Rockwell Automation RECOMM-DNET DeviceNet Adapter for use with DPI AC Drives - Manual (Page 158)

Glossary-2 DeviceNet Adapter for use with DPI AC Drives
controller - Also called programmable logic controller. 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.
data rate - The data rate is 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. You can set the DeviceNet adapter to 125 K, 250 K, or 500 K.
You can set it to Autobaud if another device on the network has set
the data rate.
Datalink - A type of pointer used by some SP600 drives to transfer
data to and from the controller. Datalinks allow specified parameter
value(s) to be accessed or changed without using explicit
messages. When enabled, each Datalink consumes either four
bytes or eight bytes in both the input and output image table of the
controller. The drive determines the size of Datalinks.
DeviceNet network - A DeviceNet network uses a producer/
consumer Controller Area Network (CAN) to connect devices (for
example, controllers, drives, and motor starters). Both I/O and
explicit messages can be transmitted over the network. A DeviceNet
network can support a maximum of 64 devices. Each device is
assigned a unique node address and transmits data on the network
at the same data rate.
A cable is used to connect devices on the network. It contains both
the signal and power wires. Devices can be connected to the
network with drop lines, in a daisy chain connection, or a
combination of the two.
Maximum Cable Length
Cable 125 K 250 K 500 K
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)