RedShirtImaging, LLC. NeuroPlex Photodiode Array Imaging System
Installation & Testing Procedures For NeuroPDA

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Propagating population signal from the turtle visual cortex. Provided by Jim Prechtl, Larry Cohen and David Kleinfeld, Yale University and UCSD.

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RedShirtImaging, LLC.
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This shipment contains 5 boxes. The content is indicated on the outside of each box:
  1. post amp-MUX module
  2. Diode array
  3. Power module
  4. Control panel
  5. Computer
NeuroPlex System Diagram
During unpacking, inspect the packing carton and document for any external damages. This information might be needed for insurance purposes. If external damage is identified, unpack the box and inspect for damage to the contents. This shipment is fully insured, write a detailed note describing the shipping damages. If many amplifier cards in the post Amp/MUX module are dislocated, the module may have undergone excessive G which may cause damage to the amplifier cards. Notify the shipper if damages occurred. Since the damages may be found later, contact RedShirtImaging immediately if hardware damage is identified. Be careful to unpack the contents from the correct side of the box. The control panel (#4) needs to be unpacked with caution. There may be wires near the edge of the panel. Make sure to cut the packing tape from the front side.
NEVER turn off the computer power when the diode array system is powered. In the provided DELL PC, software shut down will turn off the computer power.


When turning the system on or off, set the Pre-Amp Gain at "LOW", set the Post-Amp Gain at "1" and the HP Filter at "AC2".


DO NOT TOUCH THE FIBER OPTICS APERTURE or THE FIBERS INSIDE THE DIODE ARRAY. DO NOT USE alcohol or any organic solvent to clean the fiber aperture.


DO NOT mount the diode array on the microscope with only the "C" mount. ADDITIONAL SUPPORT IS NECESSARY.


UNPLUG THE POWER SUPPLY before opening its case or putting your hands inside.


Power Up the Computer
Open the computer case and inspect for any loosened cards. Often the PCI video card and the MicroStar A/D card become ajar during shipping. If that happens, take the loosened card out and securely plug it back into the slot. Run NeuroPlex following the software manual. You should be able to take data and display them. The IDL hardware key is included in the computer package.

Shut down the computer (power off). Plug in the WuTech Output-Amp Control panel to the computer using the 25-pin male "D" connector adjacent to the A/D connector at the back of the computer. Connect the panel to the computer with the cable supplied. Power-up the computer and take data again. Some LED indicators on the panel should blink according to the data acquisition sequence. This indicates the computer, the program, the A/D card, and the Output-Control Panel are working properly. Shut down the computer for the next step.
Power Up The Post Amp Module
Remove the REAR panel (the panel that does not have BNC connectors and LED lights) of the WuTech Post Amp-MUX model by loosening the four thumb-nuts (be sure to keep the nuts and four Nylon spacers). Remove the packing material underneath the panel. Identify the two short flat cables (one has 40 leads and the other has 10 leads) which connect to the A/D card in the PC. Note: The male connectors on the A/D card (computer side) do not have keys. Therefore it is possible to plug the cable in upside-down. Please check the labels on the cable for correct orientation. Connect the cable for the control panel (labeled) to the control panel.

