Making Connections

Instructions for connecting communication & data interfaces (Ethernet or PCIe), the Image_sync synchronization pulse, and interferometer optical fibers to the Axsun Integrated Engine.

Insure the stated environmental requirements are satisfied before connecting and operating your Integrated Engine. Operation of the Integrated Engine outside of the requirements risks performance degradation or damage.

Communication & Data Interfaces

Follow the instructions in this section to physically connect the Axsun Integrated Engine based on your preferred interface (Ethernet or PCIe).

Ethernet Interface
PCIe Interface

Hardware Connections

  • Connect the appropriate end of the DC power “Y-cable” to both the laser driver board and DAQ board. The two connectors are equivalent and non-specific to either board.

  • Connect the AC power cable between the AC/DC adapter and mains power, then connect the DC side of the AC/DC adapter to the appropriate connector on the power “Y-cable” to apply power to the hardware. You will hear the fan come on immediately and see LED lights flashing once the processors boot within approximately 5 seconds.

  • Connect a Cat 5 or Cat 6 Ethernet cable between the DAQ board and an available Gigabit Ethernet network port on the host PC. This connection can be made with the host PC powered on.

Network Adapter Configuration

The host PC’s network adapter which is connected to the DAQ requires no custom (i.e. Axsun-specific) device drivers, but must be configured for static IP addressing rather than DHCP, which is more typical:

  • Open the properties window for the network adapter. Instructions for finding the network adapter properties window are OS-specific and can be found by searching online.

  • Change the IP address (IPv4) of the network adapter to be 192.168.10.1 and the subnet mask to be 255.255.255.0 (which is likely the default). Apply and save the new network adapter settings.

  • Confirm successful reconfiguration of the network adapter and Ethernet connection to the DAQ board by opening a Windows command prompt (or a *nix shell/terminal) and executing the command ping 192.168.10.2

  • If connection is established correctly, the DAQ board (with its static IP address of 192.168.10.2) will respond to the ping request. If the ping fails, follow the recommendations in the DAQ Troubleshooting manual.

To use the DAQ’s PCIe interface when the DAQ board and laser driver board are integrated into a single stack with baseplate and fiber tray, a PCIe 8X (or wider) riser cable [1] must be used to connect the DAQ to the PC’s PCIe bus. If the DAQ is physically separated from the laser driver board, it can be installed directly in an available 8X (or wider) PCIe slot in the PC’s motherboard.

[1] For example: https://www.amazon.com/PCIE-Micro-Express-Flexible-Extension/dp/B00D79EV0G/ or https://www.amazon.com/Tenext-Express-Adapter-Flexible-Extension/dp/B00EY7BW0C

PCIe Hardware Connections (Riser Cable Option)

  • Connect the appropriate end of the DC power “Y-cable” to both the laser driver board and DAQ board. The two connectors are equivalent and non-specific to either board.

  • With the host PC powered off, connect a PCIe riser cable between the PCIe paddle connector on the DAQ board and an available PCIe slot on the PC motherboard, carefully feeding the riser cable through the PC chassis as needed.

  • Connect the AC power cable between the AC/DC adapter and mains power, then connect the DC side of the AC/DC adapter to the appropriate connector on the power “Y-cable” to apply power to the hardware. You will hear the DAQ’s fan come on immediately and see LED lights flashing once the processors boot within approximately 5 seconds.

  • Once the large green LED in the corner of the DAQ is flashing steadily and indicating successful FPGA program loading, then power-on the host PC.

  • Connect 2 USB cables: one between the DAQ board and the host PC and one between the Laser Engine and the host PC. These USB connections provide device functionality accessed by the AxsunOCTControl library.

Hardware Connections (Motherboard Slot Option)

  • With the host PC powered off, plug the DAQ board into an available 8X (or wider) PCIe slot on the PC motherboard, insuring that the DAQ board has appropriate clearance from other boards and cables inside the PC chassis. Install the retention hardware (e.g. screws or clips) which hold the board securely in the PCIe slot.

  • Connect the appropriate end of the DC power “Y-cable” to both the laser driver board and DAQ board power receptacles. The two connectors are equivalent and non-specific to either board.

  • Connect two SATA cables between the laser driver board and the DAQ board. The SATA receptacles nearest to the power supply receptacle on each board must be connected to each other with one SATA cable, and the two SATA receptacles farthest from the power supply receptacle must be connected with the other SATA cable. Double-check that the cables are not crossed into the incorrect receptacle.

