Description Of Temperature Drift Treatment Of Liquid Level Sensor

In the development and application of liquid level sensors, it is often encountered that the output of the required transmitter is different from the output of the existing transmitter, or the output of the user's existing transmitter cannot meet the new requirements. The original output of the transmitter needs to be changed. In order to meet the needs of various customers, a transmitter with multiple outputs is required. For example: as a second-type meter, the standard output is mostly 0-10mA, or 0-10V, while the currently used three-type meter is 4-20mA or 1-5V. How to change between them is what we must solve problem.

1. Treatment of temperature drift

The temperature drift of the sensor can be divided into zero temperature drift and sensitivity temperature drift. Zero temperature drift is the drift caused by temperature changes when the sensor's output is not under pressure. In sensor applications, constant current power is often used. The zero point and its temperature drift compensation method can be used in series and parallel resistors.

It is a circuit that is usually used to compensate the sensitivity and temperature of the liquid level sensor for the sensor of the current supply bridge circuit. Among them, Rt in the network of R is the thermistor whose temperature coefficient is in the same direction as the temperature drift of sensitivity, and Rs, Rp, Rz are resistances with negligible temperature coefficient, which are used to adjust the temperature coefficient of Rt, and are compensated by the above zero point and sensitivity temperature. The output signal of the sensor can be regarded as independent of temperature changes within a certain temperature range.　　

2. Amplification and nonlinear processing

The non-linearity of any force sensor has its magnitude, plus or minus. The signal processing and transmission must be linearized. The liquid level sensor makes the signal and the liquid level linear. The linearization circuit is designed according to the magnitude and the sign of the non-linearity. The linearization can be carried out in different stages of signal processing, some in the analog signal stage, and some in the digital signal stage.