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Owning Palette: DSC Module VIs and Functions

Installed With: DSC Module

Reads historical data from the Citadel database and displays the data on an XY graph. You must wire a VI Server reference of this XY graph to the Trend Reference input to use this Express VI. You must place the Historical Trend Express VI inside a While Loop.

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Dialog Box Options

Parameter	Description
Database URL	Contains the source Citadel database.
Browse	Displays the Browse Citadel dialog box from which you can select an existing Citadel database on the network.
Select Historical Data Traces	Displays a tree from which you can select one or more existing historical data traces in the Citadel database you specified in Database URL.
Add	Adds the selected item(s) from Select Historical Data Traces to Added Historical Data Traces.
Remove	Removes the selected item(s) from the Added Historical Data Traces list.
Added Historical Data Traces	Lists the historical data traces to display on the XY graph.
Automatically update every	Sets the XY graph to update the data every n seconds automatically.
Update Time	Determines the time, in seconds, between automatic updates, when you place a checkmark in the Automatically update every checkbox.
Use 'localhost' in URL?	Uses localhost as the computer name in the URL of the shared variable or trace.
Time Axis	Contains the following options: Absolute—Displays data for the period specified in Start Time and Stop Time. Relative—Displays data for the specified amount of time. Start Time—Specifies the start time of the data to display. This option is available only if you select Absolute. Stop Time—Specifies the end time of the data to display. This option is available only if you select Absolute. Display last—Specifies the amount of time to display data for a historical trend configured for relative time. The format is HH:MM:SS. This option is available only if you select a Time Axis of Relative.

Block Diagram Inputs

Parameter	Description
Trend Reference	Is the control reference to the XY graph.
Relative Time	Specifies the range of data to display, in seconds, since the current time.
Update Time	Specifies the refresh interval of the XY graph.
Database URL	Is the computer name and the database name where the Citadel database resides. Enter the database URL in the format \\computer\database_name. For example, if you have a copy of the LabVIEW Datalogging and Supervisory Control (DSC) Module and Citadel service installed on a computer named datalogger and the name of the database on that computer is data, you can access the data on datalogger from another computer by using the path \\datalogger\data. If you provide a database name only, the DSC Module searches for the database on the local computer. If you do not wire database URL, the VI reads data from the database associated with the default DSC Module process.
error in	Describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
Shared Variable List	Lists the shared variables to display on the XY graph. This list corresponds to the Added Historical Data Traces list on the configuration dialog box of this Express VI.
Start Time	Specifies the start time of the data to display on the XY graph.
Stop Time	Specifies the stop time of the data to display on the XY graph.

Block Diagram Outputs

Parameter	Description
error out	Contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces.
historical traces	Contains the array of historical data points retrieved from the database. Wire this output to an XY graph.