Hardware Control Tool


The Hardware Control Tool (AxsunHardwareControlTool.exe) is a software interface for users of Axsun SS-OCT Laser Engine and DAQ products. It provides a tab- and button-based GUI to easily interact with a variety of features provided by Axsun Laser Engine and DAQ devices.

The Hardware Control Tool connects to the device using the AxsunOCTControl API or AxsunOCTControl_LW API and supports communication over USB, RS-232, and Ethernet (depending on the device configuration).

The Hardware Control Tool is recommended for users of the Axsun Integrated Engine with Ethernet / PCIe DAQ. Its primary functions include:

  • configuring high-level Ethernet/PCIe DAQ features such as:

    • apodization window function and spectral shaping

    • dispersion compensation

    • pre-FFT and post-FFT background subtraction

    • processing pipeline bypass modes for raw data access

  • starting and stopping laser emission

  • configuring K-clock delay and other power-on default settings

  • operating an optional motorized Variable Delay Line (VDL)

Compatibility Requirements

The Hardware Control Tool is compatible with 64-bit versions of Windows OS from Windows 7 through Windows 10. There are no special hardware requirements other than an available USB port (or RS-232 serial port) for each Axsun device, or a 1Gbps Ethernet port for connecting to the Ethernet DAQ via network interface.

Relationship to OCT Host

Both OCT Host and the Hardware Control Tool provide a command & messaging interface to Axsun hardware devices. Although they have some overlapping functionality, OCT Host is laser-centric and is intended to support debugging, field-service, and maintenance tasks, whereas the Hardware Control Tool is designed for users of the Axsun Ethernet/PCIe DAQ board and enables high-level interaction with several advanced DAQ board features.

WARNING: Do not open OCT Host and the Hardware Control Tool concurrently. Ethernet DAQ hardware will accept only one network connection from a library instance at a time.


To install the Hardware Control Tool and its dependencies, download the most recent version from www.axsun.com/downloads and follow the complete software installation instructions for the Axsun Integrated Engine.

Using the Hardware Control Tool

NOTE: Your screen may not match exactly with the screen representations shown in this guide, depending on your system configuration and installed firmware/software versions.

Physically connect and power-up the Axsun devices. Launch AxsunHardwareControlTool.exe and wait for the main window to open:

Axsun Hardware Control Tool main window

Connected Devices

Axsun devices which are successfully connected to the Hardware Control Tool will be listed along with their firmware (FW) version, FPGA version (DAQ board only), and interface type (Ethernet network, USB, or RS-232) in the upper left corner of the main Hardware Control Tool window:

Laser Engine and Ethernet DAQ devices connected to the Hardware Control Tool

Laser Emission Controls & Indicator, Ethernet DAQ Imaging Mode Controls

LASER: ON and LASER: OFF buttons control the emission state of the laser.

EDAQ: LIVE, EDAQ: OFF, and EDAQ: RECORD buttons control the imaging modes of the Ethernet DAQ. Refer to Controlling Operational Modes for more details on the behavior of these buttons.

Laser emission status is shown by the green indicator next to the laser emission control buttons.

Laser emission is ON as shown by the bright green indicator color.

Feature Group Tabs

Additional Hardware Control Tool features are grouped onto tabs which are arranged horizontally under the Connected Devices indicator. The following sections highlight the relevant controls and indicators available on each tab. Descriptions of functionality are often written near the relevant control directly on the tab. Additional information can be found in the documentation for the underlying functions in the AxsunOCTControl or AxsunOCTControl_LW APIs.


Control or Indicator Name

AxsunOCTControl_LW Functions

AxsunOCTControl Functions




VDL Position (mm)



K-Clock Delay (ns)



DAQ Timing Settings (Clock)


WriteDAQRegisterBit() as described in Advanced DAQ Features

DAQ Timing Settings (Sweep Trigger)


WriteDAQRegisterBit() as described in Advanced DAQ Features

DAQ Timing Settings (Image_sync)


WriteDAQRegisterBit() as described in Advanced DAQ Features

Listen for Network Devices


StartNetworkControlInterface() and StopNetworkControlInterface()

  • The Listen for Network Devices toggle switch selects whether or not the Hardware Control Tool application will listen for (and establish & maintain a control connection with) an Ethernet DAQ present on the host computer's network interface. If this switch is OFF, control connections require the USB interface. Disabling the network-based control interface is for installations wherein an Ethernet DAQ is connected via Ethernet for high-bandwidth data capture only (using AxsunOCTCapture) but USB is the desired control interface for low-bandwidth command and status messaging.

