Insert the terminal block, Communicate with the 1791d module – Rockwell Automation 1791D-XXXX CompactBlock I/O for DeviceNet Modules Series D I.I. User Manual
Page 15
 
CompactBlock I/O for DeviceNet Modules Series D 15
Publication
1791D-IN003A-EN-P - June 2003
Insert the Terminal Block
To insert the CompactBlock terminal block.
1. Insert the terminal block by aligning it and pushing it back
until it rests against the back of the module.
2. Tighten the screws on each side of the terminal block until the
terminal block is firmly in place.
Communicate With the 1791D Module
Determine the Baud Rate for Your DeviceNet Connection
All 1791D CompactBlock I/O for DeviceNet modules contain the 
autobaud feature. Autobaud lets the modules automatically detect the 
baud rate for the network upon connection to the live network.
The 1791D base modules’ I/O is exchanged with the master through 
a polled, cyclic or change of state connection.
Polled - master initiates communication by sending its polled I/O 
message to the 1791D module. The module consumes the message, 
updates any outputs, and produces a response. If inputs are present, 
the response contains the input data.
Cyclic - allows configuration of the block as an I/O client. The block 
will produce and consume its I/O cyclically at the rate configured.
Change of state - production occurs when an input changes. If no 
input change occurs within the expected packet time, a heartbeat 
production occurs. This heartbeat production tells the scanner 
module that the 1791D I/O module is alive and ready to 
communicate. Consumption occurs when data changes and the 
master produces new output data to the I/O block.