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Real-Time Trend Express VI

LabVIEW 2013 Datalogging and Supervisory Control Module Help

Edition Date: June 2013

Part Number: 371618J-01

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Owning Palette: DSC Module VIs and Functions

Requires: DSC Module

Reads live data from shared variables and displays the data in a waveform chart. You must wire a VI Server reference of this waveform chart to the Trend Reference input to use this Express VI.

Dialog Box Options
Block Diagram Inputs
Block Diagram Outputs

Dialog Box Options

ParameterDescription
Shared Variable ListContains the following options:
  • Project Items—Lists all shared variables in the active project.
  • Network Items—Lists all shared variables and data items in other projects or on the network.
  • Custom URL—Displays the network path to a shared variable. Enter the URL in the format \\computer\process\shared_variable.
AddAdds the selected item(s) from Shared Variable List to the Added Shared Variable List.
RemoveRemoves the selected item(s) from the Added Shared Variable List.
Added Shared Variable ListLists the shared variables to display in the waveform chart.
Time between updatesSpecifies the time to wait before attempting to read data from the network.
Engineering unitsCharts the data based on unit value.
Percent of full scaleCharts the data as a percentage of the data range.

Block Diagram Inputs

ParameterDescription
Scale To (%)Specifies the mode to chart the data. Set this input to TRUE to use engineering units. Set this input to FALSE to use a percentage of the full scale.
Shared Variable ListLists the shared variables to display in the waveform chart.
Time Between Updates (s)Specifies the time to wait before attempting to read data from the network.
Trend ReferenceSpecifies the control reference to a waveform chart.

Block Diagram Outputs

ParameterDescription
Trend DataReturns the real-time data points to display. Wire this output to a waveform chart.
errorReturns any error or warning condition from the Express VI.
ShutdownReturns whether the shared variables are live. If this parameter is FALSE, the data that appears on the waveform chart is live shared variable data. If this parameter is TRUE, the shared variable has no value and the waveform chart displays a flat line.

 

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