Pressure transmitters are devices that convert pressure measurements into an electrical signal for monitoring and control purposes. They are essential in various industrial applications, and their classification can be based on several criteria:

1. Based on Measurement Principle

• Strain Gauge Transmitters: Utilize a strain gauge that deforms under pressure. The deformation changes the electrical resistance, which is measured and converted into a pressure reading.

• Capacitive Transmitters: Use capacitive sensors that change capacitance with pressure variations. These are often used for precise measurements in low-pressure applications.

• Piezoelectric Transmitters: Employ piezoelectric materials that generate an electrical charge in response to pressure changes. They are suitable for dynamic pressure measurements.

• Resonant Pressure Transmitters: Measure pressure based on the frequency change of a resonating element when pressure is applied.

2. Based on Output Signal

• Analog Pressure Transmitters: Provide a continuous output signal, typically in the form of 4-20 mA or 0-10 V, which is proportional to the measured pressure.

• Digital Pressure Transmitters: Output digital signals, often using protocols such as HART, Modbus, or Fieldbus, allowing for more complex data communication and diagnostics.

3. Based on Construction Type

• Flanged Transmitters: Feature flanges for mounting in pipelines, ideal for high-pressure applications.

• Sanitary Transmitters: Designed for hygienic applications, often used in food and pharmaceutical industries. They are made from materials that meet sanitary standards.

• Intrinsically Safe Transmitters: Designed to operate in hazardous environments without posing a risk of ignition, making them suitable for use in explosive atmospheres.

4. Based on Pressure Type

• Absolute Pressure Transmitters: Measure pressure relative to a perfect vacuum, used in applications where atmospheric pressure fluctuations must be considered.

• Gauge Pressure Transmitters: Measure pressure relative to atmospheric pressure, indicating how much pressure is above or below the atmospheric level.

• Differential Pressure Transmitters: Measure the difference between two pressure points, commonly used in applications such as flow measurement and level detection.

5. Based on Application

• Industrial Pressure Transmitters: Designed for use in various industrial processes, featuring rugged construction for harsh environments.

• Environmental Pressure Transmitters: Used for monitoring atmospheric pressure and environmental conditions.

• Process Pressure Transmitters: Specifically designed for monitoring pressure in chemical, oil and gas, and other process industries.