For Motive 1.10 and above, National Instruments data acquisition (NI-DAQ) devices can be integrated into OptiTrack motion capture systems. Through NI-DAQ devices, analog signals from various devices (e.g. transducers or EMG sensors) can be converted into digital signals at a user-defined sampling frequency, and they can be precisely synchronized with the tracking data. This page provides instructions on connecting NI-DAQ devices and acquiring analog signals within Motive. Please refer to the list of recommended NI-DAQ models included at the end of the page regarding supported models. For instructions on configuring the NI-DAQ devices, please refer to the respective product User Guide or the NI's getting started guide.
Integration of NI-DAQ device(s) uses the OptiTrack Peripheral Module (OPM) to register, initialize, and record using the connected DAQ device(s) in Motive. When properly configured, up to 16 analog channels from each of the connected NI-DAQ devices and sampled voltage signals can be captured. Recorded analog data can be saved into the Take (.TAK) file along with the motion capture data, and it could also be exported into C3D files for further analysis.
In order to precisely align the recorded signals with the tracking data, the eSync synchronization hub must be used. Specifically, the NI-DAQ device(s) needs to synchronize with the internal clock signal of the camera system from the eSync. In order to accomplish this, the NI-DAQ device(s) must support the sample clock signal, and they must be connected to an OptiTrack system through the eSync. Integration with camera systems without an eSync is feasible, but the clock signal will not be available for synchronization. In this case, the NI-DAQ device(s) will run at its Free Run mode with individually assigned acquisition rates, but the synchronization of the recorded signals and the tracking data will be off.
The integration supports analog voltage input channels only.
- OptiTrack Motion Capture System
- Motive 1.10 and above with a valid license.
- OptiTrack Peripheral Module.
- NI-DAQ device(s): PCI or USB. See more at Supported Devices.
- Third party analog devices.
- The eSync synchronization hub for precise synchronization using its clock signal.
- The NI-DAQ functionalities are not supported with the use of the Motive API.
- Follow the Force Plate Setup guide for the force plate (digital) integration. Implementing analog platforms through NI-DAQ devices will only detect the voltage signal, and the force plate features within Motive will not be supported.
- Up to 16 analog channels are supported for up to two NI-DAQ device. If you wish to use higher channel counts, please contact us for more details.
- The OptiHub is not supported for synchronization at this time. Integration into USB-camera systems using the OptiHub has not been tested. Note that the OptiHub does not support generating clock signal, and for this reason, precise synchronization of NI-DAQ devices cannot be achieved and the devices will need to operate in Free Fun mode.
Motive supports PCI and USB data acquisition devices from National Instruments. A list of supported models can be found in the supported devices section. For device specific connections, refer to respective NI User's Guide. For general instructions on setting up the mocap system, refer to the Hardware Setup pages.
Note: When a new device is connected to the system, you must re-start Motive to instantiate it.
USB NI-DAQ Device Wiring Setup
The following diagrams show general wiring setups for connecting and synchronizing a USB NI-DAQ device (screw and BNC terminals) with an OptiTrack Motion Capture system. For precise synchronization, the eSync synchronization hub must be connected to the NI-DAQ device(s).
- Wiring the eSync and the NI-DAQ device: Connect one of the output ports of the eSync into an external sample clock supported digital input terminal of the NI-DAQ device. For screw input terminals, ground signal must be separated from the BNC output of the eSync and relayed into a digital ground terminal.
- Wiring analog devices with the NI-DAQ device: Connect the output port of the analog device(s) into one of the analog input channels of the NI-DAQ device. For screw terminals, a corresponding ground signal needs to be connected to an analog ground channel. For BNC terminals, wiring the ground signal is not necessary, but the input ports should be configured to either FS (Floating Source) or GS (Ground Source) setting depending on the characteristic of the signal source. For more information on connecting peripheral devices into an NI-DAQ device, visit NI support.
