Uncovering the Advantages and Working Principle of Two-Wire Pressure Transmitters

The XDB310 pressure transmitter is a two-wire 4-20mA pressure transmitter that is commonly used in industrial control systems. Compared with three-wire and four-wire transmitters, the two-wire transmitter has several advantages, including lower installation and cable costs, longer transmission distances, and better immunity to interference.

The working principle of a two-wire pressure transmitter is based on the concept of a transmitter that converts the output signal from a sensor into a signal that can be recognized by a controller. The transmitter can be used to measure various non-electrical physical quantities, such as temperature, pressure, speed, and angle, in industrial applications.

The structure of a two-wire pressure transmitter consists of three main parts: a sensor, a conditioning circuit, and a two-wire V/I converter. The sensor is responsible for sensing the pressure and converting it into an electrical signal. The conditioning circuit is responsible for amplifying, filtering, and linearizing the signal. The two-wire V/I converter is responsible for converting the electrical signal into a 4-20mA current signal that can be transmitted over a two-wire loop.

The working principle of a two-wire pressure transmitter is based on the 4-20mA signal providing the necessary power to the transmitter. If the power consumption of the transmitter is greater than 4mA, it will not be able to output the lower limit of 4mA. The transmitter's stability and safety in industrial environments are critical, and designer’s need to consider protection and stability enhancement measures.

One of the advantages of the two-wire pressure transmitter is its immunity to interference. It is less affected by parasitic thermocouples, along with resistance voltage drop and temperature drift, which allows the use of cheaper, thinner cables, saving costs on installation and cables. Furthermore, the interference caused by magnetic fields can be reduced by using twisted pair cables.

Another advantage of the two-wire pressure transmitter is its longer transmission distance. Capacitive interference can cause errors in the receiver resistor. Still, for a 4-20mA two-wire loop, the receiver resistor is typically 250Ω, which is small enough to prevent significant errors, allowing for longer and more distant wire lengths than voltage telemetry systems.

The two-wire pressure transmitter has excellent flexibility, allowing different single-reading or recording devices to switch between channels of different wire lengths without causing a difference in accuracy, enabling decentralized collection and centralized control.

The XDB310 pressure transmitter is a high-quality two-wire pressure transmitter that is widely used in industrial control systems due to its stability, reliability, and safety. Its design takes into account the harsh working environment and the requirement for high reliability, making it an excellent choice for industrial applications.