Making Connections

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

WARNING: 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 hardware damage.

WARNING: All electrical signal connections and disconnections must be made with the device in a powered-off state.

Communication & Data Interfaces

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

Ethernet Interface (data & control)

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.

PCIe (data) & USB (control) Interfaces

Hardware Connections

• With the host PC powered off, plug the DAQ board into an available x8 (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 ends 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 and wait for the OS to load.

• Connect 2 USB cables: one between the DAQ board and the host PC and one between the Laser Engine and the host PC.

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 install software and then 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. This synchronization pulse is provided to the DAQ on its Image_sync trigger input (rising edge active).

• Connect the synchronization pulse from your electrical scanner driver to the DAQ using your custom cable terminated with the following electrical connector:

	Molex Part Number	Digi-Key Part Number
Mating Connector (12 pin)	Molex 501646-1200	WM6059-ND
22-26 AWG Crimp Terminals	Molex 501647-1000	WM6057CT-ND

• The external Image_sync trigger input is user-selectable between either LVDS or LVCMOS signaling as discussed here. Use the following pinouts for your preferred signaling type:

	Pins	Signal Levels
2.5 V LVCMOS mode	Pin 3: TRIG Pin 4: GND	Single-ended trigger with 0.0 V (L) to >2.5 V (H)
LVDS mode	Pin 7: TRIG+ Pin 8: TRIG-	Differential trigger with 1.0 V (L) to 1.4 V (H)

Pins for LVCMOS (red) or LVDS (blue) shown on the Molex connector schematic (left) and a photograph of the mated connector with LVCMOS trigger wires (right).

NOTE: The Molex schematic above shows a 20-pin connector (generic for the iGrid series of connectors). The actual Image_sync connector uses the 12-pin version as shown in the photograph.

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 install software and then verify correct hardware & software installation of your Axsun Integrated Engine by streaming live images consisting of only background noise, and return to this section later when connecting your OCT interferometer and scanner hardware.

WARNING: 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 integrated 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 e.g. for polarization diverse detection).

Source & Photodiode Fibers (external 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.

Sample & Reference Fibers (optional OCT interferometer)

• 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 Software Installation needed to operate the Axsun Integrated Engine with the connected host computer.