Wang Wen-hai

Design of Real Time Control Software Based On QNX

System architecture of one real time control software is given in this article, and the design method is introduced for each module. The real time control software support the redundant of system network, control network and control station, enhance the robustness of system greatly; select QNX as real time operation system, support control algorithm editor based on IEC61131-3, and tasks with different period or stimulate by event all supported in this software; receive operate instruction and unload real time value through Ethernet by socket; in the handle program of interrupt from CAN, acquisition of real time data from 32 IO board can be finished in 320 ms. This real time control software has been used in one DCS system, and has strong robustness and high real time ability

On soft fault diagnosis method based HHT for analog circuits

To diagnose soft fault for analog circuits, a method based on Hilbert-Huang Transform (HHT) is established. Through applying an alternating signal to the circuit under test and the output point as the sole test point, HHT processes output voltage signal, energy of intrinsic mode function (IMF) components and Hilbert marginal spectrum composed of fault feature vector. The fault components can be localized combined with BP neural network. This method can not only diagnose single fault, but also diagnose multiple faults. The simulation experimental results demonstrate that the average single fault diagnosis rate is 96% and the average multiple faults diagnosis rate is 91.3%, the actual experimental results demonstrate that the average fault diagnosis rate is 82%, verify the effectiveness and practicality of the proposed approach.

VM & process control system

The purpose of the virtual manufacturing (VM) concept is to integrate existing manufacturing models, techniques of analysis and forms of representation in a consistent system in such a way that concurrent engineering within the planning of a new product or manufacturing system can be accomplished. In this paper, the VM concept in process control is put forward. Then, on the basis of the concept of process control, the DCS and the VM concept, an environment of an industrial control computer system including model creation, control, optimization and simulation is set up. For the example and testing of the VME for process control, the simulation system for a pulp and paper mill is established. The result of the simulation is satisfactory.