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FMCG/Magnetometer Array Troubleshooting: Difference between revisions
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FMCG/Magnetometer Array Troubleshooting (view source)
Revision as of 20:44, 1 September 2016
, 1 September 2016→High 60 Hz noise
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# Make sure that the cases of the two +5 V power supplies (one for the heater fan and the other for the LCD screen) are not touching. I've seen this generate HUGE 60 Hz noise magnetic fields.
# Make sure the Tristan computer (to the left of the desk), Tristan NI chassis (inside of the shielded room), and chassis fan (controlled with the red and black striped power cable plugged into the white surge protector just behind the laptop) are all turned off. If any one of these is still on, again ask Sarah or Bill if it's OK to turn it off.
# Check to see which output resistors you're using on the shell coils. I've found that using 1k output resistors on the Y can often generate an unacceptably high 60 Hz noise level. With the room coils nulling out most of the fields, it shouldn't be necessary to use such large resistors on the X and Y shell coils. The Z may have to be higher due to Z-mode field requirements, but as that's not one of the two detection directions, it shouldn't be as important.
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