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Section 4
DeviceNet Connection Settings
DeviceNet Connection Settings
DeviceNet supports different protocols for remote I/O communications between master
and slave devices. Connection is a unit used to manage those protocols. The connections
can be set using the configurator.
The DeviceNet remote I/O communications protocol supports four types of connections:
Poll, Bit-Strobe, COS (Change of state), and Cyclic.
The features of these connections are listed in the following table.
communication unit supports all the protocols.
Connection
Poll
Bit-Strobe
COS
(Change of
state)
Cyclic
To use COS and Cyclic connections, the DeviceNet master must support those functions. Confirm that
the master supports COS and Cyclic connections before using them.
OMRON products, such as the CS1W-DRM21 and CJ1W-DRM21, support COS and Cyclic
connections.
Setting Connections without Using Configurator
The connections used for all the IN data of the Sensor communication unit are as follows:
• Data of 8 bytes or less: Bit-Strobe
• Data of more than 8 bytes: Poll
E3X-DRT21-S
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User's Manual
Used for basic I/O.
Used for input of 8 bytes or less.
Sends broadcasting requests from master
and receives input from slaves.
This connection can be used to send data to the master from the
communication unit only when the data changes.
Transmission timing is determined by a heartbeat timer.
Data can be sent only when required, thereby reducing the
communications load on the network.
Communications timing is determined by regular cycles (heartbeat
timer).
The communication unit will send data at a regular cycle.
Description
The Sensor
Poll and Bit-Strobe
connections
cannot be used
at the same time.
COS
and
Cyclic
connections
cannot be used
at the same time.
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