Power-up the computer. The two LEDs on the FRONT panel of the Post Amp module, +15V and -15V under "Power Supply- computer power" should be on, indicating that the MUX cards and A/D cards are connected properly.
Use a signal generator to supply a 100 Hz, 5V p ~ p square wave to the BNC plug #1 on the front panel of the PostAmp Module. Take data again and examine the output of channel 466 (Using the Multiple Display Mode for the trace window). You should see a square wave of 100Hz 5V on that detector. This indicates the MUX cards and A/D are working properly.
Power Up The Whole System
1.   Before plugging in the WuTech power supply, use an Ohm meter to measure the resistance between the power housing and ground to make sure the power housing is grounded. If the power supply is mounted on a rack, make sure the power supply housing has a very good contact to the rack and the rack has a very good ground line.
2.   Without connecting to another part of the system, turn the power supply on. All of the LED indicators on the front panel should be on, indicating that the voltages are supplied. Measure the output voltages on the large output connector with a volt-meter. Make sure there are four supply voltages: +/- 15V and +/-7.2V to 8V. After the measurement turn off the power for a few seconds and turn it on and measure the output voltages again. Repeat this procedure three times. This will ensure that the output voltages did not change during shipment and the power supply is safe for the device.
3.   If the line voltage is 220V, a special precaution is needed. In the factory the power supply was tested under 110V and then set to 220V input before shipping. Power under 220V was never tested. If the conversion was wrong, the power supply is likely to hold many minutes before it burns. During this time the output voltages would be correct. Thus it is extremely important to do the following test at a 220V area -- leave the power supply on for AT LEAST 10 MIN before connecting to the rest of the system. During this period if any abnormality occurs, such as a burned fuse, smoke or noise in the housing, unplug the plug on the wall and send the power supply back. If after ten minutes, there is no smoke and all the lights on the power supply are on, you can conduct the normal power-up test described above.
4.   Turn off the power supply. Open the WuTech diode array by removing the side panel where the two cable bundles exit. Use a flashlight to inspect if any pre-amp cards are loose (they may appear higher than other cards).
    Warning: NEVER touch the fiber-optics!!
    Push the loose cards back in. If necessary, you can also remove the top plate of the array box. Close the side panel and tighten ALL the screws of that panel. This is important for achieving a light-tight and good shielding contact for the array housing.
5.   Connect the array to the power supply by connecting the two small white three-lead connectors, one from the power supply and one from the array. Make sure that the gain is set on "low" for pre-amplifiers before turning on the power. Turn on the power supply while inspecting the LEDs on the Array housing. The two LEDs, +15V and -15V should be on, indicating the power to the array is correctly connected. Turn on the switch labeled "LED" on the array housing. Remove the cover on the fiber aperture by removing the four screws of the centering disk. Look into the array aperture. There should be five lit fibers at five corners of the hexagon. These lit fibers can be used for orienting the array and aligning the detectors to the image of the preparation. Warning: Do not touch the fiber optics aperture!! This aperture is softer than most of metals and is easily scratched. Turn off the LEDs and turn the gain switch to "low". Then turn off the Power supply for the next step.
6.   Connect the two cable bundles from the array module to the post-amp cards. Place the PostAmp Module facing the array. Lay the cable bundles on top of the PostAmp Module down to the rear of the module. Looking into the rear of the module, you should see the input connectors of the second stage amplifier cards ( 2 connectors for each card, 16 in total). Plug the connectors top-down. When facing the rear of the PostAmp Module, the bundle labeled "left" should be plugged into the left row connectors.
7.   Identify the power cable for the PostAmp Module. This is a short, multicolored and twisted wire cable with a 9-lead white block connector at the end. Connect this cable to the cable-of-the-same-type from the power supply module.
8.   Identify the flat cable labeled # 4. On one end of this cable there are several connectors already connected to the PostAmp Module before shipping. On the other end is a 37 pin female "D" connector. Plug this connector to the 37 pin male "D" connector at the back of the Output-Amp Control Panel.
9.   Replace the rear panel of the PostAmp Module. Use the four nylon spacers in between the rear panel and the rack to leave space for the cables. Make sure the computer is on and the two LED indicators for computer power on the front panel of the PostAmp Module are lit. Turn on the Power Supply Module while inspecting the LEDs on the front panel of the PostAmp Module. The four indicators, +/-15V, and +/- 8V should be all on indicating the power supply to the second stage is correctly connected.
Warning: NEVER turn on the PostAmp power while the computer power is off. This is because the A/D converter can be damaged when the input voltage is higher than its power supply voltages. Always watch the indicators on the front panel of the PostAmp Module. If the computer power is off, turn off the Post Amp power immediately. This panel is designed with this purpose since some modern computers can be shut off with power saving or other software controls.


10.   Now when the PostAmp Module is on, LED indicators on the right half of the Output-Control panel are indicating the settings for the 2nd stage amplifiers. Use a black cloth to cover the array aperture and take data again. This data is the dark noise of the system. The RMS value of the dark noise can be obtained from the software. A measure for this system is follows: When the gain on the PreAmp is high(1Gohm) and Post Amp Gain=1000X, HP=AC2 and low pass filter = 500 Hz, the RMS noise for most of the detectors is around 300 mv. This value converts to an input current of the PreAmp of about 300 pA, close to the theoretical Johnson noise of the feedback resistor at 500 Hz bandwidth. If the dark noise is significantly higher than this value, make sure the array is sealed in the complete dark. Also, use the FFT function of the NeuroPlex to check if there is any 60 Hz noise in the system.
Dark Noise
Measure the dark noise with a filter setting of 1 kHz and using the fastest acquisition rate (1.3 usec). In addition to determining the size of the dark-noise by measuring its RMS value, determine its frequency content by using the FFT option under Trace. There should be little or no line frequency (or harmonics) noise as well as no increase at high frequencies (which would indicate oscillations). A flat spectrum is good.
Measure 60 (or 50) HZ Noise
Turn the gain of the PreAmp to low and the gain of the PostAmp to 1000X, high pass filter to AC2 and low pass filters to 10X, 33 (330 Hz). Cover the system with cloth to isolate the room lights. Take data again and use FFT display with cut-off frequency 10 Hz to 330 Hz. If the system is connected correctly, there should be no peaks at 60 Hz, 120 Hz or 180 Hz in the FFT display (50 Hz, 100Hz or 150 Hz for countries that use 50 Hz).

There is a center ground point at the 2nd stage rack where the 2nd stage ground, array box, and power supply ground are tied together. If there is still line frequency noise present with the light off, you might try connecting the other grounds in the apparatus to this central ground.
Inspect Cable Connection And Dead Detectors
Turn the gain of the PreAmp to low and the gain of the PostAmp to 50X. In a dark room, illuminate the array aperture with a LED blinking at 100 Hz. Take data when different parts of the aperture are illuminated. You will see this blinking signal on the Page Display screen. Check that the Page Display screen agrees with the illumination on the aperture. If not, there may be errors in the connection of the cables between the PreAmp and the PostAmp (the two cable bundles). In this way you can also find dead channels. In the test before shipping, this system has five or fewer dead channels. This is the final step for installation.

Congratulations and enjoy the new system!

Jiang-young Wu, Ph.D.
WuTech Instruments
11810 Charen Lane
Potomac, MD 20854

Chun Falk, Ph.D.
Lawrence Cohen, Ph.D.
RedShirtImaging, LLC
2 Stoneleigh Road
Fairfield, CT 06825

Control Panel Outputs:
0 Shutter (0 & 13)
1 Lamp
2 Stimulus
12 Reset
13 Shutter
14 Start
Test Not implemented
Abort When it is on, the panel does not respond to input signals.
Remote control Not implemented
Reset Manual reset
For External Triggering
4th BNC Input