Decentralized control system for layering controller

Abstract

A distribution control system with layered controllers includes a plurality of layer control units, with each of them monitoring a plurality of function groups of controlled devices divided by function or process respectively, wherein each function group of controlled devices includes a plurality of controlled devices cooperating with each other with the control parameters thereof associated with each other, and a plurality of subsidiary controlled devices at a lower level are provided under each controlled device. The layer control unit includes a plurality of main control units (MCU) and a plurality of field control units (FCU). Each of the main control units is connected to a plurality of field control units via a sub-network. The layered distribution control system clarifies the correlation between the control units and the controlled devices, thereby effectively reducing the data transfer load rate over the backbone network, distributing the control risk, and increasing the response speed.

Description

technical field [0001] The invention relates to an automatic control system, in particular to a controller layered distributed control system used in process industry. Background technique [0002] Currently, the most commonly used industrial controls for routine processes are such as figure 1 The distributed control system (hereinafter referred to as DCS system) shown generally includes HMI (human-machine interface, operator station, engineer station, etc.), DPU (digital processing unit) and I / O component (input and output unit). The I / O components are also connected to field devices through signal cables, and transmit the data collected from conventional instruments or detection devices installed on the devices to the DPU. [0003] As a key component in the DCS system, the DPU sends data to the HMI layer, enabling technicians to monitor in real time through the operator station, or to further set and modify control parameters through the engineer station; then the DPU a...

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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