HG/T 20700-2000 Programmable Controller System Engineering Design Specification
Some standard content:
Industry Standard of the People's Republic of China
Design Code of System For Programmable Controller
Design Code of System For Programmable Controller HG/T20700-2000
Editor: China Tianchen Chemical Engineering CorporationApproving department: State Bureau of Petroleum and Chemical IndustryImplementation date: June 1, 2001
National Chemical Engineering Construction Standard Editing Center (formerly the Engineering Construction Standard Editing Center of the Ministry of Chemical Industry) 2001 Beijing
1.0.1 This regulation is a technical regulation formulated for the use of programmable controllers (PC—Programmable Controller, PLC—Programmable Logic Controller, etc., hereinafter referred to as PLC) in chemical automatic control design. 1.0.2 These regulations apply to the PLC engineering design of newly built chemical enterprises, and the scope of application is as follows: formulate the implementation plan of PLC in industrial process monitoring applications; determine the basic configuration of the PLC hardware system;
prepare the PLC technical specification;
prepare the PLC inquiry;
submit the external design conditions for PLC application:
complete the design conditions required for PLC application software programming: PLC equipment installation and technical services;
expansion and reconstruction projects can be implemented as a reference according to the actual application situation: This regulation does not include the built-in programming software of the PLC and the internal connection of the system. 1.0.3
The relevant standards are as follows:
HG/T20505
HG/T20508
HG/T20509
HG/T20512
HG/T20513
"Functional Signs and Graphic Symbols for Process Measurement and Control Instruments""Control Room Design Regulations"
"Instrument Power Supply Design Regulations"
"Instrument Piping and Wiring Design Regulations"
"Instrument System Grounding Design Regulations"
When implementing these regulations, the requirements of the relevant national standards in force shall also be met. 417
PLC Engineering Design Procedure
Basic Design/Preliminary Design
2.1.1 Determine the Monitoring Scheme of PLC
Based on the preliminary version of the Pipeline and Instrumentation Flowchart (P&ID), the technical scheme of the control system and interlocking system, the electrical system diagram and the operating instructions completed in the basic design/preliminary design, count the number of PLC input/output points and the number of control and detection loops, and preliminarily determine the selection of PLC models and the configuration of external equipment. 2.1.2 Complete the preliminary inquiry technical specification of PLC and the preliminary inquiry work. 2.1.3 According to the preliminary technical scheme agreed with the PLC supplier, complete the system configuration diagram and control room layout diagram of PLC.
2.1.4 Submit preliminary design data to relevant disciplines According to the PLC configuration and technical requirements, submit design conditions to the structural, architectural, HVAC, electrical, fire protection, telecommunications and other disciplines: Based on the preliminary technical review of the PLC supplier's quotation, submit the design conditions of PLC investment to the budgeting discipline according to the preliminary PLC technical scheme. 2.2 Engineering Design/Construction Drawing Design
The work in the PLC engineering design phase includes external inquiry and technical review of the quotation and related meetings, engineering design, and application software programming.
2.2.2 Inquiry, quotation, review and meeting
Prepare the technical part of the "PLC Technical Specification". 1
2Conduct technical review of the quotation document of the PLC supplier. "3 Based on the technical review of several PLC supplier quotations, put forward technical review opinions, and the end user (purchasing department) determines the PLC selection and supplier. 4 Confirm with the determined PLC supplier that the contents of the PLC contract technical attachments include: hardware configuration diagram, hardware list, software list; standards and specifications adopted for PLC manufacturing, installation, and commissioning; technical service terms; programming and training arrangements and the scope of responsibility of each party; acceptance requirements; spare parts and special calibration instrument lists; project schedule, etc. 5 Participate in the PLC supplier's technical clarification meeting and design conditions meeting. The main contents include: confirming hardware specifications and 418
adjusting the scope of supply; determining the scope of work of both parties; agreeing on the content, depth, purchase varieties, delivery date, number of copies, and delivery method of the technical documents submitted by both parties and location; communication between the two parties; confirmation of the project schedule and other relevant technical issues. Signing of the PLC engineering design conditions meeting memorandum. 2.2.3
The following work should be completed during the engineering design phase: system configuration diagram (provided by the supplier);
cabinet hardware layout diagram (provided by the supplier); complex control system block diagram;
sequential control, logic control, timing control, batch control schematic diagram; control room equipment plan layout diagram;
layout and wiring diagram of various cabinets;
instrument loop diagram and I/0 list;
auxiliary instrument panel, operating table layout and wiring diagram; indoor instrument cable and wire plan layout diagram; 10power supply system diagram;
11grounding system diagram;
12PLC cabinet, operating table , auxiliary instrument panel, installation drawing of the table; 13 Propose engineering design technical conditions to relevant professionals (structure, architecture, HVAC, electrical, fire protection, telecommunications). 2.2.4
The following tasks should be completed during the application software programming phase: system configuration programming;
PLC database (including data input, debugging and modification, etc.); programming of sequential control, logic control, timing control, batch control; process flow chart screen;
PLC operation group allocation;
PLC variable display and recording screen;
PLC report;
peripheral device interface programming;
historical database programming;
10other programming.
