Data rate – Rockwell Automation 20-COMM-D DeviceNet Adapter Series B FRN 2.xxx User Manual
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G-2
Glossary
20-COMM-D DeviceNet Adapter User Manual
Publication 20COMM-UM002G-EN-P
Class
A class is defined by the DeviceNet specification as ‘a set of objects that all
represent the same kind of system component. A class is a generalization of
an object. All objects in a class are identical in form and behavior, but may
contain different attribute values’.
Connected Components Workbench Software
The recommended tool for monitoring and configuring Allen-Bradley
products and network communication adapters. It can be used on computers
running various Microsoft operating systems. You can obtain a free copy of
Connect Components Workbench software at
ControlFLASH
A free software tool used to electronically update firmware of
Allen-Bradley products and network communication adapters.
ControlFLASH software is downloaded automatically when the firmware
revision file for the product being updated is downloaded from the
Allen-Bradley updates website to your computer.
Controller
A controller, also called programmable logic controller, is a solid-state
control system that has a user-programmable memory for storage of
instructions to implement specific functions such as I/O control, logic,
timing, counting, report generation, communication, arithmetic, and data
file manipulation. A controller consists of a central processor, input/output
interface, and memory. See also Scanner.
Cyclic I/O Data Exchange
A device configured for Cyclic I/O data exchange transmits data at a
user-configured interval. This type of exchange ensures that data is updated
at an appropriate rate for the application, preserves bandwidth for
rapidly-changing devices, and allows data to be sampled at precise intervals
for better determinism.
D
Data Rate
The speed at which data is transferred on the DeviceNet network. The
available data rates depend on the type of cable and total cable length used
on the network.
Each device on a DeviceNet network must be set for the same data rate. The
DeviceNet adapter can be set to 125K, 250K, or 500K. Or, it can set to
Autobaud if another device on the network has set the data rate.
Cable
Maximum Cable Length
125K
250K
500K
Thick Trunk Line
500 m (1,640 ft.)
250 m (820 ft.)
100 m (328 ft.)
Thin Trunk Line
100 m (328 ft.)
100 m (328 ft.)
100 m (328 ft.)
Maximum Drop Length
6 m (20 ft.)
6 m (20 ft.)
6 m (20 ft.)
Cumulative Drop Length
156 m (512 ft.)
78 m (256 ft.)
39 m (128 ft.)