Rockwell Automation 1771ACN/B_1771ACNR/B,D17716.5.123 U.MNL CONTROLNET ADAPTER - Manual (Page 37)

Chapter
4
Publication 1771-6.5.123 – May 1996
Planning to Use Your
ControlNet Adapter Module
This chapter explains how the adapter operates on ControlNet and
provides information to assist in configuring your system. This
includes:
•
overview of adapter operation
•
discrete I/O data transfer
•
configuring discrete I/O data transfers
•
nondiscrete I/O data transfers
•
using ControlNet I/O (CIO) instructions
•
mapping directly into processor memory, including examples of
nondiscrete input module and output module communication
•
configuring nondiscrete I/O data transfers
The controlling processor (network address 01) on ControlNet
contains an I/O map table. This map table stores the information
necessary for communications to be established. Each map table
entry corresponds to 1 transfer of data between the processor and an
I/O rack, or between the processor and another ControlNet processor.
The information in each map table is used to open a logical
“connection” between 2 devices.
Connections are established between the processor and each adapter
to exchange input and output data on the network. Status information
is transferred along with the I/O data and is stored in a separate
status file in the specified processor. Refer to the ControlNet PLC–5
Programmable Controller Use Manual, publication 1784-6.5.14, for
more on status information available.
Important: The processor compares the specified module type (in
the map table) with the device with which
communication is being attempted. Therefore, when
changing from a 1771-ACN to a 1771-ACNR, or vice
versa, you must specify the new module type in the map
table.
Chapter Objectives
Overview of Adapter
Operation