This Part 3 of the standard specifies the requirements for the overall functionality and engineering services to
achieve building automation and control systems. It defines terms, which shall be used for specifications and it
gives guidelines for the functional documentation of project/application specific systems. It provides a sample
template for documentation of plant/application specific functions, called BACS points list in annex A.
The informative function block examples explain a method to display the referenced functions in system
documentation; they do not standardize the method for programming functions and applications.
This part of the standard covers the following:
Requirements and definitions regarding BACS and application software, generic functions for plant/project specific
applications and engineering functions for building controls and operations. It provides communication functions
for the integration of other dedicated special system processes. The functional requirements in this part of the
standard are subdivided as follows:
~t-- System management and application software:
describes the requirements for plant independent systems and human system interface programs related to a
project, including the operating system. This standard does not dedicate the following system functionality to any
particular hardware, e.g.:
-- system diagnostics, watchdog, redundancy, time keeping, access control, log lists;
-- point identification, event message handling, print control;
-- database, statistics, data archiving, remote access;
-- system communications.
-- Human system interface (HSI), point information presentation, graphics, alarms, time scheduling.
-- Engineering process and tool software:
describes the requirements for configuring of the hardware and control strategies, the system management and
the commissioning process.
~-- BACS application processing programs and plant/application specific functions:
describes the requirements for plant, application and/or project specific functions and a method for the
documentation of a project. The functions are subdivided into the following types:
-- input and output functions, physical and shared;
-- processing functions (e.g. for monitoring, interlocks, control and optimization);
-- management functions (system programs), and required communications;
-- operator functions.
This Part 3 defines a method for specifying the procurement specifications containing all essential elements required
for the operational functioning of a BACS. The successful installation and operation of a BACS requires that its
procurement be based on a complete and accurate functional specification.
The standard provides a template called the 'BACS points list' that can be found in annex A (normative). Its purpose is
to determine and document the options for plant/application specific functionality based on the plant/control schematic.
Further explanations can be given in form of plant/control descriptions and control flow chart diagrams. Examples are given in annex B (informative). The exact specifications will be project-specific. Information about the standardized
functions is given in the form of informative examples as function-blocks, textual, and graphical descriptions in 5.5.
It is recognized, that functions can be described and implemented in many different ways, depending on:
-- climatic differences:
-- cultural and regional differences;
-- national regulations.