Allen-Bradley devicenet modules in logix5000 control systems Manual Do Utilizador
Publication DNET-UM004A-EN-P - March 2004
Before You Begin 1-5
Choose a Scanner
The DeviceNet scanner connects a controller to the devices on a
DeviceNet network.
DeviceNet network.
To organize your devices into a DeviceNet network, either:
scanner
module
device
device
device
Input
Memory
DINT
DINT
DINT
Output
Memory
DINT
DINT
DINT
controller
The scanner collects input data from
the devices on the network…
the devices on the network…
…and sends the data to the devices.
…and sends the data to
the controller.
the controller.
controller
data
The scanner collects output
data from the controller…
data from the controller…
This option:
Has these advantages:
And these disadvantages:
single network
• lower cost
• 1 network to manage
• scanner is local to the controller
• 1 network to manage
• scanner is local to the controller
• shorter distances
• more devices on the network = slower
• more devices on the network = slower
performance on that network
• more power supply requirements
subnets
• shorter runs on subnets, more total distance
• fewer devices on the subnet = faster performance
• fewer devices on the subnet = faster performance
on the subnet
• simpler power supply requirements
• higher cost
• multiple networks to manage
• scanner is remote from the controller
• multiple networks to manage
• scanner is remote from the controller
device
device
device
device
Place all your devices on a single network and
connect the controller directly to the network via
the scanner.
device
scanner
controller
device
linking
device
device
device
controller
device
linking
device
device
device
device
Break up your devices into several smaller
distributed networks (subnets). Place a scanner
(linking device) on each network. Connect the
scanners to the controller via an EtherNet/IP or
ControlNet network (backbone).
main network
subnets