Design and Implementation for Ladder Diagram in Hydropower Simulation System Based on All Paths Searching Algorithm

Bo LI, Hai ZHAO, Chun-He SONG, Hui LI, Jun AI

College of Information Science and Engineering, Northeastern University, Shenyang, China.

DOI: 10.4236/ijcns.2009.24034                

Abstract

An approach to design and implement the control function of LD (Ladder Diagram) in the hydropower simulation system based on all paths searching algorithm is proposed in this paper. LD is widely used as a programming language for PLC (Programmable Logic Controller), but it doesn’t be executed automatically in the hydropower simulation system which is a software system, and there is no compiler or interpretation for LD in it. The approach in this paper is not only to present a graphical interface to design LD, but also implement its control function through transforming it to a corresponding undigraph, in which, all paths be-tween two vertexes (live wire and null line) are searched by the proposed algorithm. An application example is presented to verify the validity of the algorithm and shows that the algorithm is correct and practicable. In addition, how to implement the control function based on object-oriented thought is introduced. The running time is shown at last, which proves that the system with the algorithm can meet the real-time request in the hydropower simulation system.

Keywords

Ladder Diagram, Object-oriented Thought, Undigraph

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	P. Sanderson, W. B. L. Wong, S. Choudhury, and R. Memisevic, “Hydro scheme control in a deregulated environment: Cognitive work models and design implications,” Annual Meeting of the Human Factors and Ergo-nomics Society, Santa Monica, CA, 2003.
[2]	J. R. Hajdukiewicz and K. J. Vicente, “What does computer- mediated control of a thermal-hydraulic system have to do with moving your jaw to speak?” Ecological Psychology, Vol. 16, No. 4, pp. 255-285, 2004.
[3]	R. Memisevic, P. Sanderson, S. Choudhury, and W. Wong, “A low-cost, easy-to-use, realtime power system simulator,” in Proceedings of International Conference on Power and Energy Systems, Clearwater Beach, FL, 2004.
[4]	Y. Su, H. Zhao, W. J. Su, and Y. Xu, “GHS: Research and application of grid based hydroelectrical simulation system platform,” Journal of System Simulation, Vol. 17, No. 5, pp. 1230-1233, 2004.
[5]	E, R. R. Kato, O. Morandin Jr., P. R. Politano, and H. A.Camargo, “A modular modeling approach for CNC machines control using Petri nets,” in Proceedings of International Conference on Systems, Man and Cybernetics, Nashville, TN, Vol. 5, pp. 3417-3152, 2000.
[6]	J.-L. Chirn and D. C. Mcfarlane, “Petri net based design of ladder logic diagram,” Working paper, Institute for manufacturing, University of Cambridge, UK, 2000.
[7]	H. S. Kim, W. H. Kwon, and N. Chang, “A translation method for ladder diagram with application to a manufacturing process,” in Proceedings of International Conference on Robotics and Automation, Vol. 1, pp. 793-798, 1999.
[8]	X. L. Cui and Z. C. Zhou, “The algorithm of transformation between the ladder language and the sentence table language of PLC,” Microelectronics and Computer, China, Vol. 1, No. 17, pp. 26-30, 2000.