PLC application scope
PLC application principles
3.1 .1PLC and its related equipment should be integrated and standardized, and should be selected according to the principle of being easy to form an integral whole with the industrial control system and easy to expand its functions. 3.1.2 The selected PLC must be a mature and reliable system with operational performance in the chemical industry or related industrial fields.
The system hardware, software configuration and functions of the PLC should be adapted to the scale and control requirements of the device. 3.1.3
Basic application
3.2.1PLC can form a decentralized multi-level control system and be used in control occasions of different scales. PLC is used for production control and should meet the following basic conditions: 1. The process control parameters are mainly digital, and the control system is mainly based on sequential control, logic control or electrical control (such as motor interlocking control, etc.). Industrial production equipment. 2. The process production technology is mature and the operation experience is rich, which is conducive to the engineering design and commissioning of PLC. 3. Compared with the conventional relay interlocking system and analog instrumentation, the selection of PLC in engineering design has reasonable technical and economic indicators.
Although PLC has a similar structure to DCS, it has its own characteristics in application selection compared with DCS. 3.2.2
1PLC is designed for the field, with compact design, firmness, small size, light weight and high reliability. Therefore, PLC is easy to install inside the machine or the on-site unit panel to realize mechatronics. 2PLC control system has a simple structure and strong versatility. It is divided into several major categories according to its I/O control capacity. It also has a wide variety of components, which can easily form control systems of various sizes and requirements. Its system can range from a small scale of 10 points to a large scale of 10,000 points and above. 1) From the perspective of miniaturization, it strives to be compact, low-priced, easy to operate, integrate the human-machine interface and control functions, and develop in the direction of specialization. 420
2) From the perspective of large-scale, it strives to be large-capacity, high-speed and multi-functional. Modern data communication and network technology are used to form a multi-layer distributed control system and an automation network for the entire factory, realizing open architecture and standardized communication functions, which can meet the needs of process control of large-scale joint devices. 3. There are many types of human-machine interfaces, suitable for different operating occasions. There are dedicated operator modules and operator interfaces installed on site for single tasks, and there are also industrial control computer human-machine interfaces installed in the central control room responsible for plant-wide production control operations, which can meet the different needs of on-site operations and centralized operations. 4. Strong anti-interference ability: PLC is specially designed for industrial sites, adopts multi-level anti-interference measures, can work in harsh environments, and the average failure-free time can be as high as 200,000 hours. Compared with DCS, PLC has no special requirements for the environmental conditions of its installation.
5. Fast action: PLC nodes react quickly and at high speed. The execution time of each binary instruction is 0.2~0.4us. Adapt to the needs of control occasions with high control requirements and fast response requirements. 6 Simple programming and flexible modification: PLC uses control logic language oriented to control operations, such as logic diagrams, ladder diagrams or simple instruction forms oriented to control, which is easy for programmers and on-site operators to master and apply, and easy to promote; at the same time, PLC uses programs to perform control functions, providing designers with extremely convenient means to improve and revise the original design, and can meet the requirements of frequent changes in production processes. 7 Performance-price ratio: When the device control parameters are digital or the electronic control functions are large, and the number of analog control times is relatively small, the performance-price ratio of PLC is better than that of DCS. At the same time, PLC provides convenience for solving the coordination and cooperation between sequential control, PID adjustment, and interlocking protection. With the enhancement of PLC communication capabilities, the application of PLC in process control will be a way with superior performance and price. 421
4PLC hardware configuration
4.1 Human-machine interface (operation station)
The human-machine interface used in the local operation of the on-site unit and the small-scale PLC (less than 200 digital points) system has the following types:
1Button panel: generally used in fixed electromechanical operation, installed on the unit, with all the functions of the system operation panel, and additional functions do not require PLC programming. 2Operation panel, touch screen: generally used in local unit control, with a high protection level (IP65), can be directly installed on the unit. It can also load monitoring software and programming data, with the functions of displaying process monitoring data and operating process variables, recipe management, etc.
