The three wires of a 3-wire pressure sensor are generally red, black and yellow, respectively, power positive, power negative, signal line. Power positive connects to the positive terminal of the DC power supply, power negative connects to the negative terminal of the DC power supply, and the signal line connects to the signal input port of the device.
Three-wire and two-wire system difference:
1, wiring is not the same
Two-wire eye sensor, a line connected to the power supply positive, the other line that is, the signal line through the instrument is connected to the power supply negative, the power supply negative and the signal *** with a line. Three-wire pressure sensor signal line and power negative is separate.
2, the signal output is different
Two-wire pressure sensor signal is current output (4 ~ 20mA), three-wire pressure sensor signal output is voltage output (0 ~ 2V).
Expanded Information:
Pressure Sensor Working Principle
1, Piezo-Resistive Pressure Sensors
Resistive strain gauges are one of the main components of piezo-resistive strain One of the main components of the sensor. The working principle of the metal resistance strain gage is adsorbed on the substrate material strain resistance with the mechanical deformation of the phenomenon of resistance change, commonly known as the resistance strain effect.
2, ceramic pressure sensor
Ceramic pressure sensor based on the piezoresistive effect, the pressure directly on the front surface of the ceramic diaphragm, so that the diaphragm produces a small deformation, thick film resistor printed on the back of the ceramic diaphragm, connected to a Wheatstone bridge, due to the piezoresistive effect of the piezoresistor, so that the bridge produces a pressure proportional to the high degree of linearity, and the excitation voltage proportional to the voltage signal. The standard signal is calibrated to 2.0/3.0/3.3mV/V, etc. depending on the pressure range, and is compatible with strain gauge sensors.
3, diffusion silicon pressure sensor:
Diffusion silicon pressure sensor working principle is also based on the piezoresistive effect, the use of the piezoresistive effect principle, the pressure of the measured medium directly on the sensor diaphragm (stainless steel or ceramics), so that the diaphragm produces a proportional to the pressure of the medium of the micro-displacement of the sensor's resistance to change the value of the sensor, the use of electronic circuits to detect this change, and convert the output of a signal corresponding to this pressure. Output a standard measurement signal corresponding to this pressure.
4, sapphire pressure sensor:
The use of strain-resistive principle of operation, the use of silicon-sapphire as a semiconductor sensitive element, with unparalleled measurement characteristics. Therefore, the use of silicon-sapphire manufacturing semiconductor sensitive components, insensitive to temperature changes, even at high temperatures, but also has very good working characteristics; sapphire radiation resistance is extremely strong; in addition, silicon-sapphire semiconductor sensitive components, no p-n drift.
5, piezoelectric pressure sensor:
Piezoelectric effect is the main working principle of piezoelectric sensors, piezoelectric sensors can not be used for static measurements, because after the external force after the charge, only in the loop has an infinite input impedance is saved. This is not the case in practice, so this determines that piezoelectric sensors can only measure dynamic stress.
Baidu Encyclopedia - Pressure Sensors