- Screw Terminal Device Cabling
- BNC Terminal Cabling
Sample Clock Support
OptiTrack mocap systems use the eSync to provide highly accurate synchronizations. The eSync will be configured to output internal clock signals, and it can be used as the master reference clock which other devices can synchronize to. In order to utilize the clock signal, NI-DAQ device(s) with support for external sample clock must be used. When using devices without the sample clock support, they will not be able to reference the clock signal and the device will have to operate in the free run mode, which may offset the synchronization by few frames.
External Sample Clock Supported NI-DAQ Models:
- X Series: (e.g. PCIe 6320, USB 63XX Series)
- Bus-Powered M Series: ( e.g. USB 6210)
- M Series: (e.g. USB 6221, PCI 6220)
- Non-USB B Series: (e.g. PCI-6010)
External Sample Clock NOT Supported NI-DAQ Models:
- Low cost USB Series (e.g. USB-6002)
Supported National Instruments Devices
Below is the list of NI-DAQ device models that are supported with Motive. For best compatibility, use the recommended models or verified models since they are most tested and approved to work with Motive. Unverified models should work as well, but their integration is not verified yet. For precise synchronization, use the NI-DAQ device model that supports the External Sample Clock.
NaturalPoint Recommended Devices
- USB-63XX X-Series
- USB-6341, USB-6351, USB-6361
|Device Type||Model Number|
|(Low Cost) USB Basic Series||NI 6000, NI 6001, NI 6002, NI 6003, NI 6008, NI 6009|
|E Series||NI 6023E, NI 6024E*, NI 6025E, NI 6030E, NI 6031E, NI 6032E/33E/34E/35E, NI 6036E*, NI 6040E, NI 6052E, NI 6062E*, NI 6070E, NI 6071E, NI PCI-MIO-16E-1, NI PCI-MIO-16E-4, NI PCI-MIO-16XE-10, NI PCI-MIO-16XE-50|
|M Series||NI 6210/11/12/15/16/18, NI 6220, NI 6221, NI 6224, NI 6225, NI 6229, NI 6230/32/33/36/38/39, NI 6250, NI 6251, NI 6254, NI 6255, NI 6259, NI 6280, NI 6281, NI 6284, NI 6289|
|X Series||NI 6320, NI 6321, NI 6323, NI 6341, NI 6343, NI 6345, NI 6351, NI 6353, NI 6355, NI 6356, NI 6358, NI 6361, NI 6363, NI 6365NI 6366, NI 6368, NI 6375|
|S Series||Simultaneous Sampling: NI 6110, NI 6111, NI 6115, NI 6120, NI 6122, NI 6123, NI 6124, NI 6132, NI 6133, NI 6143, NI 6154|
|SC Express||Signal Conditioning: NI 4300, NI 4302, NI 4303, NI 4304, NI 4305, NI 4322, NI 4330, NI 4331, NI 4339, NI 4353, NI 4357|
|DSA Series||Sound and Vibration: NI 4431, NI 4432, NI 4461, NI 4462, NI 4463, NI 4464, NI 4472/B, NI 4474, NI 4492, NI 4495, NI 4496, NI 4497, NI 4498, NI 4499, NI 4610|
|CompactDAQ||Platform to be used with I/O Modules: Supported|
|I/O Modules to be paired with Chassis: NI 92xx, NI 94xx|
|NI MyDAQ||Educational: NI MyDAQ|
For Motive to communicate with NI-DAQ devices, the OptiTrack Peripheral Modules must be installed along with Motive and NI-DAQ device drivers. The OptiTrack Peripherals Module is a software plugin package that bundles and installs required drivers and plugin DLLs for integrating external devices, including NI-DAQ devices and force plates (AMTI and Bertec), into Motive. The following section describes the steps to integrate NI-DAQ device(s) within Motive.
1. Install the OptiTrack Peripherals Module (OPM). The OptiTrack Peripherals Module (OPM) installs all the necessary Motive device plugins. During the Motive installation process (1.10 and above), a list of program features will be shown in the Custom Setup section. Here, change the setting for the OptiTrack Peripherals Module, as shown in the below image, so that the module is installed along with Motive Files.
2. Install the NI-DAQ device drivers. After agreeing to install the OPM, the installer will ask to install NI-DAQmx 15.1.1 driver. You will need to install this driver for MS Windows to recognize the connected NI-DAQ devices. Press Yes and the NI-DAQmx installation will be initiated. Follow the corresponding installation process to set up the driver.
