Difference Between Pressure Sensor and Pressure Transmitter

In industrial automation, environmental monitoring, and many other fields, pressure transmitters and pressure sensors are two commonly used pressure measurement devices. Although their functions may appear similar, there are significant differences in their working principles, applications, and output signals. This article explains the differences between pressure transmitters and pressure sensors to help users choose the right device for their specific needs.

Working Principle

1. Pressure Sensor

The working principle of a pressure sensor is based on the conversion of physical quantities. When the measured pressure acts on the sensing element, the element deforms, causing changes in a related physical parameter of the transducer component (such as resistance, capacitance, or inductance).

These changes are then converted into an electrical signal through signal processing circuits, thereby achieving pressure measurement.

2. Pressure Transmitter

A pressure transmitter is built on a pressure sensor but integrates a signal conditioning module. Through amplification, filtering, and linearization, it converts non-standard signals into standard output signals such as 4–20 mA current or voltage signals.

An internal closed-loop feedback mechanism ensures a strictly linear relationship between output signal and pressure value. For example, a capacitive transmitter measures capacitance changes caused by diaphragm displacement. After oscillation and demodulation, it outputs a stable signal. Even under long-distance transmission or strong electromagnetic interference, it can maintain high accuracy.

Structural Composition

(1) Pressure Sensor

The core component of a pressure sensor is the sensing element, which detects pressure changes based on physical principles (such as resistance change or capacitance change) and generates a weak electrical signal.

Pressure sensors generally have a relatively simple structure and are suitable for initial signal acquisition in pressure measurement. However, without further signal conditioning, these signals are not suitable for long-distance transmission or direct system integration.

(2) Pressure Transmitter: The pressure transmitter comprises components such as sensing elements, signal conditioning circuits, output interfaces, as well as housing and connection ports. The sensing elements are used to detect and measure pressure; the signal conditioning circuits amplify, linearize, and filter the weak signals output by the sensors; the output interface converts the conditioned signals into standardized industrial signals; while the housing and connection ports protect the internal components and connect with the medium being measured.

Accuracy and Stability

Accuracy

Pressure transmitters generally provide higher accuracy than pressure sensors. With built-in signal conditioning modules, pressure transmitters can process detected pressure signals more precisely, achieving measurement accuracy of ±0.1% FS or better.

In contrast, standard pressure sensors may offer accuracy around ±1% FS or lower, making them suitable for applications where ultra-high accuracy is not required.

Stability

Although both devices offer good stability, pressure transmitters are better able to maintain high measurement accuracy over long-term operation. This is due to their internal signal conditioning mechanisms, which effectively minimize the influence of external environmental factors on measurement results.

Application Scenarios

Pressure Sensor:

Due to their relatively low cost and ease of installation, pressure sensors are widely used in applications requiring real-time pressure monitoring. For example, in industrial automation, pressure sensors can monitor the operating status of machinery to ensure production safety. In medical devices, they can track pressure changes within the human body, providing valuable data for diagnostics. Pressure sensors are also commonly used in industries such as hydropower, rail transportation, and smart buildings.

Pressure Transmitter:

Pressure transmitters are better suited for applications that require precise pressure measurement along with remote transmission and control. In fields such as process control and energy management, including oil & gas, chemical, and water treatment industries, pressure transmitters can accurately convert pressure signals into standard output signals for transmission to a central control room for indication, recording, or automated control. Their high sensitivity and stability ensure accurate measurement and control even in complex environments.

Pressure sensors and pressure transmitters differ significantly in working principle, accuracy, stability, application scenarios, and cost. When selecting a pressure measurement device, the choice should be based on the specific application requirements.

Understanding the differences between these two types of devices allows users to better meet various pressure measurement needs, improving production efficiency and operational safety.

FAQs

Q: Are pressure transmitters suitable for all industrial applications?

A: Transmitters are suitable for scenarios requiring remote signal transmission or interference resistance. However, in extreme temperatures (e.g., ultra-high heat) or highly corrosive media, specialized models or additional protective measures are required.

Q: How can I determine whether a device is a sensor or a transmitter?

A: Check the output signal type: non-standard signals (such as millivolts or volts) indicate a sensor, while standard current/voltage signals (4–20 mA, 0–5 V, etc.) indicate a transmitter.

Q: What is the difference in maintenance cycles between pressure sensors and transmitters?

A: Sensors, due to their simpler structure, generally have longer maintenance intervals. Transmitters, which integrate electronic components, require periodic inspection of power supply, signal lines, and sealing, resulting in a slightly higher maintenance frequency.