Sensor calibration refers to the process of transmitting the standard value expressed by the norm to the indexing of the sensor's operating range, and the indexing is determined.
The calibration method of the sensor is to use the standard value (such as a known standard force, pressure, torque, displacement, etc.) generated by a standardized equipment as a measuring ruler, input it into the sensor to be calibrated, and obtain the output of the sensor; Then, after mathematically confirming the calibration work (calibration curve), comparing and processing the data, the corresponding relationship between input and output (sensor sensitivity) and its accuracy can be calculated.
The specification value of the regulated device is called the approximate truth value, which can be expressed by the apparent value of the calibrated sensor with a higher level of accuracy. For example, when the accuracy of the load cell is o.1%, the accuracy of the standard force value of the calibration equipment is required to be 0.01%, and at this time, the standard force value can be considered as the approximate true value.
During calibration, the measurement scale of the sensor should be divided into ten levels, and each increase should be 10% of the upper limit of the sensor measurement, in the order of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100, and then the reverse stroke test should be carried out in order. In view of the fact that there are always repetitive errors in the sensor, in order to optimally confirm the calibration line, it is common to perform 3 to 5 or more calibrations in the above calibration sequence.
In addition, it can be seen from the above methods that the basic method of calibration is similar to the method prescribed in the inspection procedures described in the previous chapter, but the calibration is not only to confirm the various operating characteristic curves of the sensor, but also has the concept of "comprehensive error". Some sensors are calibrated and their output values are normalized for easy exchange during use. For example, the sensor used in the electronic scale is calibrated to make it consistent with the weighing scale and accuracy, and the sensitivity is the same, and it can be replaced arbitrarily when used. In the case that the accuracy of the sensor is not high, the sensitivity of the sensor can also be obtained by the more accurate data obtained when measuring the fundamental function in the sensor inspection procedure, and calculated by mathematical methods such as least squares method and average slope method.
Sole calibration method
The independent calibration method is to measure the coefficients of a single sensor, and obtain the sensitivity of the force sensor mV/N or mV/(V•N-1), the sensitivity of the pressure sensor mV/(N.cm-2), and the sensitivity of the displacement sensor V/mm.
Because of the different planning of the sensors, the errors in the processing of the parts, and the elements that are not exactly the same in the installation and conditioning conditions, the sensitivity of each sensor is inconsistent after calibration. However, from the user's point of view, it is hoped that the technical parameters such as sensitivity and input impedance of the same type of product should be the same, and the initial zero output should be as small as possible to reduce the amount of adjustment work in use and improve the measurement accuracy. Therefore, in the process of sensor calibration, there is also the problem of adjusting to meet the requirements of consistency (standardization) of technical parameters.
Combinatorial calibration
In order to calibrate the sensitivity of the sensor to meet the normalization (or commutability) requirements, it can be analyzed and compensated for equivalence using the corresponding methods described in the previous section. However, because the output signal of the sensor in the fundamental circuit is generally relatively small, the weak signal cannot meet the uniform signal required by the appearance or system. On the other hand, the equivalent circuit of the operating principle of some sensors is relatively simple (such as various forms of resistance sensors, which have only one resistor as a parameter), so the equivalent conditions and compensation methods are relatively simple. However, for sensors with operating principles such as capacitance, inductance, eddy current, etc., the equivalent circuit is relatively messy, and the number of parameters to be changed is more to reach the calibration and normalization of sensor sensitivity. Individual sensors are subject to structural conditions. For this purpose, it is calibrated in combination with an electronic amplifier or appearance, and most of the equipment that requires compensation conditioning is placed in the electronic amplifier or appearance.
After calibration in combination with an electronic amplifier, a normalized specification signal can be output, e.g., 0 to 10 mA or 4 to 20 mA, and a 0 to 5 V or 0 to 10 V specification signal. This kind of signal has a certain driving ability to drive various detection, control, conditioning and other appearances and equipment. In order to facilitate the use of measurement, some sensors can be calibrated together with the display appearance or recorded appearance, so that the measured variable can be directly read out or recorded, and the sensitivity conversion is not required.
|
More on that
|
The structure of the miniature tensile pressure sensor
Based on the characteristics of fixed force measurement, the sensor principle structure is selected as a resistance strain force sensor with mature technology and low requirements for the measurement circuit, and the elastomer of one of the key components of the sensor is selected S-beam structure, as shown in Figure 1. When subjected to pressure P, the ...
|
|
The FDH-1 simplifies bus installation
1. Mastery: Take control of your bus
The handheld bus diagnostic device FDH-1 can be regarded as an increasingly intelligent multimeter. It only needs to press a button to quickly view any network segment. And it can work independently, which is a good addition to the engineer's stuff box.
...
|
|
Problems and analysis of P+F encoders in use
Analysis of the causes of the problems encountered by P+F in the use of encoders:
1. Grating pollution This will reduce the signal output amplitude, and the oil must be quietly wiped off with absorbent cotton dipped in anhydrous alcohol.
