Main Page → NI-DAQ Setup
National Instruments data acquisition (NI-DAQ) devices can be integrated with 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. For a list of supported models, please refer to the Supported NI-DAQ Models section of this page.
For instructions specific to 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 Peripheral Device module to register, initialize, and record using the connected DAQ device(s). When properly configured, voltage signals of up to 32 analog channels per each connected NI-DAQ device can be sampled along with the tracking data. Recorded analog data can be saved into the Take (.TAK) file and the data can be exported into C3D and CSV files for further analysis.
The eSync synchronization hub must be used for precisely aligning recorded signals with tracking data. NI-DAQ device(s) synchronizes with a camera system by syncing with the internal clock signal outputted from the eSync. For this reason, NI-DAQ device(s) have to support the clock signal input and must connect to the camera system through the eSync.
- OptiTrack Motion Capture System
- The eSync synchronization hub
- Motive 1.10 and above with a valid software license.
- OptiTrack Peripheral Device module.
- NI-DAQ device(s): PCI or USB. See more at Supported Devices.
- Third party analog devices.
- The NI-DAQ functionalities are not supported with the use of the Motive API.
- For integration of digital force plates, follow the Force Plate Setup guide. Analog platforms can be integrated through a NI-DAQ, but only raw voltage signals can be detected and the force plate features within Motive will not be supported.
- Up to 32 analog channels are supported for each NI-DAQ device. If you wish to use higher channel counts, please contact us for more details.
- Synchronization with the OptiHub and a USB camera system can only be accomplished by trigger sync only.
- 1 Hardware Setup
- 2 Software Setup
- 3 NI-DAQ Device Property Reference
- 4 Synchronization Configuration: eSync
- 5 Synchronization Configuration: OptiHub
- 6 Collecting Data
- 7 Data Playback
- 8 Analog Data Export
- 9 Troubleshooting
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 general instructions on setting up the mocap system, refer to the Hardware Setup pages.
Hot plugging is not supported with the integration. 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 wiring setups for connecting and synchronizing USB NI-DAQ devices with Prime series motion capture systems:
- Wiring the eSync and the NI-DAQ device: Connect one of the output ports of the eSync into a digital input terminal of the NI-DAQ device that supports external sample clock inputs. For screw input terminals, ground signals 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 of an 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 synchronization. In Motive, the eSync will be configured to output internal clock signals and used as the master reference clock which other devices can synchronize to. In order to utilize the clock signal, a NI-DAQ device(s) that supports external sample clock input must be used. When using DAQ devices without the sample clock support, they will not be able to reference the clock signal. In this case, the device will have to sync at the start of the recording and operate in the Free Run mode with independent acquisition rate which may result in synchronization drift over time.
NI-DAQ models supporting external sample clock:
- 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)
NI-DAQ models NOT supporting external sample clock:
- 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 has not beenbeen verified yet.
NaturalPoint Recommended Devices
- USB-63XX X-Series
- USB-6341, USB-6351, USB-6361
- USB 6281 (M Series)
|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|
- Integration of the CompactDAQ is also supported.
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). The following section describes the steps to integrate NI-DAQ device(s) within Motive.
1. Install the Peripherals Device module
- During the Motive installation process, optional program features will be listed in the Custom Setup section. Here, change the setting for the Peripherals Device, as shown in the below image, so that the module is installed along with Motive.
2. Install the NI-DAQ device drivers
- After agreeing to install the Peripheral Device, 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 to initiate the NI-DAQmx installation and follow the instructions to set up the driver.
Installation Note: For integration into Motive, the NI-DAQmx 15.1.1 or later runtime driver must be installed. If you are already using an older version of the NI-DAQmx runtime and Motive is having problems recognizing the connected device, update the driver or uninstall and re-install the packaged version of the driver before contacting Support. In Motive, you can inspect device connection status via the Status Log panel which can be accessed under the View tab in Motive.
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 software 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 32) under the Data Acquisition group.
5. Verify device operation
Once the NI-DAQ device is recognized properly, you will be able to observe the real-time signal on the Graph View pane.
First, make sure the NI-DAQ device and its operating analog input channels are enabled under the Devices pane. Then, open the Graph View pane and create a custom layout for monitoring live-analog data; create a new layout, right-click on the graphs, and select the device channel you wish to plot. Then, open the graph editor () and make sure View Style is set to Live under the Visuals tab. Configured analog channels will be plotted on the graphs.
a. Device Pane: Select a 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. Graph Pane: Show the 'Scope' View.
6. Zero the DAQ device
- Detected voltage signals from a NI-DAQ input channels can be zeroed. Right-click on a NI-DAQ device from the Devices pane and click Zero. Doing this will zero all of the enabled channels for the selected NI-DAQ device.
