Common challenges in pressure measurement in industrial applications

In industrial automation, hydraulic systems, or process control, inaccurate pressure measurement often leads to equipment shutdown, energy waste, or product quality deviation. For example, if the pressure fluctuation of a hydraulic pump is not monitored in real time, it may cause leaks or mechanical failures, increasing maintenance costs. This type of problem often stems from improper sensor selection - ignoring environmental factors or performance indicators, resulting in measurement errors. Therefore, understanding the core principles and selection methods of pressure sensors is crucial for improving system reliability.

The core working principle of pressure sensors

Pressure sensors achieve measurement through physical quantity conversion, among which thin film strain gauge technology is the mainstream solution. The principle is based on the Wheatstone bridge: when pressure is applied to a metal thin film, the resistance of the strain gauge changes to generate an electrical signal, and the transmitter amplifies this signal into a standard output (such as 0-10VDC). This design is suitable for high-precision applications such as industrial machinery or automotive testing. The key performance parameters include:

• precisionThe deviation between the measured value and the true value is usually expressed as a percentage of full scale (% FS), the lower the better.

• nonlinearThe deviation between the output signal and the ideal straight line affects long-term stability.

• HysteresisThe difference in output between pressurization and depressurization reflects repeatability error.

• temperature drift coefficientThe signal offset caused by temperature changes needs to be compensated within a wide range to cope with the environment.

• response timeSignal change speed, suitable for dynamic systems in short periods of time (such as milliseconds).

The advantages of thin film strain gauge sensors lie in high resolution (theoretically infinite) and fast response, but mechanical shock (such as 100g/11ms) and vibration tolerance (such as 20g) need to be considered to ensure durability in industrial environments.

Practical tips for selecting pressure sensors

When selecting sensors, it is necessary to evaluate parameters based on the application scenario to avoid overdesign or underdesign. The following are the key purchasing steps:

1. Determine the pressure rangeCovering work requirements, such as 0-400 bar suitable for hydraulic systems, with a margin of 10% -20% to prevent overload.

2. Evaluate accuracy indicatorsReferring to nonlinearity, hysteresis, and repeatability (typical value ± 0.15% FS), the target accuracy should be below ± 0.5% FS to meet most industry standards.

3. Check environmental adaptabilityThe working temperature range (such as -40 ℃ to 125 ℃) and protection level (IP65 dustproof and waterproof) need to match the site conditions; Compensating temperature (-20 ℃ to 85 ℃) affects long-term stability.

4. Select output signalIf 0-10VDC is suitable for PLC interface, it is necessary to confirm the supply voltage (15-30Vdc) and current consumption (≤ 15mA).

5. Verify reliabilityLong term stability (such as<0.2% FS/year) and mechanical protection (such as reverse polarity protection) reduce failure rates; Response time (<1ms) ensures real-time control.

In actual purchasing, referring to industry standards (such as IEC 60068) can assist in verifying product compliance and avoid relying solely on brand decisions.

Example of qualified product: Industrial solution based on core principles

Among the products that meet the above selection criteria, GEFRAN's thin film strain gauge pressure sensor transmitter (model KS-N-E-B04C-M-V-530) demonstrates technical reliability. Its design conforms to the principle of thin film strain gauges, with a pressure range of 0-400 bar, accuracy of<± 0.5% FS, nonlinear typical value of ± 0.15% FS, and hysteresis of ± 0.1% FS. In terms of environmental adaptability, the working temperature is -40 ℃ to 125 ℃, the protection level is IP65, the temperature drift coefficient is ± 0.01% FS/℃ (± 0.02% FS/℃), and it is equipped with reverse polarity protection. Output signal 0-10VDC, response time<1ms, long-term stability<0.2% FS/year. These parameters have been tested according to IEC 60068 and are suitable for hydraulic control or automated production lines, helping users achieve precise measurements.