Data Highway Plus Industrial Local
Area Network Overview
The Data Highway
Plus (DH+) network is a local area network that is very
simple to implement. It is designed to provide simple
communication between PLCs, SLCs and PCs.
The Data Highway Plus network allows
connection to a maximum of 64 devices per link (although 15
or fewer nodes are recommended per link), including:
* PLC-5 and SLC 5/04 programmable
* Color graphics systems
* Personal computers
* Host computers
* Numerical controls
* Programmable RS-232-C/RS-422 devices
A network can be configured with 99
links. With a multi-link network, more nodes in the network
are possible. By placing nodes in the proper link with some
nodes and separate from other nodes, the efficiency of
message delivery can be improved. Using simple twisted-pair
wiring, DH+ can be configured as a trunk-line drop or a
Use Rockwell Software Programming
Software to program the PLC controllers over the Data
Highway Plus network, or program a PLC controller from its
local DH+ link or from a remote DH+ link in the network.
This means that a single industrial terminal connected to
the network can be used to program all the PLC controllers
on all links of the network.
The ControlLogix Communication Interface Module (1756-DHRIO)
interfaces two DH+ links to the ControlLogix backplane to
provide routing of messages between a DH+ link and EtherNet/IP,
ControlNet, DeviceNet, and other DH+ links.
Data Highway Plus modules can also be used to implement a
* Includes switches on each interface
that make it easy to reconfigure the network as it changes.
* Incorporates network diagnostics that help the user avoid
costly downtime and improve network efficiency.
* Allows for use of communication software to provide a Data
Highway Plus communication driver to various computer
||(1770-CD shielded twinaxial):
• trunkline - 10,000 ft max.
• droplines - 100 ft max.
||• token passing
• 57.6 kbit/s
• 230 kbit/s on selected products
||• 1770-KF2: 0…50 °C (32…122 °F)
• all other Data Highway Plus backplane-resident
modules: 0…60 °C (32…140 °F)