	US 7,478,406 B2
	Data access method for a control system
Thomas Pauly, Västerås (Sweden); Mikael Rudin, Västerås (Sweden); and Johan Andersson, Västerås (Sweden)
Assigned to ABB AB, Västerås (Sweden)
Appl. No. 10/491,282 PCT Filed Sep. 18, 2002, PCT No. PCT/SE02/01699 § 371(c)(1), (2), (4) Date Oct. 04, 2004, PCT Pub. No. WO03/032233, PCT Pub. Date Apr. 17, 2003.
Claims priority of application No. 0103345 (SE), filed on Oct. 05, 2001.
Prior Publication US 2005/0033802 A1, Feb. 10, 2005
Int. Cl. G06F 3/00 (2006.01); G06F 9/44 (2006.01); G06F 9/46 (2006.01); G06F 13/00 (2006.01)

U.S. Cl. 719—319 [719/313; 709/219; 709/238]

24 Claims

1. A method for providing access to a data item in a computer based control system for industrial process or manufacturing control, said control system including client applications and a plurality of objects and at least two access servers, wherein said objects represent various entities that have a defined functional meaning in the control system and at least one object has at least one data item associated with it, and wherein each access server provides access to at least one real-time, historical, or alarm or event data item, the method comprising:

providing an Access Service Handler component;

associating the Access Service Handler component to a client application;

sending a request for access to a data item from the client application to the Access Service Handler;

identifying with the Access Service Handler an access server that provides access to said data item by querying an object to which said data item is associated for a reference associated with said data item;

sending an access request from the Access Service Handler to the identified access server;

receiving with the Access Service Handler a response from the identified access server, the response including one or more values dependent on the data item requested;

receiving with the client application from the Access Service Handler the response; and

supervising or controlling with the client application a function in the computer controlled process or manufacturing control system utilizing the one or more values.