1756-DHRIO Controllogix Data Highway Plus DH+ Communication Module

The Data Highway Plus/RIO module performs the following functions:

*Data Highway Plus™ (DH+) Messaging

*CIP Messaging

*Remote I/O

You can send messages between DH+ nodes and other networks which include ControlNet, Ethernet, or other DH+ Networks.  A 1756-DHRIO acts as a scanner by using Remote I/O capabilities. The module exchanges discrete and block transfer data within remote i/o devices. This module gives connectivity between numerous remote I/O adapters.

Messaging between AB DH+ and CIP
The 1756-DRHIO provides a way for information to be transfered between devices between PLC-5s, SLCs and other Controllogix for the following:
• Different network Communications between with PLC-5s or SLCs
• Different network Communications between ControlLogix processors and a PLC-5s or SLCs.
• Different network Communications Between ControlLogix processors.

Details on Data Highway Plus:

Data Highway Plus is a cable or wire with a protocol that provides intercommunication between PCs and devices.  The

networking cable used is named the network medium.  A DH+ connections moves data between PLCs on DH+ such as PLCs, SLCs and ControlLogix processors and other DH+ nodes. You can interface up to 32 stations to one DH+ connections.


ANC-100e, RSLINX Ethernet/IP to Allen-Bradley Data Highway Plus (DH+) Gateway Converter Series. $1,195 USD List. The ANC-100e is an economical and high performance, “pocket-sized” converter interfacing Factory Automation Devices between Ethernet/IP and PLC-5s & SLC-504s on Allen-Bradley Data Highway Plus DH+. This is an alternative converter solution to the 1756-DHRIO / 1756-ENBT Controllogix Gateway.
(ANC-120e, USB-to-Data Highway Plus, 1784-U2DHP replacement alternative also available using the Controllogix Ethernet/IP Driver feature).

Connection Design:

Upon creating your DH+ connection, you should use the best design by laying out the overall ahead of time. It is a good idea when designing your DH+ to consider the following:

• All performance neccesities

• Maintenance

• Future additions to the Network

The best cable options is 1770-CD (Belden 9463) cable when interfacing your 1756-DHRIO processor to DH+.  A daisy chain or trunk line/drop line system is how setup the DH+ configuration.

Recommendations for Trunk Line/Drop Line include:

Using connectors that include 1770-SC and cable-lengths that consider:

• trunk line-cable length – depends on the communication rate of the link

• drop-cable length – 30.4 m (100 cable-ft.)

Source Allen-Bradley.