Rockwell Automation 1756-DHRIO_DHRIOXT ControlLogix Data Highway Plus-Remote I/O Communication Interface Module User Manual
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Rockwell Automation Publication 1756-UM514C-EN-P - June 2014
Chapter 2
Using the Data Highway Plus Network
controller slot for port A is configured to “0”, the message is forwarded to the
ControlLogix controller in slot 0.
Receiving Local DH+ Messages on DH+
Because a local DH+ message has only enough address information to get the
message to a target node on the same DH+ network, the 1756-DHRIO and
1756-DHRIOXT modules that receive this message cannot identify where to
send the message. The 1756-DHRIO and 1756-DHRIOXT modules use the
Controller Slot configuration parameter to send the message to the local
controller.
You must use RSLinx software to configure the controller slot. For more
information on setting the controller slot, see page
.
Some messages, called PCCC commands, are not sent to the controller slot. In
this case, the 1756-DHRIO and 1756-DHRIOXT modules generate a response
to the message. For a complete list of these messages, see
Local DH+ messaging does not require a populated routing table. Local DH+
messaging does require a default (that is a properly emptied) or an applied (that is
a properly populated and saved) routing table, and a default or applied controller
slot for each channel configured for DH+. For more information on routing
tables, see
,
1756- DHRIO
PLC-5 Controller B
Node Number: 025
Channel A
Node Number: 010
Controller Slot=0
ControlLogix Controller
41458
IMPORTANT
Local DH+ Messaging can target only one ControlLogix controller per DH+
channel. The ControlLogix controller must reside in the same chassis as the
1756-DHRIO and 1756-DHRIOXT modules receiving the message.