Waterproof PT100 Platinum Resister Temperature Sensor Probe Arduino projects robots NEW
External Shielding: Insulated Shielding
Internal Insulation: Fiberglass
Temperature rang: -20℃ ~ 450℃
Cable Length: 49cm
Sensor Length: 3cm
Sensor Diameter: 4mm
R2, R3 and R4 and Pt100 sensor measuring bridge, in order to guarantee the stability of the bridge output voltage signal input voltage of bridge by TL431 to 2.5 V. Differential signal was obtained from the bridge after two stage operational amplifier input microcontroller. A bridge bridge arm with adjustable resistor R3, by adjusting the R3 can adjust the difference voltage signal input to the op-amp, is often used to adjust the zero point. Amplifying circuit adopts the integrated operational amplifier LM358, in order to prevent the single-stage the nonlinear error of too much magnification, amplifying circuit using two stage amplifier, as shown in figure 5.1, former level is about 10 times, after the level is about 3 times. Changes in 0 ~ 100 degrees temperature, when the temperature rises, Pt100 resistance, input amplifier circuit of differential signals, amplifying circuit of Av output voltage corresponding to rise. Note: although the bridge section have been TL431 regulated, but the whole module voltage VCC must be stable, or as the VCC fluctuations, operational amplifier LM358 working voltage fluctuation, Av output voltage fluctuations, then finally lead to the result of the A/D conversion, the measured results jump up and down.