Rockwell Automation 1799-D12G12GL 12 Input/12 Output Discrete Embedded I/O - Manual (Page 11)

11 12 Input/12 Output Discrete Embedded TTL I/O Module with Pulse Width Modulation and DeviceLogix
Publication 1799-IN008A-EN-P - July 2005
Communicate with the Module
The module exchanges I/O data with the master on DeviceNet through cyclic,
polled, or change-of-state messaging.
The module consumes and produces I/O data as follows:
Messaging Type Description
Cyclic The module produces and consumes I/O data
cyclically at the rate configured by the master on the
DeviceNet network.
Polled The master initiates communication by sending its
polled I/O message to the board. The board
consumes the message, updates any outputs and
produces a response containing the input data.
Change-of-State I/O data is produced when an input changes.
A heartbeat production occurs if no input condition
change occurs within the expected packet rate. This
heartbeat production tells the master that the board
is alive and ready to communicate. Consumption
occurs when data changes and the master produces
new output data to the board.
I/O Connection Type Consumes Produces
Cyclic 3 Bytes 6 Bytes
Polled 3 Bytes 6 Bytes
Change-of-State 3 Bytes 6 Bytes