the technical upgrading of the manual switchgear cabinet and has met the safety and reliability requirements of the integrated remote control of the switchgear cabinet.
3, after the transformation is more convenient to use, in line with the operating habits of on-site personnel, enhanced electronic capabilities to improve the safety and reliability of the ring network cabinet control.
(1) There are many types of ring network cabinets, and the time to put them into operation is inconsistent. There is a big difference in the control loops. We have solved the problems of the different configurations of circuit breakers and sectionalizers in electrical operation by adding controllers. Control problems.
(2) Simplified the secondary wiring of the DTU equipment to the electric operation. According to each control unit, the connection lines are grouped reasonably, and the line direction is clear for easy maintenance and search.
(3) Upgrade by means of equipment replacement. The specific approach is to have a spare switchgear pre-debugging in the workshop, to directly replace the equipment to be changed on the spot, and at the same time upgrading and renovating the line and equipment to do the detailed overhaul.
(4) Improvements have been made in the circuit voltage and current data acquisition methods, and the composite sensor technology has been applied to effectively improve the data accuracy.
(5) Industrial Controller
Industrial equipment controllers (controllers may also be referred to as Controller Units) are master I/O devices that change the wiring of the main circuit or control circuit in a predetermined sequence, and control the start, speed, braking, and reversal of the motor.
In the control process, coupled with a suitable automatic control system to replace part or all of the operator's direct labor, the automatic completion of the design, manufacturing, assembly, installation, etc., to varying degrees.
The controller is responsible for the operation of the system. The instructions are fetched from the memory one by one. After the decoding and analysis, the control commands such as fetching, executing and storing are issued to the whole machine to ensure that the required functions of the program are correctly completed.
The controller is the sequence that decides to execute the program. Give the operation control commands required by various parts of the machine when executing instructions. Send control information according to the commands given in advance to make the whole execution process step by step.
Determine what should be done through instruction decoding (analysis), and then execute the control logic according to the determined timing by operating the I/O interface, mainly including the pulse generation register, control matrix, clock pulse generator, reset circuit, and power on/off. Road and other control logic.
The control system is implemented so that the controlled object reaches a predetermined ideal state. The control system causes the controlled object to tend to some desired steady state.
4. The control mode is divided into feed forward control, field control and feedback control.
Motor Controller
The motor controller is the main work of the industrial controller. It controls the motor to work according to the set direction, speed, angle and response time. The motor controller can be combined with a stepper motor driver and a stepper motor to form a complete stepper motor control system. It uses a computer-based programming language and has various instructions such as input, output, and counting. With features such as flexible programming and wide application range, it can be widely used in industrial control automation.
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The electromechanical driving motor controller can be divided into three different power DC motors depending on the current form. The motor automatically corrects deviations according to the different driving modes to ensure the safety of man-machine operation at the site.
5, standardized information interface
Solve the secondary equipment interface mismatch, compatibility, scalability, and poor interchangeability;
What is the electrical secondary device interface?
Electrical secondary equipment refers to the low-voltage electrical equipment needed to monitor, control, regulate, protect, and provide operation and maintenance personnel with operating conditions or production command signals for the operation of an electrical equipment.
Secondary equipment connected to each other constitutes an electrical equipment that monitors, controls, regulates, and protects primary equipment as a secondary equipment. The mismatch of secondary device interfaces means that there is a problem in the information transfer between secondary devices. In simple terms, interfaces do not match.
(1) Physical interface
Pluggable docking is the most convenient and reliable, but there will be various errors in their design and construction. Fixing the terminal label order is a good solution.
(2) Electrical Interface
In the field of automation control, with the development of distributed control systems, in the distributed control system in the industry, serial communication is often required to achieve the purpose of remote information exchange.
RS-232/RS-422/RS-485 Interface Standards RS-232, RS-422, and RS-485 are all serial data interface standards and were originally developed and released by the Electronic Industries Association (EIA). RS-232 Released in 1962 and named EIA-232-E as an industry standard to ensure compatibility between products from different manufacturers. RS-422 evolved from RS-232 and it was proposed to compensate for the lack of RS-232.
Improve the shortcomings of RS-232 communication distance and low speed.
Serial interface; Interface standards for serial communication include: rs-232, rs-422, rs-423, and rs-485. RS-232 is the earliest serial interface standard and is widely used in short interval, low baud rate serial communication. RS-422 and rs-485, which have been developed since then, are the electrical standards for balanced transmission. RS485 is a serial interface standard for balanced transmission. It has strict specifications in its electrical characteristics standard, but its communication protocol. RS-485 is one of them, it has the following characteristics: 1. Electrical characteristics of RS-485 : Logic "1" is represented by a voltage difference between two lines of +(2-6) V; logic "0" is represented by a voltage difference between two lines of -(2-6)V. The interface signal level is lower than that of RS-232-C, and it is not easy to damage the chip of the interface circuit. RS422 strengthens the anti-interference ability, makes the transmission rate and the distance greatly than the RS232. RS422 requires four transmission lines for full-duplex communication and is inconvenient to use.
(3) Bus Interface
The USB bus is an efficient, fast, low-cost, small-size, hot-swappable serial communication interface. Currently, the USB interface has been widely used in the design of electronic products. With the USB interface bus, it is easy to connect with a PC, and the USB interface can provide power for the outside world.
(4) Voltage Interface
The level shift circuit is mainly used in the direct current circuit, including the fast switching transistor mode. The user selects level transitions high and transitions low to match the desired output high logic level and low logic level. Used for signal level conversion in remote signaling and remote control. Generally, in order to improve the reliability to minimize the voltage difference, DC 24V is most commonly used.
(5) Network Interface
The grid control network gradually adopts common network transmission protocols and a variety of different network transmission channels from the original relatively closed system. The power control network channel will face various security risks.
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