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shielding for current stability?

F

Fritz Oppliger

Jan 1, 1970
0
I am using AD592AN temp sensors. Connected via split up ribbon cable type
wire , +12V on the high side, voltage divider on the low side> 120K/22.1K
/ AGND, resulting 2.something volts fed past clamping diodes into 4051
MUX, to 16bit ADC CS5501 .

I run 8 sensors in parallel, the wires are about 2 feet long.
To calibrate I put all sensors in a bundle and set their output as equal
to a precision mercury thermometer.

Then I move them apart to measure temp in various places. If I put the
mercury alongside any one of them there now appear discrepancies up to
0.6F .

When I re-calibrate as per above they again agree with the mercury.

The environment is inside an incubator box, with (hopefully grounded)
metal mesh cradles and fans stirring the air .

Question: is there a possible influence of the air flow or charge
potential in the cradles upon the device itself or the wire? Would using
shielded wire make sense?
 
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