Publication 1756-UM514B-EN-P - February 2003
8-8 Using the 1756-DHRIO Module in Remote I/O Applications
Exchanging I/O Data Between the 1756-DHRIO Module
and
Adapters
I/O data is exchanged between the 1756-DHRIO module and adapters
on the remote I/O link based on a list of adapters generated in
RSLogix 5000.
The ControlLogix controller, as the 1756-DHRIO module’s
owner-controller, downloads this list, along with the remote I/O baud
rate, to the 1756-DHRIO module. The 1756-DHRIO module then scans
each adapter (exchange I/O data) in the list in a round-robin fashion.
Exchanging I/O Data Between the 1756-DHRIO Module and the
ControlLogix Controller
I/O data and status are exchanged between the 1756-DHRIO module
and the ControlLogix controller through the producer/consumer
model used by the ControlLogix system.
Multiple connections are established between the 1756-DHRIO
module and the ControlLogix controller. These connections can be
classified in two categories. In the first category, connections are
established between the 1756-DHRIO module and the ControlLogix
controller for each adapter on the remote I/O link. I/O data is
exchanged on these connections.
In the second category, a connection is established between the
supervisor of the remote I/O on the 1756-DHRIO module (The
supervisor is the remote I/O scanner located internally on the
module.) and the ControlLogix controller. Remote I/O scanner status
is exchanged on this connection. In this case, the data exchange is
bidirectional. The 1756-DHRIO module reports status on the remote
I/O scanner, and the ControlLogix controller maintains ownership of
the 1756-DHRIO module.
IMPORTANT
Only 1 ControlLogix controller can communicate
with and own the remote I/O channels on a
1756-DHRIO module.
To Next Page
Loading...
