Table Of Contents

Calibrating a Hardware Channel at Run Time

Last Modified: June 10, 2021

Use the Channel Calibration tool to calibrate hardware channels by adjusting the values they return to known values while a system definition runs.

Before you begin, verify that you have the tool in your Workspace Tools menu. If you do not, refer to Adding a Standard or Custom Tools Menu Item. You can calibrate channels according to polynomial equations you define, custom-defined channels marked as scalable, as well as FPGA and single-point DAQ channels in running system definitions.
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Note  

If a channel has a scale mapped to it, VeriStand applies the scale first and applies the calibration to the scaled channel values second.

VeriStand supports polynomial calibrations with up to ten coefficients. A simple polynomial calibration is a linear calibration, y = mx + b, where m is the first-order coefficient (a1) that serves as the scale and b is the constant (a0) that serves as an offset.

  1. In the Workspace, select Tools»Channel Calibration to launch the tool.
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    Note  

    The name of this menu item might differ depending on how you named it in the Tools Properties dialog box.

  2. In the Channel Calibration tool under Scalable Channels, select a channel you want to calibrate.
  3. Click Next.
  4. On the User Information page, enter metadata about the specific calibration procedure you want to perform.
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    Note  

    This information is used to store the history of calibrations performed for a channel. You can view the information by clicking View History on the main page of the Channel Calibration tool.

  5. On the Polynomial Calibration Details page, enter coefficients to define the polynomial equation that will calibrate the channel.
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    Note  

    You can click Build Table and then complete a procedure for automatically calculating polynomial coefficients that best fit raw sensor values to known input values.

  6. Click Finish.
The Scaled and Calibrated Value column in the Scalable Channels table displays channel values after the calibration.

When you close the Channel Calibration tool, the calibration remains applied to the channel. Even if you close the Workspace or undeploy and redeploy the system definition, the calibration remains active until you remove it.

You also can use the Calibration VIs in the LabVIEW Execution API to automate applying calibrations and reading raw values from hardware channels.

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