And the output voltage for the circuit fig
| 210 |
|
Resistance Values, Angle, and Vout for Various Liquid Levels with Float Sensor | ||||||
|---|---|---|---|---|---|---|---|---|
| TABLE 12.1 | ||||||||
| Fluid level | E | 1/8 | 1/4 | 1/2 | 3/4 | F | ||
| cos−1θ | 0 | 7/8 | 3/4 | 1/2 | 1/4 | 1 | ||
| Θ degrees | 0 | 28.9 | 41.4 | 60 | 75.5 | 90 | ||
|
0 | 3.2 | 4.6 | 6.66 | 8.3 | 10 | ||
| 10 | 6.8 | 5.4 | 3.33 | 1.7 | 0 | |||
| 0 | 3.2 | 4.6 | 6.7 | 8.3 | 10 | |||
Figure 12.9 Characteristic output voltage (a) plotted against liquid level for an uncompensated and compensated float sensor and (b) the circuit with a compensated potentiometer.
| Signal Conditioning | 211 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| TABLE 12.2 |
|
|||||||||
| Fluid level | E | 1/8 | 1/4 | 1/2 | 3/4 | |||||
| 2.14 | 2.69 | 3.3 | 3.65 | |||||||
|
10 | 6.8 | 5.4 | 3.3 | 1.7 |
|
||||
| 0 | 2.4 | 3.3 | 5 | 7 | ||||||
| 12.5.3 | ||||||||||
Figure 12.11b shows a circuit using the strain gauge. The strain gauge ele-ments are mounted in two arms of the bridge and two resistors, R1 and R2, form the other two arms, R3 and R5 are the conditioning for the zero offset and span, respectively. The output signal from the bridge is amplified and impedance matched, as shown. The strain gauge elements are in opposing arms of the bridge, so that any change in the resistance of the elements due to temperature changes will not affect the balance of the bridge, giving temperature compensation.