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. Analog channels of each device will be listed. When a data acquisition device or an analog channel is selected, their respective properties will be displayed on the Properties pane.
NI-DAQ Device Properties
- 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 integrated. For precise synchronization using the internal clock signal sync, set this to true.
- True: Setting this to true will configure the selected NI-DAQ device to synchronize with an inputted external sample clock signal. The NI-DAQ 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 signal.
- False: NI-DAQ board will collect samples in 'Free Run' mode at the assigned 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 drift will be introduced over time when using the free run mode.
NIDAQ External Clock Terminal
- Name of the NI-DAQ digital I/O terminal that the external clock (TTL) signal is inputted to.
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.
- (Default: -10 volts) Configure the terminal's minimum voltage range.
- (Default: +10 volts) Configure the terminal's maximum voltage range.
- 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. The internal clock signal is generated from the eSync and outputted to the NI-DAQ device(s) for precisely synchronizing two systems together. This way, all the data samples are synchronized per-frame basis, and this approach is referred as the synchronization through external sample clock signal.
To configure this, set the Sync Input to Internal Clock under the eSync properties so that it outputs the clock signal. Here, the clock frequency of the internal clock signal will basically set the sampling rate of the NI-DAQ device(s). Then, the input divider/multiplier can be adjusted to achieve desired camera frame rate, and the final camera system framerate will be calculated and indicated under the eSync properties and in the Devices pane. The following steps summarize the external sample clock sync setup steps:
1. [Hardware]: Connect one of the eSync Output(N) ports into the NI-DAQ digital input terminal.
4. [Motive: Properties pane (eSync)]: Configure the Sync Source to Internal Clock.
5. [Motive: Properties pane (eSync)] Set the Clock Freq to desired acquisition rate of the NI-DAQ device(s).
6. [Motive: Properties pane (eSync)] Adjust the Input Divider/Multiplier to set the final frame rate for the camera 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. In other words, the Input Divider should not exceed 16. The final camera system frame rate will always be displayed under the Devices pane and the eSync properties.
7. [Motive: Properties pane (eSync)] 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 outputted through the output(N) port into the connected NI-DAQ channel.
9. [Motive: Properties pane (NI-DAQ)] Within the NI-DAQ device property, set the Use External Clock to True. At this point, sampling rate of the NI-DAQ device in the Device Panel should be set to the same frequency as the internal clock signal configured for the eSync.
10. [Motive: Properties pane (NI-DAQ)] 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: Control Panel] 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 OptiHub does not feature clock signals, and for this reason, precise synchronization of NI-DAQ devices cannot be achieved.
The following steps describe a general workflow on collecting signals from connected NI-DAQ channels in Motive. Make sure the camera system is calibrated before recording if you wish to collect tracking data along with the analog signals.
2. [Motive : Properties pane] Configure NI-DAQ collection channels properties (terminal type, voltage range) as described in the channel properties section above.
3. [Motive : Device pane] Enable the channels to collect by checking the box next to each channel.
4. [Motive : Properties pane] Now, select the NI-DAQ device in the Devices pane, and configure device properties (Acquisition rate, external clock). Set the Use External Clock to true for synchronization through the eSync.
5. [Motive : Devices pane] Enable the NI-DAQ device by checking the box next to the device.
6. [Motive : Graph View] In Live mode, scope the timeline to verify the recorded channel/terminal signals appear correctly.
7. [Motive : Control Deck] Start Recording.
Captured analog signals are recorded within the Take file and they can be played back in Motive. When in Edit mode, the integrated NI-DAQ device will be shown under the Assets pane, and its Analog measurements can be plotted on the Graph View pane. You will need to create a custom graph layout and enable plotting of analog channels:
Graph Layout with Analog Plots
Analog Data Export
Recorded NI-DAQ analog channel data can be exported into C3D and CSV files along with the mocap tracking data. You can just follow the normal the tracking data export steps, and if the analog data exists in the TAK, they will also be exported.
C3D Export: Both mocap data and the analog data will be exported onto a same C3D file. Please note that all of the analog data within the exported C3D files will be logged at the same sampling frequency. If any of the devices are captured at different rates, Motive will automatically resample all of the analog devices to match the sampling rate of the fastest device. More on C3D files: https://www.c3d.org/
CSV Export: When exporting tracking data into CSV, additional CSV files will be exported for each of the NI-DAQ devices in a Take. Each of the exported CSV files will contain basic properties and settings at its header, including device information and sample counts. The voltage amplitude of each analog channel will be listed. Also, mocap frame rate to device sampling ratio is included since analog data is usually sampled at higher sampling rates.
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), 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).