International Electrotechnical Commission

Function blocks (FB) for process control   Part 1: Overview of system aspects - Edition 1.0; Replaces  PAS 61804-1
 N TS 61804-1

Annotation

This part of IEC 61804 is a Technical Specification which provides guidelines for suppliers to meet evolving requirements for digital process control systems through which users can be assured of the compatibility, the interworkability, the interconnectability, the interoperability and the interchangeability of the devices they choose. This part gives the overall requirements. For better understanding, this part gives background information and examples in annexes.

This Technical Specification defines the requirements for FBs to provide control and to facilitate maintenance and technical management as applications which interact with actuators and measurement devices:

• control covers functions necessary to bring and hold the process at the desired behaviour;

• maintenance covers functions to acquire information about the state of the process equipment and the state of automation devices including their adjustments, for example, calibrate a sensor that has drifted;

• technical management deals with information for the optimization of the process.

It is concerned primarily with the economics of the process and plant equipment. This relates in particular to the evaluation of performance and reliability of specific items of plant or equipment for all the installed period and comparison of performance and reliability of items from different suppliers performing an identical function in the same operating environment. An example of performance is the number of cycles achieved before failure of two valves from different suppliers. This allows for the production of detailed and valid statistical analysis to support management decisions and plant equipment modifications.