When selecting a pressure sensor, we will consider its comprehensive accuracy. But what will lead to its inaccuracy? There are many factors will affect, and in this passage, we will mainly talk about four kinds of unavoidable error, which is also called the initial error of the sensor.
1. Offset error
Because the vertical offset of the pressure sensor remains constant in the whole pressure range, the change brought by converter diffusion and laser adjustment correction will result in offset error.
2. Sensitivity error
The error is proportional to the pressure. If the sensitivity of the equipment is higher than the typical value, the sensitivity error will be an increasing function of the pressure. If lower, then a decreasing function. The error is caused by the change of diffusion process.
3. Linear error
This is a factor which has little influence on the initial error. The error is because of the physical nonlinearity of silicon chip. But for the pressure transmitter indicator with amplifier, the nonlinearity of amplifier should also be included. The linear error curve can be concave curve or convex curve.
4. hysteresis error
In most cases, the lag error of the pressure sensor can be ignored because of the high mechanical stiffness of the silicon chip. Generally, only when the pressure changes greatly should the lag error be considered.
The four kinds of error of pressure sensor cannot be avoided. We can only choose precision pressure sensor and use high-tech to reduce these errors. We can also carry out certain error calibration when leaving the factory to reduce the error as much as possible.