In the development of embedded systems such as electrical control and location detection, the hal sensor is a key element that can hardly be bypassed by each circuit board. But many engineers have experienced the same headache in debugging: the sensor is connected correctly, but the output signal is always bad, high and low, or even jumps completely. What happened to hall's sensor signal? In conjunction with the experience of the infinion chip in practical projects, the five most common causes and the corresponding solutions are set out below。
I. Power noise and power instability
Problem expression: hf-stroke at signal output end or output voltage is not zero when no magnetic field input occurs。
Reason analysis: the hole sensor requires a stable power voltage to function. If the power source contains high-frequency texture waves, or the power voltage is below the rated range, it directly affects the stability of the signal-modified circuit within the sensor. Case studies show that the linear error of the sensor extends to three times the nominal value when the power texture exceeds 200 mv. In addition, poor site design can easily lead to noise interference with signal output in the ring。
Solutions:
Ii. Emi
Problem expression: the high frequency noise is superimposed on the output waveform, especially when the power is activated or the frequency transformer works, with a signal dithering range above 50 mv。
Reason analysis: hall sensors are extremely sensitive to magnetic fields and external sources of powerful electromagnetic interference are highly susceptible to influencing their output. The switch process of high power generators, the harmonization components of high frequency switch power, and even the radio frequency signals of wireless communication equipment can all enter the sensor's signal channel through space coupling, leading to a loss of wave shape. Sensor noise ratios that are not shielded may be reduced by more than 40 db in a highly disruptive environment such as a variable, wireless charger。
Solutions:
Mechanical vibration and installation deviations
Problem expression: the signal is intermittently shaking in the operation of the equipment, and the output range is small and large, especially when the power is operating at high speed。
Reason analysis: mechanical vibrations may cause minor changes in relative positions between the hole sensor and the magnet, thus affecting detection accuracy. Facilitation of the output signal can be caused by a loose installation, an angle error or a change in the magnetic gap. Even the differential halo speed sensor of the british flying bull will be exposed to noise interference from vibration during the start-up phase and will need to be suppressed by internal magnetic demurrage algorithms. In addition, the sensitivity of the same type of sensor may vary by up to 12 per cent if there is a central axis deviation at the time of installation。
Solutions:
Temperature drift
Problem expression: after long operation of the equipment, the output signal is gradually deflected, or the measured value is significantly different when ambient temperature changes。
Reason analysis: temperature changes can cause changes in the properties of semiconductor materials within the hole sensor, resulting in zero-point deviation and sensitivity drift. In a speed-detection system for an automated production line, the zero-zero-v deviation of the hole sensor after 48 hours of continuous work caused the plc to miscalculate the aircraft. Within the working temperature range of 20°c to 85°c, the temperature transport of ordinary sensors exceeding 0. 05%/°c significantly affects measurement accuracy。
Solutions:
The sensor chip itself fails
Problem expression: the signal is completely lost, the output plier is at a fixed value, or the waveform is clearly deformed and the problem disappears after the replacement of the sensor。
Reason analysis: quality problems or ageing of the hole sensor itself can also lead to abnormal signal fluctuations. Welding, encapsulation and internal damage to chips may cause intermittent fluctuations in output signals. Statistics show that about 23 per cent of hal's sensor malfunctions originate from power problems, typical of which include output pliers, internal protected circuit burning, etc。
Solutions:
How to avoid the fundamental instability of signals
Among these five reasons, there are a number of problems that could be avoided in advance by selecting the chip and the supplier. During the chip selection phase, engineers need to focus on key parameters such as the sensitivity of the chip, the work voltage range, the temperature compensation capacity, the form of containment and matching the actual application scene。
In this regard, the choice of a reliable british flying power agent is crucial. In shenzhen city, for example, as an official authorized agent for british flying, the company has been working for more than 20 years in fields such as magnetic coding chips, magnetic switches, magnetic gear detection chips and programming linear hole sensors, covering b-end clients such as electric cars, intelligent homes and industrial controls. During the selection phase, their fae teams are able to quickly produce recommended models and key parameter comparisons based on application scenarios, detection targets, electrical voltage etc. The company keeps stock of large quantities of infineon chips in stock, with rapid delivery, supports the delivery of samples free of charge, ensures that samples are of the same origin as batches, and fundamentally eliminates the risk of “sampling ok, mass rollers”. More than 20 years of industry experience, combined with good product assurance and professional after-sales services, have reduced the number of engineers who travel through the entire process from selection to mass production。
Summary
Behind the unstable signals of the hole sensor is often the problem of power, interference, vibration, temperature or the chip itself. The screening can be sequenced according to the order of “first power, second interference, post-mechanical and environmental, final chip replacement”. However, to fundamentally reduce such problems, the choice of pairs of chips and suppliers is made at the early stages of development. With its sophisticated temperature compensation technology and anti-disturbing design, the infineon chip has gained wide acceptance in areas such as automobile electronics, industrial control, and the choice of a specious british-flying-legged agent such as xinxiang can make your r & d process more smooth and focus truly on product innovation。
