The Allen-Bradley ControlNet network is a state-of-the-art control network that meets the demands of real-time, high- throughput applications. The ControlNet network combines the functionality of an I/O network and a peer-to-peer network while providing high-speed performance for both functions.
The ControlNet network gives you
deterministic, repeatable transfers of all mission-critical
control data in addition to supporting transfers of
non-time-critical data. The patented media-access method
used on the ControlNet network results in deterministic
delivery of time-critical (scheduled) data by assigning it a
higher priority than non-time-critical (unscheduled) data.
As a result, I/O updates and controller-to-controller
interlocking always take precedence over program uploads and
downloads and messaging.
The ControlNet network and products such
as the ControlNet-to-DeviceNet Linking Device (catalog
number 1788-CN2DN), help deliver solutions that integrate
FOUNDATION Fieldbus devices and DeviceNet devices into a
common, seamless architecture.
All devices on the ControlNet network
have direct access to all data on FOUNDATION Fieldbus
network. The ControlNet-to-FOUNDATION Fieldbus (H1) Linking
Device (catalog number 1788-CN2FF) has many benefits:
- configuration of FOUNDATION Fieldbus
devices from the ControlNet network
- two-way data sharing between ControlNet devices and
FOUNDATION Fieldbus devices
- diagnostic feedback and monitoring of multiple FOUNDATION
networks from a single ControlNet network
- centralized controllers on a ControlNet network control
events on FOUNDATION Fieldbus networks
Flexible installation options for the
ControlNet network include:
- Redundant Media Option helps ensure
that a system can maintain operation during a cable fault
- Intrinsic Safety Option lets you install a ControlNet
network in hazardous, explosive locations. The combination
of a ControlNet 1786 fiber hub and a ControlNet Ex 1797
fiber hub allows for flawless high-speed deterministic data
flow and messaging between hazardous and safe areas. This
combination functions as an intrinsically-safe isolator
between hazardous and safe areas and can provide
The ControlNet network is simple and
cost-effective to install, and offers you flexible
installation options. A-B offers PLC processors with
built-in ControlNet scanners, ControlNet adapters for I/O
chassis, and ControlNet computer interfaces for personal
computers. Although the ControlNet network is based on bus
technology, you can use repeaters to implement tree and star
topologies. You can also install optional redundant media.
The ControlNet processors include ports that let you share
data between a ControlNet network and your already installed
Data Highway Plus and Universal Remote I/O networks.
Types of devices that communicate on the ControlNet link
include: controllers, I/O, MMIs, PCs, drives, coordinated
drive systems, weld control, motion control, vision systems,
transducers, and valve manifolds.
The ControlNet network transfers
scheduled data at 5M bit/s, which improves both I/O
performance and processor-to- processor communication. Its
flexible control system architecture can work with multiple
processors, and you can install up to 99 addressable nodes
(via taps) anywhere along the trunk cable of a ControlNet
link. There is no minimum tap separation, and you can access
the ControlNet network from every node (including adapters).
The ControlNet network provides the
functions of the A-B Data Highway Plus and Universal Remote
I/O networks at a 5M-bit/s rate. Multiple processors can
each control their own assigned outputs on a single common
ControlNet link and to each monitor all inputs on the link.
Any processor on the link can send a message to any other
processor on the link.
Messages from a node on one ControlNet link can be routed
through the ControlLogix gateway to a node on either another
ControlNet link, a DeviceNet link, a DH+ link, or an
In addition to accommodating the high
ControlNet data transfer rate and a large number of I/O
chassis, the ControlNet link provides a simple,
deterministic, flexible means of transferring I/O data.
For I/O on a ControlNet link, you can implement both
discrete and non-discrete transfers of I/O data:
- A discrete transfer of I/O data occurs
when a single unit of I/O data (8, 16, or 32 bits that
correspond to the module's I/O image) is transmitted to or
received from each I/O module in the I/O chassis. With just
one discrete transfer, you can update the I/O image for all
of the modules in the I/O chassis.
- A non-discrete transfer of I/O data occurs when a block of
data (64 words maximum in a single packet) is transferred to
or from an I/O module.