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Adjustment & use
13. Adjustment & use
IMPORTANT : First have the circuit "warmed up" for about 10 minutes before starting adjusting!
Connect the transmitter (type KTY11, KTY81-22 or equivalent) with the points SENSOR of the pcb, us-
ing a piece of screened wire (+/- 50cm). The polarity is of no importance.
Connect a DIGITAL measuring apparatus between the two connection wires of R2 and R7.
Connect 12VDC to the points +VS and -VS.
REMARK : Be careful to not touch the circuit with your hands while adjusting it, because this could cause
noise at its output, and consequently a very unstable read out.
Fill a glass with ice cubes and let them melt a little until you get ice-water.
Plunge the transmitter into the melting ice-water (0°C). Take care that the connection wires of the trans-
mitter do not touch the water.
Adjust the OFFSET trimming potentiometer RV1, so that the meter indicates 0V (possibly select a more
sensitive measuring range) and wait until the indication becomes stable.
THIS ADJUSTMENT IS VERY IMPORTANT, SO CARRY IT OUT VERY CAREFULLY!
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