Four errors that the pressure sensor cannot avoid

Pressure sensors are one of the most commonly used sensors in industrial practice. Generally, the output of the ordinary pressure sensor is an analog signal, and the analog signal means that the information parameter appears as a continuous signal within a given range. Or in a continuous time interval, the feature quantity representing the information can be presented as an arbitrary value signal at any instant. The pressure sensors we usually use are mainly made by the piezoelectric effect. Such sensors are also called piezoelectric sensors.

Pressure sensors are the most widely used type of sensor. The conventional pressure sensor is mainly a mechanical structure type device, and the deformation is indicated by the deformation of the elastic element, but the structure is large in size and heavy in weight, and cannot provide an electrical output. With the development of semiconductor technology, semiconductor pressure sensors have emerged. It is characterized by small size, light weight, high accuracy and good temperature characteristics. In particular, with the development of MEMS technology, semiconductor sensors are moving toward miniaturization, and their power consumption is small and reliability is high.

When we choose a pressure sensor, we have to consider his comprehensive precision, and what is the accuracy of the pressure sensor? Or what causes the sensor error? In fact, there are many factors that cause sensor errors. Below we pay attention to four unavoidable errors, which is the initial error of the sensor.

First offset error: Since the vertical displacement of the pressure sensor remains constant over the entire pressure range, changes in converter diffusion and laser adjustment correction will produce offset errors.

Second is the sensitivity error: the magnitude of the error is proportional to the pressure. If the sensitivity of the device is higher than the typical value, the sensitivity error will be an increasing function of the pressure. If the sensitivity is lower than the typical value, the sensitivity error will be a decreasing function of the pressure. This error is caused by a change in the diffusion process.

The third is linearity error: this is a factor that has less influence on the initial error of the pressure sensor. The error is caused by the physical nonlinearity of the silicon wafer, but for the sensor with the amplifier, the nonlinearity of the amplifier should also be included. The linear error curve can be a concave curve or a convex curve load cell.

Finally, the hysteresis error: in most cases, the hysteresis error of the pressure sensor is completely negligible because the silicon wafer has a high mechanical stiffness. It is generally only necessary to consider the hysteresis error in situations where the pressure varies greatly.

These four errors of the pressure sensor are unavoidable. We can only choose high-precision production equipment, use high-tech to reduce these errors, and perform a little error calibration at the factory to minimize the error. Meet the needs of customers.