
R400
Experion PKS Series A Fieldbus Interface Module User's Guide
377
July 2010
Honeywell
10. Appendix A
10.1 Fieldbus Technology
Open communications architecture
F
OUNDATION
Fieldbus is an enabling technology for dynamically integrating dedicated
field devices with digitally based control systems. It defines how all "smart" field devices
are to communicate with other devices in the control network. The technology is based
upon the International Standards Organization's Open System Interconnection (OSI)
model for layered communications.
As shown in the following figure, OSI layer 1 is the Physical Layer, OSI layer 2 is the
Data Link Layer, and OSI layer 7 is the application layer or the Fieldbus Message
Specification. A Fieldbus Access Sublayer maps the Fieldbus Message Specification onto
the Data Link Layer. Fieldbus does not use OSI layers 3 to 6, and layers 2 and 7 form the
Communication Stack. Also, the OSI model does not define a User Application, but the
Fieldbus Foundation does.
Physical Layer
Data Link Layer
Data Link Layer
Network Layer
Transport Layer
Session Layer
Presentation Layer
Application Layer
Fieldbus Message
Specification
Fieldbus Access
Sublayer
6
5
4
3
2
1
7
Physical Layer
Physical Layer
Communication
Stack
OSI Model
Fieldbus Model
User Application
User Application
Figure 36 OSI versus Fieldbus communication model.
Содержание Experion PKS Series A
Страница 241: ...5 Configuration 5 9 Summary R400 Experion PKS Series A Fieldbus Interface Module User s Guide 241 July 2010 Honeywell ...
Страница 242: ......
Страница 559: ......
Страница 560: ...Honeywell Process Solutions 1860 W Rose Garden Lane Phoenix AZ 85027 USA ...