  • The Use AxsunOCTControl_LW (requires restart) toggle switch selects whether the Hardware Control Tool application will load the AxsunOCTControl_LW library (switch = ON) or the AxsunOCTControl library (switch = OFF) the next time it is launched. The currently-loaded library and version is shown in the Library: indicator.

The Miscellaneous tab

Pipeline Modes & Subsampling

The Pipeline Modes & Subsampling tab selects the location from which captured data is transmitted to the host interface from within the DAQ's FPGA-based SS-OCT image processing pipeline. Data is available in raw format directly from the ADC, in fully-processed intensity SS-OCT image format, or at intermediate steps within the processing pipeline. Depending on the connected data capture interface (i.e. Ethernet or PCIe), A-line Subsampling may be required to prevent saturating the interface's data bandwidth. See Advanced DAQ Features for more information.

Control or Indicator Name

AxsunOCTControl_LW Functions

AxsunOCTControl Functions

Subsampling Factor (1 of N)


SetFPGARegister()as described in Advanced DAQ Features



SetFPGARegister()as described in Advanced DAQ Features



SetFPGARegister()as described in Advanced DAQ Features

  • Buttons to select a DAQ Pipeline Bypass Mode are oriented horizonatally in a left-to-right fashion matching the SS-OCT data processing block diagram implemented in the FPGA. These buttons configure the DAQ to transmit captured data to the host interface directly from the output of the selected processing block with all upstream blocks to the left enabled, and all downstream blocks to the right 'bypassed'. BLUE buttons select Channel 1 (H) only, RED buttons select Channel 2 (V) only, and PURPLE buttons select the vector sum of Channels 1 and 2 (i.e. polarization diverse mode).

  • Choose A-line Subsampling approach is a menu which configures the Hardware Control Tool to automatically program a A-Line Subsampling behavior specific to each subsequently selected Pipeline Bypass Mode:

    • Set Manually does not change subsampling. Use the Subsampling Factor (1 of N) control.

    • No Subsampling turns subsampling off resulting in maximum bandwidth.

    • Automatic (Max GigE BW) sets subsampling appropriate for the maximum bandwidth supported by the Gigabit Ethernet interface.

    • Automatic (Max PCIe BW) sets subsampling appropriate for the maximum bandwidth supported by the PCIe interface.

    • Automatic (Aggressive) keeps bandwidth considerably under the upper limit for all interfaces.

  • Configure Background and Configure Window buttons are simple links to the Background Subtraction and Windowing & Dispersion Compensation tabs, respectively. Use these to configure the FPGA's OCT image processing features.

The Pipeline Modes & Subsampling tab

Windowing & Dispersion Compensation

(details coming soon)

The Windowing & Dispersion Compensation tab

Background Subtraction

(details coming soon)

FPGA Registers

(details coming soon)

The FPGA Registers tab

Board Settings & Defaults

(details coming soon)

The Board Settings & Defaults tab

Test Vectors

The Axsun Ethernet/PCIe DAQ board can operate in an emulation mode wherein an arbitrary waveform can be loaded and then repeatedly substituted for sampled ADC data at the input to the imaging pipeline. The downstream FPGA processing and transmission of data to a host PC behaves equivalently to the standard (non-emulated) mode of operation.

This feature is convenient if optically-generated OCT signals or k-clocks are unavailable to the DAQ (e.g. no laser or interferometer connected). Data bandwidth, buffering mechanics, control interfaces, and API accesses are unchanged in emulation mode, and thus wholly relevant for purposes of software development/integration, although the generated image is static and uninteresting.

The waveform is loaded as a "test vector" of length 2048 samples with 12-bits of dynamic range, just like the actual analog-to-digital converters. The Hardware Control Tool's Test Vectors tab provides an interface for selecting among several typical waveform types and parameters. Press the UPDATE DAQ button to load the desired waveform into the DAQ's memory, and press the TEST VECTOR ON or TEST VECTOR OFF buttons to toggle between standard and emulated modes.

The Test Vectors tab

Without a laser connected, the DAQ will also need to be configured to sample and trigger off of internal clock sources (500 MS/s sample clock, 100 kHz sweep trigger). Configure these settings in the DAQ Timing Settings section of the Miscellaneous tab:

DAQ Timing Settings on the Miscellaneous tab

Once Test Vectors and DAQ Timing Settings are configured as desired, use the standard GUI or API controls for changing operational modes and pipeline modes of the DAQ.

Quitting the Hardware Control Tool

To exit the Hardware Control Tool and drop existing connections to Axsun devices, simply close the main window by clicking the "x" icon in the upper right corner.