8 Communications Timing
8-8
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
This section describes the system startup time (estimated) for a network operating with the scan list
enabled. The system startup time is the delay from when the controller is reset or restarted including
turning ON the DeviceNet Unit (master) 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 2 cases. In the first case, the DeviceNet Unit
starts up just after all of the Slaves' power supplies are turned ON. In the second case, the DeviceNet
Unit is restarted while communications are in progress.
As shown in the preceding table, it takes time for DeviceNet communications to start up. This pro-
gramming uses flags in the Master status area to prevents the Slaves' I/O processing from being
performed until remote I/O communications start up.
This programming is for a DeviceNet Unit with a unit number of 00.
8-1-4 System Startup Time
Master Function
Case Slave's indicator status System star-
tup time
(estimated)
The Master is
started just after
Slave startup.
The NS indicator is OFF or flashing green. 13 seconds
Just the Master is
restarted.
The NS indicator is flashing red while the
Master is OFF.
15 seconds
Just the Slaves are
restarted.
--- 9 seconds
Program Example
aaaa_Mstr1IOCommSta
I/O Data Communications Status
STEP1
STEP1:
Processing other than slave I/O
Slave I/O processing
aaaa_UnitErr
Unit Error
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