Content Comparison

...

Force plates data can be acquired through the analog capture functionality of a Vicon connectivity device (Vicon Lock+ or MX Giganet). This topic describes the analog connection only. If your force plate has a digital output, it is possible that this data stream can also be captured, but this depends on the data stream's format and the equipment's manufacturer. For information on the digital data streams that can be used with Vicon systems, contact Vicon Support.

...

1. In the System Resources pane, click the Go Live button.
   The first time you use Nexus, the Devices node is empty. You must add and configure a new force plate device before it will be displayed in the System Resources tree.
2. In the System Resources tree, right-click the Devices node, point to Add Analog Device and from the context menu select the type of force plate that is integrated in your Vicon system.
   The selected force plate node automatically expands to display the newly created device. (For Motekforce Link treadmills, two new device nodes are displayed, one for each plate.) If the appropriate type is not displayed, contact Vicon Support.
   The colored icon beside a force plate node identifies the status of the device and of any connected analog source:

   • Green play button: Component OK (active or connected); if an analog device is connected, the analog source is selected and all channels are configured.

   • Yellow pause button: Component is not fully set up (e.g., not all channels have been assigned a pin or the calibration matrix has not been configured).

   • Gray play button: Component connected but not contributing any data.

   • Red stop button: Component down (unavailable or disconnected).

   
   These colored icons correspond to those used for the device summary in the Status Communications pane.

   Scroll pagebreak

3. In the Properties section at the bottom of the System Resources pane, view or change settings for the following properties:
   
   1. In the General section, enter a Name.
   2. In the General section, go to the Calibration File field, and load the manufacturer's calibration file:
      
      • If the calibration file is not listed in the drop-down list, click the ellipsis (...) next to the Calibration File field to browse to the relevant location, and select it. The file becomes available in the drop-down list.
      • Select the calibration file. (For Motekforce Link treadmills, note that a single calibration file is used for both plates.)
      • If not supplied by the manufacturer's calibration file, you can set the device Dimensions, Position, Orientation, and Origin in those Properties sections.
   3. If there is no calibration file, click Show Advanced at the top right of the Properties section and enter the Calibration Matrix 6x6 Matrix values manually.
      Important: For the force plate to become active, you must enter the Matrix values, either via a calibration file or by manual entry.
   4. In the Source section, select a Source (the Vicon connectivity device to which the device is attached) from the drop-down list.
      The Source drop-down list contains all connected Vicon connectivity devices; a USB force plate will have its Source drop-down list populated with connected USB devices of the required type.
   5. In the Source section, use the Fill button to populate the input connections sequentially (if these are consecutive on the Vicon connectivity device).
   6. In the Source section, select the Gain for the Source from the choice of gains available for the Vicon connectivity device.
      

      Scroll pagebreak

4. In the System Resources tree, if necessary, expand the force plate node to expose the Force, Moment and CoP (Center of Pressure) channels.
   The colored icon beside the output node identifies the analog channel status:
   
   • Green arrow: Analog channel connected to source device.
   • Yellow arrow: Analog channel has not been assigned a pin.
5. To tare the force plate at zero load, in the General section, click the Zero Level browse button and enter the matrix properties.
   Tip: You can also tare the force plate by right-clicking on the force plate name in the System Resources tree and selecting Zero Level.
6. In a 3D Perspective view, ensure that a gray or colored rectangle with the number 1 on it, representing the force plate, is displayed in the capture volume where you have positioned it.
   If you have multiple force plates configured, they will be numbered in the order they appear in the System Resources tree.
7. In the capture volume, have someone step onto the force plate. You should see the force vector being displayed in real time.
8. At the top of the System Resources pane, click the Save button to save your system configuration settings to a .system file in the Systems configurations folder (see Manage configurations in Vicon Nexus).
9. From the System Resources tree, expand the force plate node and select the Force output.
10. Switch to a Graph view.
11. If necessary, select Components from the Graph Type drop-down list. A real-time graph of the Force output is displayed.
12. Verify that the vertical (Fz) force component is equal to [known mass * 9.81].

...

See also Force plate properties in the Vicon Nexus Reference Guide.

...

Values below the Force Threshold (N) are not visualized as force vectors on the plate. This setting does not affect the value for Force Threshold that is written into a recorded trial (see Visualize and record Force Threshold).

Moment Vector section

You can select whether the moment vector is visually represented in the 3D Perspective view, as well as the quality, radius and color of the moment vector display.

...