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Scaling Page (DSC Module)

Select the Scaling option in the listbox of the Shared Variable Properties dialog box to display this page. Use this page to configure scaling for shared variables.

Note  You can use scaling only for network-published shared variables. The shared variable you want to scale also must have a data source. Configure a shared variable to have a data source by placing a checkmark in the Bind to source checkbox on the Variable page of the Shared Variable Properties dialog box.

This page can include the following components:

  • Enable Scaling—Enables LabVIEW to scale the shared variable value.
  • Scale Type—Sets the type of scaling to use when communicating with the data source. Different types of scaling are available depending on the data type of the shared variable.
    • Linear—Performs linear scaling between the Raw Scale and the Engineering Scale for shared variables with a Data Type of Double.
    • Square Root—Performs a square root operation when converting from the Raw Scale range to the Engineering Scale range for shared variables with a Data Type of Double. The following equation defines the square root operation: b + m * sqrt(raw – o) where b = Engineering Zero Scale, m = (Engineering Full Scale – Engineering Zero Scale)/sqrt(Raw Full Scale – Raw Zero Scale), and o = Raw Zero Scale.
    • Invert—Inverts the data sent by the data source. Use this scaling type for shared variables with a Data Type of Boolean.
    • Bitwise—Scales the data by bit. Use this scaling type for shared variables with a Data Type of U32 Bit Field.
  • Engineering Unit—Specifies the engineering unit for the shared variable.
  • Raw Full Scale—Specifies the maximum value of the scale you want to use to collect the data from the data source. The raw scale is the original scale that you used to collect the data. The Raw Full Scale value must be greater than the Raw Zero Scale value. This option appears for shared variables with a Data Type of Double.
  • Engineering Full Scale—Specifies the maximum value the Shared Variable Engine and HMI application use to scale the data source. The engineering scale is the full range that you want the Shared Variable Engine to use to scale the data source. This option appears for shared variables with a Data Type of Double.
  • Raw Zero Scale—Specifies the minimum value of the scale you want to use to collect the data from the data source. The raw scale is the original scale that you used to collect the data. The Raw Zero Scale value must be less than the Raw Full Scale value. This option appears for shared variables with a Data Type of Double.
  • Engineering Zero Scale—Specifies the minimum value the Shared Variable Engine and HMI application use to scale the data source. The engineering scale is the full range that you want the Shared Variable Engine to use to scale the data source. This option appears for shared variables with a Data Type of Double.
  • Coerce to Range—Coerces the data to the specified range so it is valid. If you scale the data for a shared variable you can write, the data must be within the Raw Scale range. If you scale the data for a shared variable you can read, the data must be within the Engineering Scale range. This option appears for shared variables with a Data Type of Double.
  • Invert—Inverts data sent by the data source before storing it in the shared variable. This option appears for shared variables with a Data Type of Boolean.
  • Scaling Invert Mask—Determines which bits the Shared Variable Engine inverts before storing them in the shared variable. This option appears for shared variables with a Data Type of U32 Bit Field. The Shared Variable Engine inverts bits in the mask with value 1 but does not invert bits with value 0. The default invert mask is 0, indicating that the Shared Variable Engine inverts none of the bits. In bitwise logic terminology, the Shared Variable Engine performs an XOR with the Scaling Invert Mask value to produce the scaled value.
  • Edit—Displays the Edit Bit Mask dialog box. This option appears for shared variables with a Data Type of U32 Bit Field.
  • Scaling Select Mask—Determines which bits the Shared Variable Engine uses for the shared variable. This option appears for shared variables with a Data Type of U32 Bit Field. The Shared Variable Engine stores bits in the mask with value 1 in the shared variable. The Shared Variable Engine sets bits in the mask with value 0 to 0, regardless of the value received from the server. In bitwise logic terminology, the Shared Variable Engine performs an AND with the Scaling Select Mask value to produce the scaled value.
  • Edit—Displays the Edit Bit Mask dialog box. This option appears for shared variables with a Data Type of U32 Bit Field.

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