Pressure controller

What conversion and processing processes are involved between the original signal output by the sensor and the signal that the pressure controller can recognize?

Signal perception and preliminary conversion
The primary task of the pressure sensor is to accurately sense the pressure changes in the system. Whether it is a mechanical (such as diaphragm, spring tube) or electronic (such as piezoresistance, piezoelectric, capacitance) sensor, its core is to use physical effects to convert the non-electrical quantity of pressure into a measurable electrical quantity or mechanical displacement. For electronic sensors, this process usually involves direct changes in the physical properties of the material, such as the resistance value increases or decreases with the increase of pressure, and the capacitance value changes with the change of the film spacing. Mechanical sensors transmit pressure information through deformation and convert it into a measurable displacement or force.

Signal amplification and filtering
Since the original signal output by the sensor is often weak and contains noise and interference, signal amplification and filtering must be performed. The role of the signal amplifier is to enhance the weak original signal to a large enough amplitude so that the subsequent circuit can accurately identify and process it. Filtering is used to remove high-frequency noise and interference components in the signal and improve the signal-to-noise ratio and stability of the signal. This process is usually implemented using analog circuits, such as low-pass filters, band-pass filters, etc., to ensure the purity and accuracy of the signal.

Signal conditioning and linearization
Although the signal after amplification and filtering is relatively clear and stable, it may still need further conditioning and linearization. Signal conditioning includes adjusting the signal's offset, gain, phase and other parameters to ensure a strict correspondence between the signal and the pressure change. Linearization is the correction of the output characteristics of some nonlinear sensors, and through mathematical algorithms or circuit design, a good linear relationship between the output signal and the pressure change is presented. This process is crucial to improving the measurement accuracy and control performance of the system.

Digital conversion
With the development of digital technology, more and more pressure controller use digital signal processing technology. Therefore, analog signals need to be digitally converted by analog-to-digital converters (ADCs). ADC converts continuous analog signals into discrete digital signals, a process that involves three steps: sampling, quantization and encoding. Sampling is the discretization of continuous analog signals in time; quantization is the mapping of sampled values ​​to a finite number of discrete values; encoding is the conversion of quantized values ​​into binary numbers or other forms of digital codes. The digitally converted signal has higher anti-interference ability and is easier to process by computer.

Signal processing and decision-making
In the digital domain, the pressure controller further processes and analyzes the received digital signal. This process may include advanced processing technologies such as signal denoising, feature extraction, and pattern recognition. Based on the processing results, the controller will make corresponding control decisions, such as adjusting the valve opening, starting or stopping the pump, etc. The decision-making process may involve complex control algorithms and logical judgments to ensure that the system can maintain a stable operating state under various working conditions.

Feedback and closed-loop control
In order to achieve precise pressure control, the pressure controller usually adopts a closed-loop control strategy. This means that the controller will not only make control decisions based on the current pressure signal, but also continuously monitor the pressure changes in the system and adjust the control output based on the feedback signal. Through continuous feedback and adjustment process, the system can gradually approach and stabilize within the preset pressure range. This closed-loop control mechanism ensures the stability and reliability of the pressure control system.