Rockwell Automation 1756-DHRIO_DHRIOXT ControlLogix Data Highway Plus-Remote I/O Communication Interface Module - Manual (Page 104)

104 Rockwell Automation Publication 1756-UM514C-EN-P - June 2014
Chapter 9 Using the 1756-DHRIO and 1756-DHRIOXT Modules in Remote I/O Applications
Module Operation in a
Remote I/O Application The 1756-DHRIO and 1756-DHRIOXT modules provide two configurable
channels that can send and receive messages over DH+ or scan remote I/O
devices. You must set the rotary switches on the module to use the 1756-DHRIO
or 1756-DHRIOXT module in a remote I/O application.
When a channel is configured for remote I/O, the 1756-DHRIO and
1756
- DHRIOXT modules are designed to function as remote I/O scanners for a
ControlLogix controller. In this case, the following occurs:
• I/O data is exchanged between the 1756-DHRIO or1756-DHRIOXT
modules and remote I/O adapters on the remote I/O link.
• I/O data is exchanged between the 1756-DHRIOor1756-DHRIOXT
module and the ControlLogix controller.
Set the channel you want to use for
Remote I/O to 1.
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IMPORTANT If you require a channel to be configured for DH+, use Channel A. By doing
so, you can connect your programming terminal to the connector on the
front of the module and communicate to devices on the network. If only
one channel is needed for RIO, use Channel B.