An Improved Model for OD and Object Description in Fieldbus Intelligent Instruments Based on Object-Oriented Design

Abstract:

At present, objects dictionary (OD) and object descriptions used in fieldbus intelligent instruments are based on variable-sized storage and constant property values, which constrains the flexibility and portability in data access and modularization and encapsulation in system design. In this paper, a kind of universal data structure for object description in OD was presented. Universal management of object description with different types could be realized with the proposed structure. Based on principle and methodology of Object-Oriented Design (OOD), an improved model for object description was proposed. In the improved model, constant value used in object code field of object description is replaced by function pointer pointing to object instance handler for data process of object instances belonging to the same class. Universal function structure is used for all class object instance handlers for different classes but instances belonging to different classes are manipulated differently with their own handlers. The improved model for OD and object description was proven effective and efficient by the practice of development and design of intelligent instruments in distributed control network.

• Periodical: Key Engineering Materials (Volumes 439-440)
• Pages: 635-640
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.439-440.635
• Online since: June 2010
• Authors: Geng Liang, Wen Li, Yan Bai
• Keywords: Fieldbus, Function Pointer, Object Description, Object Dictionary, OOD

References

[1] Foundation TM Specifications Function Block Application Process Part1 FF2890 FS114. Fieldbus Foundation , (1999).

[2] Foundation TM Specifications Function Block Application Process Part2 FF2891 FS114. Fieldbus Foundation , (1999).

[3] Foundation TM Specifications Fieldbus Message Specification FF2870 FS115. Fieldbus Foundation , (2001).

[4] Foundation TM Specifications System Architecture , FF2581FS111 . Fieldbus Foundation , (2000).

[5] N.P. Mahlik. Fieldbus Technology, Springer-Verlag, Berlin, (2003).

[6] X.H. Yang. Fieldbus Technology with Application，Tsinghua University Press, Beijing，(1999).

[7] GX Chen, DQ Feng, J Chu. Principle and Realization of Instantiation of Foundation Fieldbus Function Block，Process Automation Instrumentation，27(5): 1-4，(2006).

[8] ZJ Yang, Y Lin. Technical Means of Interoperable Foundation Fieldbus, CONTROL & AUTOMATION, 14(3): 4-7, (1998).

[9] CJ Liu, DQ Feng. HSE Analysis on the establishment of the link between objects in function block application process of foundation fieldbus based on high speed Ethernet, Industrial Instrumentation & Automation, (1): 3-6, (2005).

[10] Zhongfeng Wang; Haibin Yu. The research of XML-based extensible device description for FF fieldbus system; Industrial Electronics Society, 2004. IECON 2004. 30th Annual Conference of IEEE，Volume 3, 2-6 Nov. 2004 Page(s): 2600 - 2603 Vol. 3.

DOI: 10.1109/iecon.2004.1432213

[11] J Liu, DQ Feng. The Device Description Technology Based XML, Industrial Control Computer，16（11）: 32-34, (2003).

[12] K Zhao, YB Pang. Research on Interoperability of Fieldbus Equipment Based on XML, Process Automation Instrumentation, 26（4）: 10-13, (2005).