Advantages, disadvantages and choices of inductive sensors
Published time: 2019-12-20 10:53:25
Inductive sensor advantages
(1) The structure is simple and reliable;
(2) high sensitivity, the highest resolution is 0.1μm;
(3) The measurement accuracy is high, and the output linearity can reach ±0.1%;
(4) The output power is large, and in some cases, it can be directly connected to the secondary instrument without amplification.
Inductive sensor disadvantage
(1) The frequency response of the sensor itself is not high and is not suitable for fast dynamic measurement;
(2) The stability of the frequency and amplitude of the excitation power supply is relatively high;
(3) The resolution of the sensor is related to the measurement range, the measurement range is large, the resolution is low, and vice versa.
Inductive sensor selection
(1) Scheme selection
Before selecting a solution, you should first clear the given technical indicators, such as the range of indications, indication error, resolution, repeatability error, time drift, temperature drift, use environment, etc.
(2) Choice of core material
The main basis for the selection of core materials is to have a high magnetic permeability, a high saturation magnetic induction and a small hysteresis loss, and the remanence and coercive force are small. In addition, it also requires a large resistivity, a high Curie point temperature, stable magnetic properties, and easy processing. Commonly used magnetic conductive materials are ferrite, iron-nickel alloy, silicon steel sheet and pure iron.
(3) Selection of power frequency
Increasing the power frequency has the following advantages: it can improve the quality factor of the coil; the sensitivity is improved; the proper frequency increase is also beneficial to the design of the amplifier. However, too high power frequency will bring disadvantages, such as increased eddy current loss of the core; the skin effect of the wire will reduce the sensitivity; increase the parasitic capacitance (including the inter-turn capacitance of the coil) and the influence of external interference.
Inductive sensor product requirements
1. Detect the attenuation of the distance
The sliding is iron, suitable for inductive sensor detection; the size of the tested part is slightly smaller than the standard inspection size (the standard measured object size is 3 times the rated detection distance. In this application, the standard size should be 120*120mm ), in this case there will be a certain attenuation.
2. Anti-interference ability on site
This is a problem that cannot be ignored. Ordinary inductive sensors are easily interfered by motors or inverters. Many technicians only select sensors that are highly resistant to electromagnetic interference for applications in the vicinity. However, in the automobile manufacturing workshop, the factory building is large, and the on-site technicians are accustomed to using the walkie-talkie to communicate, especially when talking with the walkie-talkie while walking, they will inadvertently approach the sensor, resulting in a short-term failure.
3. Installation aspects
With the popularity of inductive sensors, sensors are not only improved in electrical performance, but their mechanical design is becoming more and more user-friendly. To achieve the most humanized installation. Reduces the stocking of multiple approximate products and reduces the time for installation and maintenance.
4. Guarantee of stable operation
In the use of the depot, it is necessary to prevent any oil and dust from eroding. In addition, when the slider passes through the track, the vibration is long-term, and the excellent vibration resistance also plays a very important role.Tag: sensors