Schedule import and export
You can import or export schedules under NiagaraNetwork and BacnetNetwork devices. Typically, schedules on the “import” side have “Execution Times” (time triggers) that are configured to execute manually, while those that are on the “export” side are configured to export (or push) on a daily basis or on a recurring interval.
Under the NiagaraNetwork and the BacnetNetwork, local schedules provide the ability to use the network schedule device extension. This device-level extension serves as the parent container for schedules and associated schedule import and export descriptors--components that specify how schedules are imported or exported. This also contains a Retry Trigger, see "Retry Trigger," page 4-14. The HistoryDeviceExt property sheet is shown in Figure 4-13.
Figure 4-16 shows the options available for setting update method and intervals.
Figure 4-16 Schedule device extension
To avoid unnecessary network traffic and use of CPU resources, it is important to be aware of the execution frequency and fixed execution times so that you avoid unnecessarily short execution times and duplicated (or simultaneous) network-level updates.
Schedule import and history export descriptors allow you to save a schedule to a location (station) different from where it originated. In addition to the individual import and export descriptors, this component has the following controls that can affect your network traffic.
Retry Trigger
Refer to "Common control properties", for details.
Subscribe Window
At a random time after station startup and within the time specified by the SubscribeWindow property value, all subordinate schedules who have not communicated with their supervisor will have their execute action invoked. For drivers where remote supervisors do not persist information about local subordinates, the subscribe window should be some small value rather than the default of a day. If you have many subordinate schedules, a larger Subscribe Window time decreases the chance of simultaneous schedule import or export execution.