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.
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.
