Polling; Change Of State, Cos - Danfoss VLT 2800 Manual

I Polling
This is the standard Devicenet operation mode,
meaning that data can be acquired by the master via
polling using the Devicenet or Danfoss objects.
I Change of State, COS
This operation modus can be used in order to
minimize network traffic. Messages are only sent to
the consumer, if a defined state or value has changed.
In order to signalize, that the connection has not been
crashed or is powered off, a Heartbeat Message is
transmitted within a specified time (Heartbeat Interval).
This time is defined in attribute heartbeat time of the
connection object class code 0x05. To prevent the
device from producing heavy network traffic, if a value
often changes, the Production Inhibit Time (attribute of
connection object) is defined. This parameter defines
the minimum delay between 2 c-o-s messages.
The Attribute Expected Package Rate defines
the maximum time between two Cos messages
even though the value has not changed. Cos
operation modus can only be used on I/O
instances defined in parameter 904.
Parameters 834 through 837 can be used for filtering
out undesired events for Cos. If a filter bit is set
to 0, the corresponding I/0 instance bit will not
be able to produce a Cos message.
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VLT 2800 / FCD 300 DeviceNet
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