Omron DeviceNet CV Series Operation Manual page 325

Remote I/O Communications Characteristics
Slave A
Slaves in remote I/O commu-
nications with Master A
Slave A
Group A communications
cycle time: T
7-1-4 System Startup Time
System Startup Times
308
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First, the Network is divided into two groups: Master A and the Slaves in
remote I/O communications with it and Master B and the Slaves in remote I/O
communications with it.
Group A
Master A
Slave C
Slave B
Note Although in the above diagram the Slaves are separated into two groups for
convenience, the actual physical positions in the Network are irrelevant.
Next, we can refer to the previous equations and calculate the communica-
tions cycle time for each group as if they were separate Networks.
Group A
Master A
Slave C
Slave B
RM-A
In Networks with two Masters, the communications cycle time for the entire
Network will be the sum of the communications cycle times for the groups.
T = T
RM RM-A
Although this example shows only two Masters in the Network, the total com-
munications cycle time for any Network can be calculated by dividing it into
groups and adding the communications cycle times of all groups.
This section describes the system startup time for a Network operating with
the scan list enabled. The system startup time is the delay from the time that
the Master Unit is turned ON until remote I/O communications begin. Here,
we assume that the scan list is enabled and that remote I/O communications
are set to start automatically at startup.
The following table shows the system startup times for two cases. In the first
case, the Master Unit starts up just after all of the Slaves' power supplies are
turned ON. In the second case, the Master Unit is restarted while communica-
tions are in progress.
Case
The Master is started just
after Slave startup.
Group B
Master B
Slave D Slave E
Slaves in remote I/O commu-
nications with Master B
Group B
Master B
Slave D Slave E
Group A communications
cycle time: T
RM-B
+ T
RM-B
Slave's indicator status
The NS indicator is OFF or
flashing green.
Section 7-1
Slave F
Slave F
System startup time
6 seconds