Vacuum Pressure Transducer | Read Before Purchasing

September 2, 2025

Pressure sensors are categorized into absolute pressure sensors, gauge pressure sensors, and differential pressure sensors. Both absolute and gauge pressure sensors can be used to measure vacuum pressure. Vacuum pressure transmitters are manufactured from various materials. such as stainless steel. And they are available for customization. The measurement range of vacuum pressure transmitters spans from absolute zero pressure to local atmospheric pressure (approximately 0-1 bar).

This article provides a detailed introduction to vacuum pressure transmitters.

What is a Vacuum Pressure Transmitter?

Vacuum pressure occurs when absolute pressure is lower than atmospheric pressure. It represents the difference between absolute pressure and atmospheric pressure—a state of negative pressure. A vacuum pressure transmitter is an instrument designed to measure vacuum pressure. It offers selectable analog or digital signal outputs. It can facilitate integration into automated control systems.

Advantages:

High accuracy
Excellent stability
Compact size
Cost-effective
Compact size
Lightweight
Customizable measurement materials
Diverse pressure interface options
Multiple output signal formats
Field-adjustable
Display capability

Vacuum Pressure Transmitter Working Principle

The working principles of vacuum pressure transmitters generally fall into three categories: diffusion silicon vacuum pressure transmitters, single-crystal silicon vacuum pressure transmitters, and capacitive vacuum pressure transmitters. Detailed descriptions as follows:

Capacitive Vacuum Pressure Transmitter

This pressure transmitter operates on the principle of capacitance variation. Changes in applied pressure alter the internal gas pressure within the sensor. This pressure shift modifies the distance between the plates of a pressure-sensitive capacitor. Consequently, this change in plate spacing causes the capacitance value to vary. Therefore, measuring the capacitance change enables the determination of vacuum pressure.

Diffused silicon vacuum pressure transmitter

It consists of a sensor and signal processing circuitry. The sensor pressure face incorporates a Wheatstone bridge. When pressure increases, the resistance values of each bridge arm change. Signal output processing circuitry converts these resistance values into voltage. It ultimately generates a standard signal output. Diffused silicon vacuum pressure transmitters are the most common type.

Single-crystal silicon vacuum pressure transmitter

It operates based on the piezoresistive effect of single-crystal silicon. When pressure is applied to the silicon, the crystal lattice structure undergoes deformation. Then, this deformation causes a change in the crystal’s resistivity, which is directly proportional to the applied pressure. By incorporating a Wheatstone bridge circuit onto the silicon, the resistive value is converted into an electrical signal. After amplification and processing, a standard electrical signal proportional to the pressure is ultimately output.

Sino-Inst Featured Vacuum Pressure Transmitters

Vacuum Pressure Transmitter Applications

Based on Sino-Inst’s extensive experience, vacuum pressure transmitters are commonly used in the following scenarios:

In physics, chemistry, and materials science experiments, precise pressure control is crucial for obtaining accurate results.
In spacecraft design and testing, vacuum pressure can simulate space environments, improving spacecraft safety and stability.
In semiconductor manufacturing and chemical production, vacuum pressure monitoring controls the production environment.
In food processing, vacuum pressure transmitters play a vital role in ensuring safe packaging under vacuum conditions. Monitoring vacuum pressure can extend shelf life and maintain quality.

In short, vacuum pressure measurement is crucial to improving production levels and efficiency.

Vacuum Pressure Transmitter Signal Output

Vacuum pressure transmitters primarily output the following signal types:

1. Analog Signal

The 4-20mA is one of the most common analog signals in industrial applications. This signal ranges from 4 to 20 mA. 4 mA represents 0% pressure and 20 mA represents 100% pressure. Advantages of the 4-20mA signal include strong interference resistance, long transmission distances, and easy interfacing with PLCs and other industrial control systems.

Voltage signals are another analog signal. Their output voltage range can be selected as 0-5V or 0-10V. This signal type is preferred over 4-20mA in certain applications because it can connect directly to some types of secondary instruments without requiring an additional converter.

2. Digital Signals

HART is a digital communication protocol enabling both analog signals. And digital signals to transmit over the same pair of wires. The HART protocol supports device configuration, diagnostics, and monitoring. It makes pressure transmitters more intelligent.

3. Modbus and RS-485 are fieldbus-based digital communication protocols. It connects devices within distributed control systems. It supports high-speed data transmission. Make it suitable for applications requiring extensive data exchange.

When outputting signals, we need to consider the following aspects to ensure the possibility of problems in subsequent use.

