Rockwell Automation 1756-DHRIO_DHRIOXT ControlLogix Data Highway Plus-Remote I/O Communication Interface Module - Manual (Page 146)

146 Rockwell Automation Publication 1756-UM514C-EN-P - June 2014
Chapter 12 Block Transfers with the 1756-DHRIO or 1756-DHRIOXT Module
Block Transfer ‘Pass-Through’
Messages DH+ ‘Block Transfer (BT) Pass-Through’ messages are DH+ (PCCC) messages
sent to an remote I/O channel, where it causes an remote I/O Block Transfer.
To target a DH+ ‘BT Pass-Through’ message to an remote I/O channel on a
1756-DHRIO or 1756-DHRIOXT module, the final destination of the DH+
message must be the 1756-DHRIO or 1756-DHRIOXT module with the
remote I/O channel.
In the case of Local DH+ Messaging, the bridging 1756-DHRIO or
1756-DHRIOXT module must have its default slot configured to match the
location (slot) of the final destination 1756-DHRIO or 1756-DHRIOXT
module (module with the remote I/O channel).
In the case of Remote DH+ Messaging, the destination link ID and destination
node of the DH+ message must be set to the final destination 1756-DHRIO or
1756-DHRIOXT module (module with the remote I/O channel).
For example, if the target is an remote I/O channel on a 1756-DHRIO or
1756-DHRIOXT module in slot 5 of a ControlLogix chassis and remote DH+
messaging is used, the destination link ID is set to the ControlLogix chassis link
ID and the remote destination node is set to 5.
Block Transfer Examples
IMPORTANT To send DH+ ‘Pass-Through’ messages to a 1756-DHRIO or 1756-DHRIOXT
module, the module must be configured with a routing table, as described
in Chapter 2, even if the channels are configured for remote I/O.
IMPORTANT In the examples in this chapter, only channel B is connected to remote I/O.
You can connect the channels to remote I/O simultaneously if necessary.
If only one channel is connected to remote I/O, it is recommended that you
use channel B. If you connect channel A to remote I/O, you cannot use the
programming terminal on the front of the 1756-DHRIO or 1756-DHRIOXT
module.