2. Encoder connection cable ...
|
|
The selection of safety barriers
1) The operating voltage of the safety equipment connected to the safety barrier shall not exceed the maximum acceptable voltage of the safety barrier. Otherwise, it should be isolated from the system by using techniques such as optical resistance insulation, or using barrier safety barriers;
...
|
|
Features and functions of photoelectric switches of the sensor
Photoelectric switches are what we generally call sensors. The national standard GB7665-87 defines the definition of the sensor: a device or device that can sense the measured part of the rule and convert it into a usable signal according to the certain rules, which is generally composed of a sensitive element and a conversion element.
...
|
|
Encoder classification form
1. Classification according to the way of engraving the disc is different
(1) Incremental type: that is, every time the viewpoint of the unit is rotated, a pulse signal is announced (there is also a sine and cosine signal, and then it is subdivided, and the pulse with a higher frequency is chopped), which is generally output for phase A, phase B and Z, and phase A and phase B are ...
|
|
Selection criteria for proximity switches
Points to note in the selection of proximity switches
1. The working voltage of the proximity switch output is selected, generally DC type DC24V or AC AC250V optional;
2. Proximity switch output method selection, generally NPN-normally open, NPN-...
|
|
Ultrasonic level gauge installation principle
1. The interval from the launch surface of the probe to the liquid level should be smaller than the range of the purchased surface.
2. The interval between the launch surface of the probe and the highest liquid level should be greater than the blind area of the purchased surface.
3. The launch surface of the probe should be parallel to the surface of the liquid.
...
|
|
The correct way to test the output of the sensor – the sensor
1. Test for NPN output sensor
The NPN sensor output, also known as OC gate output, is based on the principle of open collector output of a transistor.
The principle of NPN type OC gate output is whether the output of the NPN transistor and GND are short-circuited. When the control is active, the transistor is turned on, the output and the GND ...
|
|
Common faults and solutions of linear displacement sensors
1. If the electronic ruler has been used for a long time, and the seal is now aged, and there are many impurities mixed with it, and the water mixture and oil will seriously affect the contact resistance of the brush, which will make the displayed numbers keep jumping. At this time, it can be said that the electronic ...
|
|
Benefits and features of our industrial sensors
The R2 and R3 series of photoelectric sensors are impressive products that characterize a very small housing plan. Robust R2/R3 miniature photoelectric sensors – smaller than a matchbox, space-saving miniature housing photoelectric sensors R2/R3 series ...
|
|
Analysis of the causes of repairs encountered in encoders – Doublebless
1. Encoder self-failure: It refers to the failure of the encoder's own components, resulting in its inability to generate and output correct waveforms. In this case, the encoder needs to be replaced or the internal equipment repaired.
2. The encoder connection cable is faulty ...
|
|
The cause of drift in temperature and humidity sensors – Blessing
1. The temperature and humidity sensor will drift during use, which is impossible to avoid.
2. The fundamental reason for the drift is that all pressure sensors are based on the elastic deformation of a kind of material, no matter how outstanding the elasticity of the raw material is, after each elastic recovery, there will always be ...
|
|
Recognition of the number of pulse positions of the encoder
The pulse encoder is a rotary encoder that uses the rotation pulse for signal output, and the main characteristics are the standard shape and diversified shape structure; The internal coding is stable, the signal output qiang, and the pulse value and positioning value are clear. Therefore, when choosing this type of punching encoder, ...
|
|
Auxiliary mechanical device installation method - double blessing
Auxiliary mechanical devices: commonly used are rack and pinion, chain belt, friction runner, rope reeling machinery, etc.
Low-speed end device: installed behind the reduction gear, such as the shaft end of the winch wire rope drum or the shaft end of the next reduction gear ...
|
|
Troubleshooting for coding problems
P+F encoders are devices that compile signals (e.g. bit streams) or data and convert them into signals that can be communicated, transmitted, and stored. The P+F encoder converts angular or linear displacements, the former known as the code disc and the latter into an electrical signal. Therefore, the phenomenon: 1, ...
|
|
The structure of proximity sensor switches – we are blessed
1. Durability
The reason why the switch has such a long life is that the switch acts as elastic from the vertical direction of the elastic membrane. Although millions of peristalsis are carried out after the elastic membrane, because the creep rate is very small, only 0.1 - 0.3m ...
|
|
The role and classification of safety barriers
In electrical intrinsic safety explosion-proof, we generally divide the workplace into explosion-proof areas and non-explosion-proof areas. There is the transmission of electrical energy between the explosion-proof area and the non-explosion-proof area, for example, the switches, buttons, sensors, etc. in the explosion-proof area are connected to the PLC placed in the electrical cabinet in the non-explosion-proof area through wires.
|
|
Precautions during the installation of safety barriers
1. The safety barrier should be installed in a safe place, and the environmental conditions meet the requirements of the "application conditions" in the "Safety Gate Selection Sample".
2. The connecting wires of the intrinsically safe end (blue end) and non-intrinsically safe end circuits of the barrier safety barrier should be laid separately in the wiring slot.
|
|
Instructions for setting up the ultrasonic function
Instructions for setting up the ultrasonic function: The LED shows the setup process. The green light flashes and the target is found; The target did not notice a red ED flash; The connection setting is tucked into place and the T is set. Once the setup process is complete, the sensor works normally.
...
|
|
Contact
working hours