For long-distance transmission, select a type with minimal signal attenuation. 4-20mA is typically used for short-range transmission (within 200m). RS-485 can be used for longer distances (around 1000m).
In environments with severe electromagnetic interference, choose a signal type with strong interference resistance.
Ensure that the output signal is compatible with the existing control system or display device. If it is not, the correct signal will not be output.
Wireless signals can reduce wiring work, but may require additional maintenance, which increases workload.
We need to consider system costs and select a cost-effective signal type to save costs.

How to Calibrate a Vacuum Pressure Transmitter？

A vacuum pressure transmitter is an instrument that measures pressure and converts it into an electrical signal. We recommend the following common pressure transmitter calibration methods.

Automatic Calibration Method

Automatic calibration is suitable for large equipment or transmitters that are difficult to disassemble. This method requires specialized automatic calibration equipment. By connecting the transmitter to be calibrated to a standard measuring instrument, the system automatically adjusts the output to match the standard value.

Manual Calibration Method

The transmitter is connected to a known standard pressure gauge under specified process conditions. Using the readings from a comparator, the transmitter output is adjusted to match the standard value. It is suitable for smaller equipment.

Online Calibration Method

Online calibration is suitable for equipment that cannot be shut down for calibration. This method compares the output of the pressure transmitter during normal operation with a regularly calibrated standard measuring instrument, enabling online calibration.

Precautions for Using Vacuum Pressure Transmitters

Prevent contact between the transmitter and corrosive or excessively hot media;
Prevent debris accumulation inside the conduit.
When measuring liquid pressure, position the pressure tapping port on the side of the process pipe to avoid sediment buildup.
When measuring gas pressure, position the pressure tapping port at the top of the process pipe. Additionally, install the transmitter in the upper section of the process pipe. To facilitate drainage of accumulated liquid back into the process line;
Install pressure-conducting pipes in areas with minimal temperature fluctuations;
When measuring steam or other high-temperature media, connect a condenser (such as a coil pipe). To prevent the transmitter’s operating temperature from exceeding its limits;
During winter freezing conditions, outdoor transmitters must implement freeze protection measures. This prevents sensor damage caused by volume expansion of frozen liquid within the pressure ports;
When measuring liquid pressure, avoid installing the transmitter where it may be subjected to liquid impact (water hammer phenomenon). To prevent sensor damage from overpressure;
During wiring, route cables through a waterproof connector (accessory) or flexible conduit and tighten the sealing nut. To prevent rainwater or other liquids from leaking into the transmitter housing through the cable.

What is the maximum pressure for a pressure transmitter?

Sino-Inst’s pressure transmitter can be customized for a maximum pressure of up to 1000 MPa.

What is the Difference between a Pressure Switch and a Pressure Transmitter?

Pressure switch and pressure transmitter have some differences. There are some differences features based on our experiences:

Pressure Switch Features:

Pressure switches operate according to a set value. When pressure reaches or exceeds the set value, the switch opens or closes. They are designed to activate or deactivate a circuit based on increases or decreases in system pressure.
Pressure switches have a relatively simple structure. They typically detect pressure mechanically or electronically.
They are widely used in various applications requiring automatic control based on pressure changes. They are primarily used in air conditioning systems, hydraulic systems, and safety protection systems.

Pressure Transmitter Features:

They convert pressure into analog or electronic signals for measurement, recording, or system integration control.
It is commonly used in applications requiring precise pressure measurement. such as industrial automation, environmental monitoring, and medical equipment.
Primarily, they transform pressure applied to an object into an electrical signal for connection to a control system. These transmitters provide continuous output and are typically connected to controllers that monitor and respond to pressure.

Why is vacuum pressure important?

The importance of measuring vacuum pressure is reflected in the following aspects:

Product Quality: In sectors like food packaging and pharmaceutical manufacturing, vacuum environments extend product shelf life. Vacuum pressure monitoring ensures packaging achieves the required vacuum level. Thereby guaranteeing product integrity.

Safety Protection: In certain scenarios, such as high-pressure vessels or reactors, vacuum pressure monitoring can prevent equipment damage or explosion, thereby ensuring the safety of personnel and assets.

Equipment Operation: Many industrial processes, such as vacuum coating and vacuum drying, require precise pressure control to achieve desired outcomes. Monitoring vacuum pressure ensures these processes operate under correct pressure conditions.

In summary, vacuum pressure transmitters are important for monitoring vacuum pressure. Selecting a right vacuum pressure transmitter for your specific operating conditions is very important.

Sino-Inst is a China-based supplier of vacuum pressure transmitters. Our products support customization and OEM solutions. Feel free to contact us anytime—we can provide complimentary recommendations for suitable vacuum pressure transmitters.