3Portable operation monitor: used for the operator's human-machine interface, fault finding, and system debugging. It has the functions of monitoring controller status, starting/stopping controller, forced output, and modifying register values, and is suitable for application in small-scale PLC systems.
4.1.2 Generally, large and medium-sized PLCs have a large number of control points and require centralized operation and management. Therefore, an operation station (hereinafter referred to as the operation station) mainly composed of a personal computer (PC or industrial PC) or a minicomputer should be set up as needed. 4.1.3 The operation station should be equipped with software that runs and is programmed under a standard operating system, and should have a graphics system, an alarm information system, an application program interface, a variable archive, a standard communication interface, a reporting system, and a data processing system. The hardware and software of the operation station host should have high reliability, and the hardware configuration of the operation station should meet the following minimum requirements: 132-bit bus. The main frequency is above 200 MHz, a 32-bit or 64-bit central processing unit (CPU), greater than or equal to 64M random access memory (RAM), and a small computer interface (SCSI): 2 The operation station should be equipped with a hard disk drive, and should also be able to be equipped with external storage devices such as a CD-ROM drive or a tape drive;
3 All peripherals and interfaces of the operation station (software, hard disk drive, display, keyboard, mouse or ball mark, printer, etc.) should be universal.
4.1.4 The operation station shall have different levels of operation authority and operation authority for different operation areas or data sets. The operation authority is limited by passwords and keys and divided in programming for use by personnel in different positions. The configuration of the operation station shall meet the following requirements: 4.1.5
1 The operation station shall be configured according to the operation area;
2 For important sections or key equipment, a dedicated operation station shall be configured; 3 According to the needs of sequential control, batch control or logical control, the operation station or operation table shall be configured according to the division of positions, production lines, and operation units and according to their complexity. 4.1.6: The specifications of the display of the operation station should be a color cathode ray tube display (Cathode-RayTube, abbreviated as CRT) with a diagonal size greater than or equal to 47cm and a resolution higher than 1024×768. 4.1.7 For important operation areas, one operation area shall be equipped with at least two operation stations with host computers that serve as backup for each other. In general, the mutual backup of operation stations can also be in the form of mutual backup between operation stations located in different operation areas in the same control room.
4.1.8 The number of operation stations can be estimated according to the number of digital 1/0 points [analog 1/0 points can be converted into digital I/0 points, that is, 1 AI (AO) = 15 DI (DO) 1, and should meet the following requirements: 1000~1500 digital I/0 points: 2 units can be configured; 1500~3000 digital 1/0 points: 2~3 units can be configured; 3000~5000 digital 1/0 points: 3~4 units can be configured; 5000~8000 digital I/0 points: 4~6 units can be configured; 8000 digital 1/0 points and above: can be configured according to actual needs. 4.1.9 The operation station should be equipped with one alarm printer and one report printer each as backup for each other. The number of printers can be appropriately increased or decreased according to the scale of the device and actual needs. The plant-wide PLC can be equipped with one color printer or color copier (for screen copying).
4.1.10 It is not advisable to set up a recorder and backup handheld operator outside the PLC without special needs. 4.1.11 If necessary, an auxiliary operation table can be set up to install the recorder, handheld operator, alarm/light, pump, interlock and emergency stop button switches on this table. 4.2 Central Processing Unit (CPU)
4.2.1 Storage capacity: The capacity of the CPU's built-in memory (RAM) and the capacity of the expandable memory (to store user programs and data) can be selected according to the following estimation method: 1 Generally, the memory capacity can be selected according to the I/0 points that are mixed at will, that is: at least 8K memory should be selected for 256 I/0 points.
2 The memory capacity can also be selected through preliminary calculation, that is: 1) Discrete 1/0 points × 10 = instruction word
2) Analog 1/0 points × 25 = instruction word
3) Special 1/0 modules × 100 = instruction word
Total memory requirement estimate: 1) + 2) + 3) = instruction word 3 If the selected PLC system is to complete more complex control functions, it should be based on the preliminary estimation of memory capacity results, and select a larger capacity and higher grade memory to meet the realization of complex control functions. 4.2.2 According to the composition of the PLC communication network, select the CPU's local communication function and the system network communication function it supports.
4.2.3 Control capacity (1/0 capability): the number of digital 1/0 and analog I/0 points, the type, quantity and function of function blocks, and the number of software controllers (loops). 4.2.4 Scan cycle (processor scan time): 1 For small PLCs, the scan time should be less than or equal to 0.5ms/K. 2 For large and medium-sized PLCs, the scanning time should be less than or equal to 0.2ms/K. 4.2.5 Instruction functions and software support should have basic operation instructions (such as counting, calculation, data conversion, comparison, sequencer, program control and PID control and sequential function flow chart, etc.) and complete system functions (interrupt masking, diagnostic function, interrupt and signal function, etc.).
