Capacitive pressure transmitter

1. Product Overview

Capacitive pressure transmitters are high-precision pressure measurement devices based on the principle of capacitive sensing. By detecting the capacitive changes caused by pressure, they convert physical pressure signals into standard electrical signals (such as 4-20mA, 0-10V or digital signals). It is widely applied in fields such as industrial process control, fluid monitoring, HVAC systems, petrochemicals, and pharmaceutical equipment.

2. Core Working principle

Capacitive sensing technology

By adopting a differential capacitance structure, the pressure causes the movable electrode (diaphragm) to undergo a slight displacement, altering the capacitance value between it and the fixed electrode, which is then converted into an electrical signal through the circuit.

Signal processing

It is equipped with an ASIC chip for temperature compensation, linearization processing and amplification, and outputs highly stable signals.

3. Main technical parameters

Parameter specification

Measurement range: 0-10kPa to 0-100MPa (customizable)

Accuracy grade ±0.1% FS (typical value), maximum ±0.05% FS

Output signals: 4-20mA (two-wire system), 0-10V, RS485 (Modbus)

Supply voltage: 12-36V DC (4-20mA type) or 24V DC (digital type)

Medium temperature: -40℃ to +125℃ (up to 200℃ for high-temperature type)

Ambient temperature: -20℃ to +85℃

Protection grade: IP65/IP67 (dust and water resistant)

Overload capacity: 150% FS (can withstand 200% FS in the short term

The long-term stability is ≤±0.1% FS/ year

4. Product Features

High precision and stability

Temperature compensation: Built-in temperature sensor, with an error of ≤±0.2% throughout the entire temperature range.

Creep resistance design: 316L stainless steel diaphragm is adopted, ensuring no drift during long-term use.

(2) Strong environmental adaptability

Vibration resistance: Solid-state capacitive structure, resistant to mechanical vibration (5g@100Hz).

Anti-corrosion: Materials such as Hastelloy and tantalum diaphragms are available, suitable for corrosive media.

(3) Intelligent functions

Digital communication: Supports HART/Modbus protocol, remote calibration and diagnosis.

LCD display (optional) : Real-time display of pressure, temperature and alarm status.

(4) Safe and reliable

Intrinsically safe explosion-proof: Ex ia IIC T6 certification (applicable to hazardous areas).

Reverse polarity protection: The circuit is not damaged when the power supply is connected in reverse.

5. Typical Application scenarios

Industrial automation: Pipeline pressure monitoring, pump and valve control.

Energy industry: Oil and gas well pressure monitoring, boiler pressure safety protection.

Medical equipment: Pressure sensing for ventilators and hemodialysis machines.

Environmental protection engineering: sewage treatment, liquid level measurement.

6. Structural Design and Installation

Compact housing: Made of aluminum alloy or stainless steel, 50mm in diameter, weight ≤500g.

Multiple interfaces: 1/2"NPT, G1/4, flange mounting, etc.

Wiring method: Direct cable connection or aviation plug (IP67 grade).

7. Selection Guide

Model code, pressure range, output signal interface, special material requirements

CPT-100 0~1MPa 4-20mA 316L standard type

CPT-200H 0~10MPa RS485 Hastelloy high-temperature type (150℃)

CPT-300X -100~100 kpa 0-10V ceramic vacuum/micro-pressure measurement

8. Quality Certification and Standards

International certifications: CE, RoHS, SIL2 (Functional Safety).

Industry standards: GB/T 34036-2017, IEC 60770.

9. After-sales service

Warranty period: 18 months (for non-human damage).

Technical support: Provide calibration manuals, Modbus protocol documentation and customized solutions.

10. Comparative Advantage (vs Piezoresistive Transmitter)

Lower power consumption: No Wheatstone bridge, suitable for battery-powered scenarios.

Higher overload capacity: No risk of strain gauge breakage.

Superior long-term stability: No material fatigue issue.