According to MEMS Consulting, the value of a measuring instrument is determined by its accuracy. Pressure sensors are also a type of measuring "instrument," widely used in the automotive, healthcare, and industrial sectors. In these applications, ensuring the accuracy of pressure sensors is crucial for ensuring quality control and protecting patient safety.
Piezoresistive pressure sensors , with their advantages of fast response, robustness, wide measuring range, minimal impact of temperature changes on pressure output, and high accuracy, have become a popular choice for measuring instruments. However, if the sensor exhibits uniformity issues or temperature-related errors, calibration or compensation is necessary.
There are two compensation methods for pressure sensors: active compensation and passive compensation. Passive compensation is achieved by correcting the resistor during the manufacturing process and is suitable for pressure sensors operating in environments with small temperature variations. For environments with large temperature variations, active compensation is performed using onboard circuitry or a microcontroller.
At this point, the temperature of the environment surrounding the pressure sensor also needs to be measured periodically using a temperature sensor. This temperature sensor is then installed on the onboard circuitry to correct for temperature-related errors (also known as offset errors). This ensures that the temperature error of the pressure sensor is close to zero, resulting in a wider operating range and better quality.
How should the calibration method for a pressure sensor be selected?
There are two methods for calibrating pressure sensors: (1) the customer calibrates the pressure sensors used in the production line; (2) the pressure sensor manufacturer provides full compensation and delivers the pre-calibrated sensors to the customer for subsequent integration.
There are many reasons why customers want to perform calibration themselves. One reason is that the customer has already installed a microcontroller in the final product, in which case active calibration can be performed by the microcontroller.
The sensor packaging or assembly process used by customers may apply significant stress to the pressure sensor. When this occurs, a calibrated pressure sensor will produce an additional pressure reading due to the stress from the packaging process. This increased pressure will create a new zero point.
The disadvantage of customers performing calibration themselves is that online calibration is difficult to execute and can be highly destructive. Purchasing pre-calibrated sensors is generally less expensive than the specialized equipment and experience required for online calibration. The most critical drawback is the significant time commitment involved in customer-led calibration. Since each sensor requires individual calibration, batch calibration is impossible. Furthermore, the required temperature range for calibration means the equipment needs a considerable amount of time to reach its temperature limits.
Purchasing fully compensated pressure sensors from manufacturers like MeritSensor is more expensive than purchasing uncompensated ones. However, it's important to weigh the various factors; time is money. If too much time is spent on calibration, buying a fully compensated pressure sensor or a calibration component that can be easily plugged in is a good alternative!
This is ideal for companies seeking high output, especially those lacking the equipment, expertise, and processes to ensure online calibration. Typically, pressure sensor manufacturers have the personnel, tools, and expertise to perform calibration.
MeritSensor provides customized solutions
The LP series is a range of pressure sensors from MeritSensor designed for ultra-low pressure applications, covering a wide range of measurement ranges. This type of sensor is well-suited for applications such as continuous positive airway pressure (CPAP) machines because it is compatible with non-corrosive gases. The LP series offers a pre-calibrated option, meaning the pressure sensors are ready for immediate medical use. They are also suitable for industrial applications, as well as air filtration systems and spirometry in healthcare applications.
MeritSensor's PMD series is suitable for low to medium pressure applications. The PMD series is suitable for air and other non-corrosive liquids. This series can also measure differential pressure, absolute pressure, and vacuum. The PMD series is the ideal pressure sensor choice for ink level in printers, operating within a pressure range of 0.34 to 3.5 atmospheres. Calibration is fast and direct in this application due to the use of an external microprocessor. The uncompensated PMD series is also a very popular product.
The TVC series is suitable for harsh dielectric environments such as high-temperature fuels. Its high dielectric resistivity makes it an ideal choice for the automotive industry. The devices feature radial sealing, facilitating module-level integration with minimal stress introduction.
Fully compensated sensors are popular in automotive applications because they integrate time-consuming and out-of-temperature-range calibration into the production process, freeing automotive customers from these problems.
Over the past 25 years, MeritSensor has accumulated extensive experience in the field of piezoresistive pressure sensors. Customers requiring pressure sensors should consider MeritSensor products. MeritSensor offers standard and customized solutions for a wide range of applications. MeritSensor also provides uncompensated, passively compensated components for applications with small temperature range variations, as well as fully compensated components for applications with large temperature range variations.
If customers are unsure which solution is most suitable, MeritSensor can offer assistance. MeritSensor provides customers with time, personnel, and training support to find flexible and innovative solutions that help them successfully bring their products to market.
