Configure EMG devices

EMG data can be acquired through the analog capture functionality of a Vicon connectivity device. If your EMG device 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 more information on the digital data streams that can be used with your Vicon system, contact Vicon Support.

To configure EMG devices for data capture:

1. If Vicon Nexus is not in Live mode, 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 EMG device before it will be displayed in the System Resources pane.
2. In the System Resources tree, right-click Devices, point to Add Analog Device or Add Digital Device and from the context menu select the type of EMG device that is integrated in your Vicon system.
   The Devices node automatically expands to display the newly created EMG device with its attendant output:
   
   • An analog Accelerometer will have an Acceleration output
   • An analog EMG will have a Voltage output
   • A ZeroWire EMG will have a Voltage and a Foot Switch output

3. In the System Resources tree, select the node whose properties you wish to edit:

   • Generic Analog Device sub node for all devices
   • A sub node for a specific device
   The colored icon beside a device node identifies the status of the device and of any connected source:

   Green play button: Component OK (active or connected); if an analog device is connected, the 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).

4. 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 to enable you to identify the device.
      • Set the Delay Compensation (in frames). All devices have a delay compensation value which adjusts the synchronization offset between the device and the Vicon data. The Delay Compensation slider bar enables you to correct this difference. Values can be set between -10 and 10 (the default is 0). Note that analog data collected with a Vicon Lock is already synchronized, so in this case, set this value to 0.
      • Set the Amplifier Gain. The voltage gain scale factor. Can be set between 1–1000. The default setting depends on the device.
   2. In the Source section, select a Source (the Vicon connectivity device to which the accelerometer or EMG is attached) from the list.
   When you first set up your Vicon system, you must configure at least the Name and Source properties, add channels and designate the Source for each channel. In subsequent sessions, you may wish to configure additional properties to suit your needs.
5. In the System Resources tree, expand the device node you added and select a device output sub node which corresponds to an output from the device (such as Acceleration for an accelerometer, or Voltage for an EMG device).
6. Right-click the device output and add an output component or components:
   For an accelerometer or analog EMG, choices are:
   
   • Add Component (or 2, 4, or 8 Components)
   For a ZeroWire EMG, choices are:
   Under Voltage:
   • Add EMG (numbered 1 - 16)
   • Remove Channels (if you have added channels)
   • Enable Auto Populate (or Disable Auto Populate if the AutoPopulate Properties box is selected)
   Under Foot Switch:
   • Add FSW (designated A1-A4 and B1-B4)
   A new component node (or nodes) is added to the tree.
   The colored icon beside the device output node identifies the analog channel status:
   • Green arrow: Analog channel connected to source device.
   • Yellow arrow: Analog channel not fully set up (e.g., not all channels have been assigned a pin or the calibration matrix has not be configured).
7. In the Properties pane under the General section, specify a Name for the node or nodes you have added.
   For the ZeroWire EMG, Name is the only property setting necessary.
8. In the Properties Source section:
   
   1. Assign the Pin to one of the available pins on Source device. After you have assigned a pin, the status icons will turn green.
   2. Specify the Gain (V).
   3. Set the Zero Level.
9. 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).

For more information on the properties for EMG and other devices, see System Resources nodes

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