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Operational Flow and Cycle Time Section 9-2
9-2 Operational Flow and Cycle Time
The NE1A-series Controller’s operations are outlined here.
The NE1A-series Controller initializes itself internally when the power is
turned ON. Unless there are errors, the Controller then cyclically executes
system processing,
DeviceNet/USB communications processing, I/O refreshing, and user pro-
gram.
In Standalone Controller mode, the Controller cyclically executes all but the
DeviceNet processes. The cycle time depends on the scale of the user pro-
gram and the configuration of DeviceNet remote I/O communications.
Note Approximately 6 s is required to complete initialization after the power is
turned ON. Initialization processing includes the self-diagnosis required for
the NE1A-series Controller to perform safety functions.
The cycle time is expressed by the following formula.
Controller cycle time = System processing time
+ DeviceNet/USB or USB communications time
+ I/O refresh time
+ User application execution time
The cycle time of the NE1A-series Controller is set in 1-ms increments
depending on the configuration. The cycle time can be checked from
the Network Configurator.
Note After the NE1A-series Controller has started operating, DeviceNet connection
will be established and then devices will be verified to start DeviceNet safety
I/O communications. This process can take up to 2 s to be completed depend-
ing on the configuration (i.e., on the setting for the number of connections).
The following formula gives the time from the when the processing to estab-
Initialize
System processing
DeviceNet/
USB communications
processing
I/O refresh
User application
calculation
Cycle time
Initialize
USB communications
processing
I/O refresh
Normal mode flow Standalone Controller mode flow
Power ON Power ON
System processing
User application
calculation
Cycle time
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