Software support should include simulation software in addition to programming software. PLC development and debugging can be completed on a computer using a standard operating system (such as WIN95/NT), shortening the development time of the application system. 4.2.6
Redundancy functionsbZxz.net
Important process unit control: CPU (including memory) and power supply should be 1:1 redundant. When necessary, you can also choose:
Hot standby redundant system composed of PLC hardware and hot standby software; hot standby CPU redundant system;
Duplex or triple redundant fault-tolerant system. The CPU load should not be less than 50%, and the maximum should not exceed 70%. 4.3 Communication network
4.3.1 Medium and large PLC systems should be able to support a variety of field buses and standard communication protocols (such as TCP/IP). When necessary, it should be able to connect to the factory management network (TCP/IP). Its communication network should comply with ISO/IEEE communication standards and should be an open communication network.
4.3.2 The communication interface of PLC should include serial and parallel communication interfaces (RS-232C/422A/423/485, etc.), RIO communication ports, industrial Ethernet (Ethernet), common DCS interfaces, etc. 4.3.3 For large and medium-sized PLC communication buses (including interface devices and cables), 1:1 redundant configuration should be adopted; its communication bus should comply with international standards: the communication distance should be able to meet the actual requirements of the device (or factory). 4.3.4
PLC control network The network communication speed of the upper level should be greater than 1Mb/s. The load of the communication bus should not exceed 60%.
Main forms of PLC network
A simple PLC network is composed of a personal computer as the master station and multiple PLCs of the same model as slave stations. A master-slave PLC network is composed of one PLC as the master station and multiple PLCs of the same model as slave stations. The PLC network is connected to a large distributed system through a specific network interface to become its subnet. Dedicated PLC network (i.e., a dedicated communication network for each PLC manufacturer). Implementation of PLC communication network
The connection between the basic frame equipped with CPU and I/O (I/0 rack or I/0 unit) has various forms depending on the control requirements. Generally, it is realized through parallel communication to connect with the local I/0 rack or remote I/0 rack: the distance between the local I/0 rack is 15~30m, and the distance to the remote I/0 rack is no more than 200m. The CPU basic rack and remote I/0 can also be connected through the field communication bus, with a distance of up to 2000m. Through the repeater connection, a longer distance connection can be achieved. This constitutes a simple PLC network structure. 2 When a more complex system network structure is formed, in order to reduce the communication task of the CPU, a communication processor with different communication functions (such as point-to-point, fieldbus, industrial Ethernet) should be selected according to the actual needs of the network composition. 3 When the system is large in scale and multiple central processors are selected in the system, when it is necessary to link the centralized expansion or distributed expansion units in the local environment radius, the receiving and sending communication interface units can be selected to realize the communication between the various communication network layers.
4.41/0 interface unit
The technical specifications of various I/0 interface units must match the field signal source or load. The redundancy of the I/0 interface shall comply with the following provisions: The multi-point input/output (1/0) card of the control loop should be redundantly configured. The multi-point input/output (I/O) card of the important detection point can be redundantly configured. According to the needs, for important 1/0 signals, dual or triple 1/0 interface units can be selected. The spare points of 1/0 interface shall meet the following requirements: The spare points of various control points and detection points shall be 20%~30% of the actual design points. The spare space of 1/0 card slot (position) is 15%~20%, and 15%~20% spare terminals are available. 4.4.4
For detection points far away from the central control room, it is advisable to use decentralized remote 1/0 units or remote I/0 frames. 425
4.4.5 The setting of process interface related equipment shall meet the following requirements: 1 When the signal source comes from or is sent to the explosion-hazardous area, and intrinsic safety explosion-proof measures are adopted in accordance with explosion-proof requirements, a safety barrier shall be set on the field side of the I/0 interface. 2 When the capacity of the switch quantity interface cannot meet the load requirements or the switch quantity needs to be isolated, a relay shall be set.
