10. Appendix A
10.1. Fieldbus Technology
378 Experion PKS Series A Fieldbus Interface Module User's Guide R400
Honeywell July 2010
Communication layer description
The following table provides a summarized description of the communication layers that
make up the F
OUNDATION Fieldbus. The Fieldbus Foundation maintains a complete
library of detailed reference specifications including a Technical Overview and Wiring
and Installation Guides.
REFERENCE - INTERNAL
Please refer to
Fieldbus network references for a list of available documents or visit the
Fieldbus Foundation web site
http://www.fieldbus.org/ for additional details
and ordering data.
Layer Functional Description Associated Terms
Physical
Defines the transmission medium for fieldbus
signals and the message conversion tasks
to/from the Communication Stack.
Based on the Manchester Biphase-L Encoding
technique, so a F
OUNDATION Fieldbus (FF)
device interprets a positive transition in the
middle of a bit time as logical "0" and a
negative transition as logical "1".
Complies with existing International
Electrotechnical Commission (IEC 1158-2) and
the Instrumentation, Systems, and Automation
Society (ISA S50.02) physical layer standards.
And, it can be used with existing 4 to 20mA
wiring.
H1, 31.25 kbit/s
signal rate
H1 Link
H1 Segment
HSE, High Speed
Ethernet
Data Link (DLL)
Defines how messages are transmitted on a
multi-drop network. It uses a deterministic
centralized bus scheduler called a Link Active
Scheduler (LAS) to manage access to the
fieldbus. It controls scheduled and unscheduled
communications on the fieldbus in a
publish/subscribe environment.
Identifies device types as Basic Device, Link
Master, or Bridge. A Link Master device type
can become a Link Active Scheduler (LAS) for
the network.
Compel Data (CD)
message
Pass Token (PT)
message
Time Distribution
(TD) message
Live List
Link Active Scheduler
(LAS)
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