Rockwell Automation 1788-CN2FF ControlNet-to-FOUNDATION Fieldbus H1 Linking Device User Manual - Manual (Page 5)

1788-6.5.1 - January 1999
Chapter
1
Introduction
Product Overview The ControlNet-to-F OUNDATION Fieldbus linking device connects a
ControlNet™ network with one or more F OUNDATION Fieldbus H1
(Fieldbus) networks. Each H1 network consists of multiple Fieldbus
devices. Each field device has one or more function blocks. Each function
block performs an elementary control function such as analog input, analog
output, discrete input, or discrete output. The ControlNet network consists
of controllers, such as PLC® processors, HMIs, drives, I/O devices, and so
on.
The linking device has two broad functions, supporting the following:
• closed-loop control
• configuration and monitoring
Figure 1.1 shows these functions within a simple ControlNet system.
Figure 1.1 Linking Device Function within a Simple ControlNet System
Closed-loop Control
The linking device basically permits closed-loop control between the
Fieldbus devices and ControlNet controllers. ControlNet PLC processors
can access data and control Fieldbus devices such as pressure transmitters
and valves. As an example, a PID executing on a ControlNet PLC processor
can get process values from a Fieldbus pressure transmitter and control the
position of a Fieldbus valve.
Fieldbus
Configurator/HMI
PLC
Engineering
Operator
Interface
Linking
Device
Linking
Device
ControlNet
PID
AO
H1 H1
AI
PID PID
H1 H1
AI
AO
Configuration and
Monitoring
Closed-Loop
Control