Rockwell Automation PLC-5 Fieldbus Solutions for Integrated Architecture User Manual - Manual (Page 19)

Publication 1757-UM006A-EN-P - May 2002
The Fieldbus Communication Model 1-5
Figure 1.2 Function Block Application Process based on blocks
User
Application or
Function Block
Application
Process (FBAP) Defines blocks to represent different types of application functions. The three types of
blocks are the Resource block, the Function block, and the Transducer block. See
Figure 1.2.
The Resource block is used to describe characteristics of the fieldbus device such as the
device name, manufacturer, and serial number. Each fieldbus device requires one
Resource block.
The Function block is used to define the specific characteristics of the process control
function. The Fieldbus Foundation provides a set of pre-defined function blocks. A single
fieldbus device can include many Function blocks to achieve the desired control
functionality. See the following section, Standard Function Blocks for more information.
The Transducer block is used to interface Function blocks with local input/output
devices. They read sensors and command outputs, and contain information such as
calibration date and sensor type. One Transducer block is usually included for each input
or output Function block.
These associated objects are also defined in the User Application: Link Objects, Trend
Objects, Alert Objects, and View Objects. They provide linking between internal Function
block inputs and outputs, trending of Function block parameters, reporting of alarms and
events, viewing of predefined block parameter sets through one of four defined views.
The four defined views are View 1 - Operation Dynamic, View 2 - Operation Static, View
3 - All Dynamic, and View 4 - Other Static. Resource block
Function block
Transducer block
Link Objects
Trend Objects
Alert Objects
View Objects
View 1 - Operation Dynamic
View 2 - Operation Static
View 3 - All Dynamic
View 4 - Other Static
Table 1.A Communication Layer Descriptions
Layer Functional Description Associated Terms
Physical Layer
Communication
Stack
User Application
Resource
Block
Function
Block
Transducer
Block
Fieldbus
Fieldbus Foundation
Defined Blocks