The parameters of the transmitter, safety barrier, various converters and isolators must match the PLC. 4.5 Programming terminal and engineer station
PLC programming terminal should be selected according to the following principles: Small fixed PLC can choose handheld programmer. 1
For PLC with small system scale, handheld programmer can be selected with programming memory block. 2
3For large and medium-sized PIC, the programming software package provided by the manufacturer should be selected, and equipped with a personal computer (PC or industrial PC) with technical indicators that can ensure the operation of the programming software package. The programming terminal should have the following functions: 1) It can be used as an operation station at the same time;
Provide a software package compatible with a personal computer: compile the running program of the PLC
Programming can be done online or offline: 5
It can realize offline or online debugging of the PLC. 4.5.2
Engineer station
Configure the engineer station according to the needs of PLC configuration: PLC used in the whole plant or large equipment should be equipped with an engineer station; the engineer station can be equipped with auxiliary equipment such as laser printers. 4.6 Communication interface and application computer
For large-scale devices and combined devices, the corresponding network interface can be configured according to the needs of factory management. 4.6.2
PLC should have a communication interface for connecting to a common distributed control system (DCS). Configure the application computer according to the needs of the control software. 5.1.1
PLC software configuration
System software
PLC should be equipped with a standardized general operating system. The system software should be open software. General database management software, high-level language and other tool software should be equipped as needed. Computer interface or network interface software should be equipped according to the configuration and needs of the hardware equipment. 5.2 Process control and operation software
PLC must be equipped with complete process control and detection software. PLC must be equipped with complete process operation and data processing software. It should be equipped with complete batch control, sequential control, complex control and other software as needed. 5.3 Standardized Programming Languages
PLC standardized programming languages have five types
Three graphical languages:
Sequential Function Chart (SFC)
Ladder Diagram (LD)
3) Function Block Diagram (FBD)
Two textual languages:
Instruction List (IL)
Structured Text (ST)
PLC system should be able to run several or all of the above programming languages and comply with their standards (IEC1131~3). At the same time, PLC system should also support multiple language programming forms, such as C, BASIC, etc., to meet the control needs of special control occasions.2
Engineer station
Configure the engineer station according to the needs of PLC configuration: PLCs used in the whole plant or large-scale devices should be equipped with engineer stations; the engineer station can be equipped with auxiliary equipment such as laser printers. 4.6 Communication interface and application computer
For large-scale devices and combined devices, the corresponding network interface can be configured according to the needs of factory management. 4.6.2
PLC should have a communication interface for connecting to a common distributed control system (DCS). Configure the application computer according to the needs of the control software. 5.1.1
PLC software configuration
System software
PLC should be equipped with a standardized general operating system. The system software should be open software. It should be equipped with general database management software, high-level language and other tool software as needed. It should be equipped with computer interface or network interface software according to the configuration and needs of hardware equipment. 5.2 Process control and operation software
PLC must be equipped with complete process control and detection software. PLC must be equipped with complete process operation and data processing software. It should be equipped with complete batch control, sequential control, complex control and other software as needed. 5.3 Standardized Programming Languages
PLC has five standardized programming languages
Three graphical languages:
Sequential Function Chart (SFC)
Ladder Diagram (LD)
3) Function Block Diagram (FBD)
Two textual languages:
Instruction List (IL)
Structured Text (ST)
PLC system should be able to run several or all of the above programming languages and comply with their standards (IEC1131~3). At the same time, PLC system should also support multiple language programming forms, such as C, BASIC, etc., to meet the control needs of special control occasions.2
Engineer station
Configure the engineer station according to the needs of PLC configuration: PLCs used in the whole plant or large-scale devices should be equipped with engineer stations; the engineer station can be equipped with auxiliary equipment such as laser printers. 4.6 Communication interface and application computer
For large-scale devices and combined devices, the corresponding network interface can be configured according to the needs of factory management. 4.6.2
PLC should have a communication interface for connecting to a common distributed control system (DCS). Configure the application computer according to the needs of the control software. 5.1.1
PLC software configuration
System software
PLC should be equipped with a standardized general operating system. The system software should be open software. It should be equipped with general database management software, high-level language and other tool software as needed. It should be equipped with computer interface or network interface software according to the configuration and needs of hardware equipment. 5.2 Process control and operation software
PLC must be equipped with complete process control and detection software. PLC must be equipped with complete process operation and data processing software. It should be equipped with complete batch control, sequential control, complex control and other software as needed. 5.3 Standardized Programming Languages
PLC has five standardized programming languages
Three graphical languages:
Sequential Function Chart (SFC)
Ladder Diagram (LD)
3) Function Block Diagram (FBD)
Two textual languages:
Instruction List (IL)
Structured Text (ST)
PLC system should be able to run several or all of the above programming languages and comply with their standards (IEC1131~3). At the same time, PLC system should also support multiple language programming forms, such as C, BASIC, etc., to meet the control needs of special control occasions.
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