Two-wire barometric pressure transducer system is relatively simple, the average customer knows how to wire, a line connecting the positive power supply, the other line is the signal line through the instrument connected to the negative power supply, this is the simplest.
Three-wire barometric pressure transducer is in two-wire was added to the wire system. This wire was directly connected to the negative pole of the power supply, which was a little more troublesome than the two-wire system.
The four-wire barometric pressure transducer is definitely two power inputs and the other two are signal outputs. Most of the four-wire system is the voltage output instead of the 4-20mA output. The 4-20mA is called the pressure transmitter. Most of them are made in two-wire system. Some of the pressure sensor's signal outputs are not amplified. The full-scale output is only a few tens of millivolts. Some pressure sensors have internal amplifier circuits and the full-scale output is 0 to 2V. As for how to receive the display meter, it depends on how large the range of the meter is. If there is a gear that is suitable for the output signal, it can be directly measured, or the signal adjustment circuit must be added.
The five-wire barometric pressure transducer is not much different from the four-wire system, and there are fewer five-wire barometric pressure transducer on the market.