OCT Host

version 1.18.0 or later


OCT Host (OCTHost.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.

OCT Host connects to the device using the AxsunOCTControl API and supports communication over USB, RS-232, and Ethernet (depending on the device configuration). Primary functions of OCT Host include:

  • starting and stopping laser emission

  • retrieving status and diagnostic information

  • upgrading device firmware

  • configuring K-clock delay and other default settings

  • operating an optional motorized Variable Delay Line (VDL)

Compatibility Requirements

OCT Host is compatible with 32- and 64-bit versions of Windows OS from Windows XP through Windows 11. 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.


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.

Download your preferred version of OCT Host (.exe) from the Software Downloads page.

NOTE: Azmyth engine users must download and install OCT Host version 2.x. (OCT Host versions 1.x do not support the Azmyth engine.)

Extract the .zip file and then run the setup.exe to begin the installation.

Click on Run to proceed with installation if Windows presents a user access control security warning.

Follow the Axsun OCT Control Installation window by clicking Next.

A device driver installation window will appear. Follow Installation Wizard by clicking Next.

Click on Install, if Windows gives a security warning window.

Once "Installation Complete" is displayed, click Close.

Once the driver status displays "Ready to use". Click Finish.

Using OCT Host

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

Connected Devices Indicator

Axsun devices which are successfully connected to OCT Host will be listed in the lower left corner of the main OCT Host window:

NOTE: The Devices tab provides additional information about connected devices.

Feature Group Tabs

OCT Host features are grouped onto tabs which are arranged horizontally at the top of the main window. The following sections highlight the relevant controls and indicators available on each tab. Some tabs are visible only when certain device types are currently connected (i.e. Laser Engine or DAQ).

Engine Control


  • The engine Serial Number is unique to each engine. This serial number is also printed on a label placed on the engine itself (base plate of standard OEM, outside of EMI shield on Small Form Factor OEM, outside of enclosure on Benchtop)

The serial number of an engine is critical information to give to Axsun Tech Support when initiating a tech support communication. This will allow Tech Support to access all the relevant engineering testing documents that were done specifically on the engine.

  • The System Type can be either Light source or DAQ or Cameralink ADC.

  • The Connection Type can be USB (when a laser board or DAQ board is connected the computer using a USB cable), RS232 (when a laser board or a DAQ board is connected to the RS232 port on the computer), RS232 PASS THROUGH (when it is a integrated engine type having both a DAQ and a laser) or NETWORK.

  • The Firmware displayed on the Engine Control tab is the firmware for the light source.

  • Uptime is the number of milliseconds that the system has been powered on for. This number goes to 0 after a reboot.

  • Laser On Time is the number of seconds that the laser has been in use for the lifetime of the laser on the system.

  • W.L. at start trigger displays the factory set setting: wavelength at start trigger

  • TEC 1 and TEC 2 indicators are:

    • transparent when laser is not initialized

    • red when the TEC is not installed

    • orange when the status of the laser is waiting to get ready

    • yellow when the laser is warming up

    • green when the laser is ready to use.


  • Click on Run to turn the engine ON (output spectrum ON, trigger ON, clock ON)

  • Click on Stop to turn the engine OFF (output spectrum OFF, trigger OFF, clock OFF)

  • Click on Get Status to force an update of the status of the engine

  • Click on Continuous to update the status of the engine every 500 ms

Source current ON/OFF buttons are provided to be used only for troubleshooting purposes as directed Axsun Tech Support.

  • About button gives detailed information about the name, version, build date and process of the OCT Host Application and Control as well as the laser engine board firmware.

    • Engineering Mode is password protected and to be used by Axsun Tech Support only.


Under Devices tab, confirm that OCT Host can detect all the devices present. The devices will be listed under "Connected OCT Devices". The serial number of each device, its type and firmware will be listed.

If there are multiple lasers connected to the same computer, each light source and its serial number will be listed under the Devices tab, OCT Engine section. OCT Host can control one engine at a time, therefore:

  • click on the desired engine to select it

  • click on Connect To This OCT Engine

  • confirm that the selected engine type is listed in the connected boards.

Clock Delay

To edit the clock delay, go to Engine Control tab and double click on the text box displaying the clock delay value. The clock delay is set between the minimum delay, 28.285 nsec and the maximum delay, 64.58 nsec in 0.575 nsec intervals. For example, a value of 0 is 28.3 ns, and value of 10 is 34 ns.

Switching Configurations

Some engines can be configured with up to 4 different configurations (different speeds, dummy clocks ON/OFF... ). For these engines a Switch Configuration button and drop down menu for configurations options are displayed under the Engine Control tab.

Switching configurations can be done while the laser emission is ON.

To switch configurations, follow steps 1 through 4 below:

After a laser is powered cycled, configuration A is always the default configurations that the laser come back to even if it was powered off while on a different configurations.


Every engine ships with the most updated firmware that is best for its operation.

In some cases, Tech Support might recommend upgrading the firmware per the instructions.

VDL Motor

OCT Host can be used to operate an optional motorized Variable Delay Line (VDL) according to these instructions.


  • For single reading of diagnostics:

    1. Press Read to force OCT Host to update the most recent values of signals

    2. Press Copy To Clipboard to copy then paste the diagnostics data

    3. Press Save Single Reading To File... to save the diagnostics data

  • For continuous reading of diagnostics:

    1. Press Continuous to start a continuous update of the signals. The button will then display Stop Continuous

    2. Press Save Continuous to File... to save a continuous diagnostics data. The button will then display Stop Continuous Save to File

    3. Name the Continuous file and save it

    4. Press Stop Continuous Save to File... to stop recording continuous diagnostics

    5. Press Stop Continuous when done

Engine TEC

Pressing Get TEC 1 Status / Get TEC 2 Status return the values of each parameter related to the thermoelectric cooler (TEC). This information is important for troubleshooting. It can be saved using Save Data to File... and shared with Axsun Tech Support.

Clicking on Reset TEC 1 / Get TEC 2 Status resets TEC 1 / 2 o the state where it was powered on. This is useful to recover from an error state. If that does not return TEC 1 /2 status seen under Engine Control to GREEN, contact Axsun Tech Support.


The Errors tab displays important information that can be shared with Axsun Tech Support to diagnose some problems remotely if the laser engine is not working properly.


This tab can be used to interact with the FPGA DAQ data.

DAQ FPGA Registers

This tab can be used to get the FPGA register values and to set specific decimal values to registers.

DAQ Configuration

  1. Press Request from Device to read the current FPGA default configuration script into the table shown on the right of the tab

  2. Save the script to a *.csv file by pressing Save to File…. Also save a backup copy of the original script file in case reverting is necessary!

  3. Manipulate register-number / register value combinations as needed in Excel or a text/spreadsheet editor and save the file. Insure that register values are in the correct representation (decimal or hexadecimal – usually Excel will default to decimal).

  4. Press Load from File… to read the modified configuration script into the table shown on the left of the tab

  5. Press Send to Device to write the modified configuration script to the board’s non-volatile memory.

Do NOT change the default values of any register for which you are not instructed here or by Axsun Tech Support.

Quitting the OCT Host

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

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