  • Connect the AC power cable between the AC/DC adapter and mains power, then connect the DC side of the AC/DC adapter to the appropriate connector on the power “Y-cable” to apply power to the DAQ and laser hardware. You will hear the DAQ’s fan come on immediately and see LED lights flashing once the processors boot within approximately 5 seconds.

  • Once the large green LED in the corner of the DAQ is flashing steadily and indicating successful FPGA program loading, then power-on the host PC.

  • Connect 2 USB cables: one between the DAQ board and the host PC and one between the Laser Engine and the host PC. These USB connections provide device functionality accessed by the AxsunOCTControl library.

PCIe Device Driver Installation

After the DAQ hardware is connected to the host PC via PCIe, some additional driver software installation is necessary. Follow these instructions to install the PCIe device driver and confirm correct installation before proceeding with the instructions in this guide:

Image_sync Synchronization Pulse

NOTE: The Axsun Integrated Engine will operate (in Force Trigger Mode) even if an Image_sync trigger connection is not yet established. You can skip to the next page in this guide to verify correct hardware/software installation of your Axsun Integrated Engine by streaming unsynchronized image data, and return to this section later when connecting your OCT scanner hardware.

It is often important to synchronize the captured and displayed OCT B-scan images with an external scanner that is operating in a periodic fashion (e.g. linear or raster scan, rotational or helical scan, etc.). The component driving the external scanner (e.g. arbitrary waveform generator card, spinning motor, etc.) must generate a digital pulse once per period which is used by the DAQ board to provide this image synchronization. The synchronization pulse is provided to the DAQ on its Image_sync trigger input (rising edge active) and is user-selectable between LVDS or LVCMOS signaling as discussed here.

Connect the synchronization pulse from your external scanner driver to the DAQ using the connectors, pinout, and signal levels described in the below tables:

Connector

Component

Part Number

Mating Connector to the beige 12 pin header

Molex 501646-1200 / Digikey WM6059-ND

22-26 AWG Crimp Terminals

Molex 501647-1000 / Digikey WM6057CT-ND

The DAQ uses the 12-pin version of the Molex connector. The photo shows LVCMOS trigger wires.

LVCMOS Mode

Pin #

TITLE

DESCRIPTION

Pin 3

TRIGGER

single ended trigger with 0.0 V (L) to >2.5 V (H)

Pin 4

GND

LVDS Mode

Pin #

TITLE

DESCRIPTION

Pin 7

TRIGGER +

Differential Trigger with 1.0 V (L) to 1.4 V (H)

Pin 8

TRIGGER-

Differential Trigger with 1.0 V (L) to 1.4 V (H)

Interferometer Fiber Optics

NOTE: The Axsun Integrated Engine will operate before fiber optic connections are made. You can skip to the next page in this guide to verify correct hardware/software installation of your Axsun Integrated Engine by streaming images consisting of only background noise, and return to this section later when connecting your OCT interferometer and scanner hardware.

Before any optical fiber connections are made, always clean and inspect the fiber tips per industry standards.

The accessible optical fibers will be labeled depending on whether your Integrated Engine includes an optional OCT interferometer, and if not, whether the Integrated Engine includes one balanced receiver channel (two matched photodiodes) or two balanced receiver channels (two pairs of matched photodiodes; for polarization diverse detection).

Source & Photodiode Fibers (no interferometer)
Sample & Reference Fibers (optional OCT interferometer)

Connect the fiber labeled "LASER Output" (or "Source") to the input of your OCT interferometer.

Connect the fibers labeled "CH1 A" and CH1 B" (or "Diode1" and "Diode2") to your OCT interferometer outputs for the first balanced receiver channel.

Optionally, connect the fibers labeled "CH2 A" and CH2 B" (or "Diode3" and "Diode4") to your OCT interferometer outputs for the second balanced receiver channel.

Connect the fiber labeled "SAMP" to your OCT sample arm.

Connect the fiber labeled "REF" to your OCT reference arm.

Congratulations! You have physically connected the Axsun Integrated Engine hardware to your host PC. Don't forget to return here later if you skipped optional sections.

The next page in this guide describes the basic Operation of the Integrated Engine to capture and display OCT images in real-time.