(3) develop in the direction of industrial control software are advanced control is widely used all kinds of advanced control and optimization technology is the most effective mining and promote DCS comprehensive performance, the most direct, the most valuable development direction, including advanced control, process optimization, information integration and system integration and software development and industrialization of USES. In the future, industrial control software will also continue to standardization, network and intelligent development direction and open.
(4) the system architecture to develop in the direction of FCS purely in terms of technology, the fieldbus intergrated in DCS can have three ways: (1) field bus on the DCS system I/O bus integration - through a field bus interface card hanging on the I/O bus of DCS, fieldbus in DCS controller saw to the information as card from a traditional DCS device. Such as Fisher - Rosemount company launched the DeltaV system is the integration solutions. (2) field bus network layer on the DCS system integration -- is on the higher DCS layer network integrated fieldbus system, the integrated method of DCS control station does not need to change, the original system. Such as Smar 302 series fieldbus products can be realized in DCS system has the function of network layer integrated the fieldbus. (3) field bus through the gateway parallel integrated with the DCS system, field bus and DCS can also be achieved by gateway bridge parallel integration. Such as SUPCON fieldbus system, the use of HART protocol Bridges connecting the system operation station and field instruments, so as to realize fieldbus devices management system operation station and the HART protocol of communication between the field instruments.
Has always been the focus of the DCS is to control, it with "scattered" as keywords. But more a holistic systems focus on development of modern information integrated management, "integrated" again in the future will become the key words, to achieve control system, running system, planning system, the management system of integrated automation direction development, implementation, up from the bottom of the real-time control and optimization control of production scheduling, management, and at the highest level of strategic decision, forming a flexible, highly automated control system integration.
Hardware structure
Inspect the hierarchical structure of the DCS, DCS level and control management level is of the two most basic link of DCS.
The implementation of the process control level signal input, transformation, decentralized control functions such as operations and output. In different DCS process control level of the control device for each are not identical, such as process control unit, field control station, interface unit, and so on, but the structure of them is roughly same, FCU can collectively known as the control unit. Process management level by the engineer station, operator station, management, computer and so on, complete the centralized monitoring and management of process control level, often referred to as operating station. DCS hardware and software, are in accordance with the modular structure design, so the development of DCS is actually to the system to provide all kinds of basic module according to the actual need to become a system, this process is known as the configuration of the system.
Fold the scene control unit
Field control unit away from the control center, generally installed in the near field, its highly modular structure can be according to the needs of process monitoring and control configuration into ranged from several to hundreds of point to point the scale of point to point the process of the control unit.
Field structure of the control unit is composed of many functions dispersed board (or card) according to certain logical or physical sequence is installed on board box, each site between control unit and control management level is USES the bus connection, in order to realize the information interaction.
Field control unit of the hardware configuration need to complete the following content:
Plug-in configuration according to the requirement of the system configuration and control scale host plug-in plug-in (CPU), power supply plug-in, such as I/O, communication plugin hardware equipment;
Hardware redundancy configuration of key equipment redundant configuration is an important means to enhance the reliability of DCS, the DCS can usually to the host, power supply plugin, communication and network, the key I/O plugin can realize redundant configuration.
Different DCS hardware installation, for all kinds of plug-ins in the plug-in installed in the box, the logical order or the physical sequence has the corresponding provisions. In addition, the control unit is usually divided into basic and extended type two kinds, the so-called basic is a variety of plug-in installed in a plug-in box, but more should be extensible structure form, that is, a field control unit includes a number of digital input/output expansion unit, become an organic whole repeatedly with bus between each other.
In terms of nature, the structure of the control unit and the configuration requirements and modular PLC hardware configuration is the same.
Software system operation station
The operation station to complete in the DCS system development, produce, test and run the task, which requires corresponding support system software, the software includes operating systems, programming languages, and all kinds of tools, etc. A perfect set of DCS, applications running on the operating site should be able to achieve the following functions: real-time database, network management, history database management, graph management, historical data trend display and modification, detailed record management, database report generation and printing, man-machine interface control, the control circuit, parameter lists, serial communication, and a variety of configuration, etc.
The configuration of folding edit this paragraph
Development and generate DCS configuration ()
The development process of DCS system configuration software based on the control system is mainly the process of the actual need to generate all kinds of application software. Configuration software functions include basic configuration the configuration and application software configuration. Basic configuration configuration is a configuration information to the system, such as system of the number of station, their index sign, each control station, the maximum points, the shortest execution cycles and memory capacity, etc. The configuration application software included more rich content, mainly including the following respects.
Fold control circuit configuration
Configuration of control circuit, in essence is to use the system to provide all kinds of basic functional modules, to form a variety of practical control system. Various DCS provide the configuration method of each are not identical, induces a specified operation module connection way, way of decision table, steps records and so on.
Arithmetic module connection way is by calling various independent standard operation module, with lines connected into a variety of control circuit, automatic generation control software, finally this is a kind of information flow and control functions are very intuitive configuration method. Decision table method is a pure form of form, as long as according to the requirements of the configuration forms, item by item, fill in the content or answer questions, this approach is conducive to the user's configuration operation. Step into way is a way of writing based on language instruction, programming much freedom, all sorts of complicated functions can be fixed by some skills, but the configuration efficiency is low. In addition, because of this configuration method is not intuitive, often for configuration engineers in the technical level and configuration experience have higher requirements.
Fold the real-time database is generated
Real-time database is the DCS is the most basic information resources, the real-time data from real-time database storage and management. In DCS, set up and modify real-time database records there are many methods, commonly used method is to use the universal database tool software to generate the database files, manage system directly using the data format or use some way will generate the data files can be converted into DCS the required format.
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