Scheduled Items - BCPro - LIT-12011905 - Server - BCPro Data Server - 4.0

BCPro Data Server

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BCPro Data Server
Document type
User Guide
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Scheduled items are the objects/attributes that the event values are written to. A schedule can operate with an empty Scheduled Items list. The scheduling feature writes the defined value to the scheduled items at the time defined by an event. Schedules can reference any item that can be mapped into a BCPro Workstation. Schedules defined in an FAC can reference items within that FAC even if not mapped to a supervisory device. Adding items to a schedule involves selecting the item and then selecting the attribute of the item that you want the schedule to change. At the times defined by an event, the schedule writes the defined values to the attribute (scheduled attribute) associated with each referenced item.

When there are no events active in the weekly schedule or exceptions, the schedule writes the Default Schedule Command to the referenced attributes. If the Default Schedule Command is set to Release, the schedule’s control over the scheduled items ends.

Note: Release should only be used for the Default Schedule Command if the scheduled items support the Release command.

The table of scheduled items provides the Status Log entry for each scheduled item. The status log indicates any errors that occurred when the scheduling feature attempted to write values to the scheduled items.

A single schedule can only apply values of one data type to all items in its list of scheduled items; therefore, the first item in the Scheduled Items list becomes the key item. The key item determines the data type of the values that the schedule writes to the attributes of all scheduled items. See the following Example Scenario for a description of how scheduled items and the key item work.

Example Scenario:

You can close a relay or switch to start a fan. If the relay is represented as a Binary Output Object in the BCPro system and you set the Present Value attribute of the BO to On (1), the relay closes and starts the fan. To do this, add the BO to the Scheduled Items and then select Present Value as the scheduled attribute. See Adding Scheduled Items and the following figure.
Figure 1. Table of Scheduled Items

Suppose the BO in this scenario is the key item because it is the first item in the list of scheduled items and the Present Value attribute is the scheduled attribute. Because the Present Value attribute of a binary output has a value of 0 or 1, the schedule can only write 0 or 1 to the scheduled attributes of the items appearing below it in the list.

Suppose you add an Analog Value Object below the BO and select the Present Value attribute of the AV as the scheduled attribute. Even though the Present Value attribute of an AV has a wide range of numeric values, only 0 (meaning Off) or 1 (meaning On) can be written to the AV attribute because the schedule writes values to all items in the list of scheduled items using the data type of the BO, which is the key item.

To change the key item, see Editing Scheduled Events.