Rockwell Automation PLC-5 Fieldbus Solutions for Integrated Architecture User Manual - Manual (Page 42)

Publication 1757-UM006A-EN-P - May 2002
1-28 The Fieldbus Communication Model
Device Description infrastructure
The Fieldbus Foundation defines a four-level infrastructure for Device
Descriptions for the sake of consistency. See Figure 1.14 for a
graphical representation of the DD infrastructure.
Figure 1.14 Device Descriptions infrastructure.
Levels 1, 2, and 3 are the Device Descriptions that the Fieldbus
Foundation provides on CD-ROM.
Level 1 consists of Universal Parameters that define common
attributes such as Tag, Revision, and Mode. All blocks must include
Universal Parameters.
Level 2 consists of Function Block Parameters that define parameters
for all standard Function Blocks including the standard Resource
Block.
Level 3 consists of Transducer Block Parameters that define
parameters for the standard Transducer block. In some cases, the
Transducer Block specification may add parameters to the standard
Resource Block.
Level 4 is the Manufacturer Specific Parameters that define the
parameters a manufacturer has added to the standard Function Block
and Transducer Block parameters. These added parameters will be
included on the manufacturer's Incremental DD.
RESOURCE
TEMP FLOW
AI PID
Resource
Block
Transducer
Block
Function
Block
Level 1:
Universal
Parameters
Level 2:
Function
Block
Parameters
Level 3:
Transducer
Block
Parameters
Level 4:
Manufacturer
Specific
Parameters
Defined by
Fieldbus Foundation
Specification
Defined by
Manufacturer