Intelligent differential pressure transmitters can be divided into two-wire, three wire, and four wire systems according to their wiring methods. Two power cables and two signal cables. The power supply is connected to 24V DC power. A simple detection method is to use an ammeter or voltmeter and connect it to both ends of the signal line. After the power is connected, the ammeter will have a current of 4ma or the voltmeter will have a voltage of 0V or 1V.

Nowadays, transmitters generally have four wiring terminals, two of which are wired and the other two do not need to be wired. The DC24V power line of the transmitter is also a 4-20mA signal feedback line, which means that your secondary meter or DAS (data acquisition system) AI point needs to have DC24V output.

　　Intelligent differential pressure transmitterThe general output signals are current 4-20mA, 0-20mA, or voltage 0-5V, 1-5V, 0-10, etc. The current type is usually a two-wire or four wire system, and the voltage is a three wire system output. At present, many frequency converters in the city do not have a 24VDC power supply, most of which are 10V. Some transmitters with high power consumption cannot be driven by a 10VDC power supply, so they can only be powered by an external 24VDC power supply. In this way, the frequency converter has four wiring terminals: power supply+, power supply -, feedback+, and feedback -. Current type four wire wiring method: power supply+==power supply+; Power Supply -==Power Supply -; Signal+==Feedback+, Signal -==Feedback -. Current type two-wire system connection ratio: power supply+=power supply+; Signal+==feedback+, power supply -==feedback -. Voltage type three wire wiring method: power supply+==power supply+; Power Supply - (Signal -)==Power Supply -; Signal+==Feedback+, Power - (Signal -)==Feedback -.

　　Intelligent differential pressure transmitterIt can be directly connected to the frequency converter. The power supply can be the 24V power supply on the frequency converter, and the pressure transmitter can be connected in series to the signal circuit.

Check whether the pressure transmitter is of current type or voltage type, and see the output voltage clearly; The voltage output terminal is connected to the external adjustable voltage input terminal of the frequency converter, and is connected to the external adjustable ground of the frequency converter.