3. Check device connection. Ensure the NI-DAQ device is powered and detected by MS Windows. For USB DAQ devices, you could also use the installed NI Device Monitor to confirm and monitor the connection. The NI Device Monitor can be accessed from the Windows taskbar tray when a USB DAQ device is connected.
4. Launch Motive. In the Devices Pane, all of the connected NI-DAQ devices will be listed along with respective analog input channels (up to 16) within the Devices group.
5. Verify device operation. Once the NI-DAQ device is recognized properly, you will be able to observe the live sampled signal in the 'Scope' view from the Timeline Pane when the inputted channel is enabled and selected in the Device pane.
a. Device Pane: Select an NI-DAQ channel with an active signal.
b. Device Pane: Toggle the NI-DAQ device to begin sampling.
c. Device Pane: Select the active channel.
d. Timeline Pane: Show the 'Scope' View.
6. Zero the DAQ device, if necessary. Signals from an NI-DAQ device and its channels can be zeroed by right-clicking on an NI-DAQ device from the Devices pane, and selecting Zero. Doing this will zero all of the enabled channels for the selected NI-DAQ device, and the existing signals (i.e. signal noise) will be subtracted to zero the base signal.
NI-DAQ Device Property Reference
Now that the device is recognized by Motive, you can select and configure the device and its channels under the Devices pane. Up to 16 analog channels of each device will be listed. For better identification of the channels, you can also rename them in the Devices panel to more descriptive names; such as the signal types or name of the connected device.
NI-DAQ Device Properties
Record Trigger: This setting determines how the recording of the selected NI-DAQ device will be triggered. Setting it to True will use hardware data packets to trigger the record start frame. Setting it to False will trigger the recording when Motive starts capturing data.
Use External Clock: Sets whether an external clock signal is used to sync the devices. The custom synchronization setting must be configured first before configuring this.
- True: Setting this to true will configure the selected NI-DAQ device use external sample clock to control its sampling. The NI-DAQ board must be connected to an external clock output of the eSync on one of its digital input terminals. The acquisition rate will be disabled since the rate is configured to be controlled by the external clock.
- False: NI-DAQ board will collect samples in 'Free Run' mode at the assigned Acquisition Rate.
Acquisition Rate: When the Use External Clock setting is set to False, acquisition rate for NI-DAQ device(s) can be set individually in the Devices pane. You can modify the multiplier to change the acquisition rate to multiples (up to X16) of the camera frame rate. This sets the acquisition rate of the NI-DAQ devices when synchronizing without an external clock signal from the eSync. In this case, the devices will be running at the Free Run mode, and the NI-DAQ device(s) and the cameras will be triggered simultaneously but they will capture at their own sampling rate. Synchronization offsets will be introduced when using the free run mode.
NIDAQ External Clock Terminal: Name of the NI-DAQ digital I/O terminal that is connected to the external clock (TTL) signal.
NI-DAQ Device Channel Properties
Depending on the model, NI-DAQ devices may have different sets of allowable input types and voltage ranges for their analog channels. Refer to your NI-DAQ device User's Guide for detailed information about supported signal types and voltage ranges.
Min Voltage: Configure the terminal's minimum voltage range (Default: -10 volts)
Max Voltage: Configure the terminal's maximum voltage range (Default: +10 volts)
Terminal Type: Configures the measurement mode of the selected terminal. In general, analog input channels with screw terminals use the single-ended measurement system (RSE), and analog input channels with BNC terminals use the differential (Diff) measurement system. For more information on these terminal types, refer to NI documentation.
- Terminal: RSE Referenced single ended. Measurement with respect to ground (e.g. AI_GND) (Default)
- Terminal: NRSE NonReferenced single ended. Measurement with respect to single analog input (e.g. AISENSE)
- Terminal: Diff Differential. Measurement between two inputs (e.g. AI0+, AI0-)
- Terminal: PseudoDiff Differential. Measurement between two inputs and impeded common ground.
