Decentralized control system for layering controller

Abstract

The invention relates to a decentralized control system for layering a controller. The traditional controller arranged in a plane layout manner is divided into a plurality of layers to ensure that a plurality of tasks completed by one control unit set in an original DSC (Decentralized Control System) are respectively executed by a plurality of FCUs after the function is subdivided and coordinatedby using an MCU (Microprogrammed Control Unit), thus the correspondence of the control unit and equipment is more clear, the load factor of data transmission on a backbone network is effectively reduced, the control risk is dispersed and the response speed is increased. Because the FCUs controlled in device level are placed at a site of an equipment side, the length of a cable connecting the siteequipment is reduced, and the function of realizing PID (Proportion Integration Differentiation) regulation is realized in stead of the traditional intelligent apparatus; and the site equipment is always measured by adopting conventional apparatuses. According to the invention, industrial Ethernet transmission is adopted in longer distance between the site FCUs and the MCU in a control chamber, compared with the original DCS with same control scale and distance, the control cable cost can be saved by above 60 percent, the investment cost of the site equipment is lowered, the area of the control chamber is effectively reduced, and the cost is greatly decreased.

Description

Technical field [0001] The present invention relates to an automatic control system, in particular to a distributed control system with hierarchical controllers used in the process industry. Background technique [0002] At present, the most commonly used conventional process industrial control is such as figure 1 The distributed control system shown (hereinafter referred to as the DCS system) generally includes HMI (human-machine interface, that is, operator station, engineer station, etc.), DPU (digital processing unit) and I / O parts (input and output units). The I / O components are also connected to field equipment through signal cables, and the data collected from conventional instruments or detection devices installed on the equipment are sent to the DPU. [0003] As a key component in the DCS system, DPU sends data to the HMI layer, enabling technicians to perform real-time monitoring through the operator station, or further through the engineer station to set and modify the...

AI Technical Summary

Problems solved by technology

[0007] 1. The instruments and detection devices with self-contained adjustment and digital communication functions used in the FCS system are expensive, so the total cost of the control system has not decreased. According to the existing literature, the cost has increased

[0008] 2. At present, the bus does not support redundant functions. A large number of instruments are connected to a field bus. If any bus fails, it will affect the operation of the entire system and reduce the reliability of the FCS system.

[0009] 3. In some occasions, FCS cannot provide the existing control functions of DCS

Due to the limitation of software and hardware level, the functions of its function blocks are not very strong, and the varieties are not complete enough; field instruments can only be used to form general control loops such as single loop, cascade, proportional control, etc. For complex and advanced The control algorithm cannot be implemented in the instrument yet, and there is no good solution for the situation of multiple inputs and multiple outputs in a single loop

[0010] Therefore, although the concept of fieldbus has been proposed for more than ten years, the above reasons limit the application of FCS system in the field of process control.

[0011] In addition, in the existing DCS and FCS systems, the DPUs are all arranged in a single-layer plane: taking the control of a boiler in a thermal power plant as an example, several pairs of DPUs are used to control the boiler, and each pair of DPUs needs to control multiple boilers at the same time. Auxiliary equipment; In addition, several pairs of DPUs are used to control the auxiliary equipment on the steam turbine side, that is, the functions and functions of all DPUs are in the same position. At the same time, the functional design layout of the DPU is not clearly divided, and the control efficiency is low; If the DPU fails, it will affect the operation of multiple devices and cause serious consequences for the entire system out of control.

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