
1.DeviceNet FUNCTIONS SETTING B-64044EN/01
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Communication cycle time
This time is measured from when I/O data communication to the slave
with a certain node number is processed until I/O data communication
to the slave with the node number is processed again. The
communication cycle time depends on whether the number of masters
on a network is only one or more than one, whether the Explicit
message communication was performed, or other factors.
When the number of masters on a network is only one, it is
recommended that the normal communication cycle be set to 0 (fastest
value).
However, the communication cycle time needs to be changed when,
for example:
1 There are multiple masters on a network.
2 I/O data needs to be updated at predetermined time intervals
rather than the shortest time intervals.
NOTE
For a network on which multiple masters are
present, follow a procedure as described below to
determine the communication cycle time.
Example) To set the communication cycle time for
a network on which two masters are
present:
<1> Configure a network with only this master and
the slaves that communicate with this master.
<2> Set the communication cycle time of this
master to 0.
<3> Measure the maximum communication cycle
time (T1) of this master.
<4> Similarly, configure a network with only the
other master and the slaves that
communicate with the other master and
measure the maximum communication cycle
time (T2) of the other master.
<5> The communication cycle time of this master
is (T1 + T2 + α). The communication cycle
time of the other master is also (T1 + T2 + α).
The value of a represents an arbitrary time
value.