Synchronization Configuration: eSync
In order to precisely synchronize the motion capture system with NI-DAQ devices, the eSync must be used. Particularly, the internal clock signal from the eSync is delivered into the NI-DAQ devices and referenced as the external sample clock. To accomplish this, the Sync Input should be set to Internal Clock under the Custom Synchronization settings. Then, the frequency of the internal clock signal can be configured and sent to the NI-DAQ device(s) for synchronizing their sampling rates. The Final Frame Rate of the internal clock signal will set the frame rate of the camera system. After setting the clock frequency, adjust the input divider/multiplier to configure the cameras to the desired frame rate.
Synchronized with the eSync as the master clock, the internal clock rate from the eSync will determine the acquisition rate of the NI-DAQ device. Follow the below steps to setup an NI-DAQ device to use an eSync output as the NI-DAQ external sample clock:
1. Hardware: Connect one of the eSync Output(N) ports into the NI-DAQ digital input terminal.
3. Motive: Synchronization Pane: Select Custom Synchronization from the dropdown menu.
4. Motive: Synchronization Pane: Configure the Sync Source to Internal Clock.
6. Motive: Synchronization Pane: Sync Input (Internal Clock) Set the Clock Freq to desired acquisition rate of the NI-DAQ device(s).
7. Motive: Synchronization Pane: Sync Input (Internal Clock) Adjust the Input Divider to configure the resulting Final Frame Rate which will be used to synchronize the cameras within the system. In order to accurately sample analog signals, the acquisition rate of the NI-DAQ device(s) should not be greater than X16 of the configured camera frame rate; therefore, the Input Divider should not exceed 16.
8. Motive: Synchronization Pane For the eSync output ports connected to the NI-DAQ devices, set the Output(N) Type to Gated Internal Clock. Now the internal clock signal is configured to be delivered into the connected NI-DAQ channel.
9. Motive: Devices Pane: Within the NI-DAQ device property, set the Use External Clock to True. The NI-DAQ sampling rate in the Device Panel should now display the eSync Internal Clock rate.
10. Motive: Devices Pane: Under the NI-DAQ device properties, designate the NI-DAQ External Clock Channel to the NI-DAQ digital input terminal connected in Step 1.
11. Motive: Timeline Pane: Record. The recorded NI-DAQ device samples will be synchronized with the external clock signal.
Synchronization Configuration: OptiHub
The OptiHub is not supported for synchronization at this time.
The following steps describe a general workflow on collecting signals from connected NI-DAQ channels in Motive. Calibrate the camera system before recording if you wish to collect tracking data along with the analog signals.
1. Motive : Device Panel Configure NI-DAQ collection channels properties (terminal type, voltage range).
2. Motive : Device Panel Enable the channels to collect by checking the box next to each channel.
3. Motive : Device Panel Configure NI-DAQ device properties (Acquisition rate, external clock).
4. Motive : Device Panel Enable the NI-DAQ device by checking the box next to the device.
5. Motive : Timeline Tools In the Live mode, scope the timeline to verify the recorded channel/terminal signals appear correctly.
6. Motive : Timeline Tools Start Recording.
Captured analog signals are recorded within the Take file, and they can be played back in Motive. In the Edit Mode, the NI-DAQ device will be shown under the assets in the Project pane, and the corresponding channels will be listed at the bottom of the panel. When you select one of the channels, the recorded signals can be played back in the Timeline pane.
Recorded NI-DAQ data can be exported into C3D files along with the mocap tracking data.
All analog data within the exported C3D files will be logged at the same sampling frequency. If any of the devices is captured at different rates, Motive will automatically resample all of the analog devices to match the sampling rate of the fastest device.
Note that the coordinate system used in Motive (y-up right-handed) may be different from the convention used in the biomechanics analysis software.
Common Biomechanics Convention
Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D, MotionMonitor), the following changes must be made under the custom axis.
- X axis in Motive should be configured to positive X
- Y axis in Motive should be configured to negative Z
- Z axis in Motive should be configured to positive Y.
This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
Note: For Motive 1.10, Y axis must be converted to positive Z instead, this issue has been fixed on Motive 1.10.1 and above.