Allen-Bradley 1757-FFLD2, User Manual

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Rockwell Automation Publication 1757-UM012A-EN-P - July 2011 11
Chapter
1
FOUNDATION Fieldbus System
Introduction This section explains the components of a typical FOUNDATION Fieldbus
system and the integral roles that RSFieldbus configuration software and the
Rockwell Automation linking devices (catalog numbers 1757-FFLD and 1757-
FFLDC) contribute to process control.
Through the FOUNDATION Fieldbus protocol, the 1757-FFLD and
1757-FFLDC linking devices provide connectivity for fieldbus devices to Logix
controllers, such as ControlLogix and CompactLogix. The linking devices bridge
RSFieldbus host to Fieldbus Foundation H1 segments for high-speed
transmission of process data.
The 1757-FFLD linking device connects H1 segments to Fieldbus Foundation’s
High-speed Ethernet (HSE) running over the EtherNet/IP network. The
1757-FFLDC linking device bridges from the ControlNet network to fieldbus
devices on H1 segments.
Both linking devices can have either two or four H1 segments, with each segment
supporting the recommended maximum 8…10 devices, and a maximum of 64
publisher and 64 subscriber VCR connections.
Fieldbus Standards
The term fieldbus refers to an all-digital, two-way communication system that
connects control systems to instrumentation.
The Fieldbus Foundation organization developed the F
OUNDATION
Fieldbus
protocol to create a fieldbus network based on the principles of the ISA and IEC
standards (ISA S50.0 and IEC61158). Today, this protocol is widely accepted as
the standard for pure digital communication with ‘smart’ (microprocessor-based)
field devices. Devices connected by a F
OUNDATION
Fieldbus network are used
for sophisticated, highly-distributed process control.
F
OUNDATION
Fieldbus technology has been integrated into the PlantPAx
Process Automation System based on Rockwell Automation’s Integrated
Architecture through Fieldbus Foundation linking devices (catalog numbers
1757-FFLD and 1757-FFLDC).