The basic function

The classification of the sensitive element:

Biology class, based on sensors such as enzymes, antibodies, and hormones

The sensor

Molecular recognition function.

Chemical class, based on the principle of chemical reaction.

Physics class, based on force, heat, light, electricity, magnetic and physical effect, etc.

Often used the sensor function compared with human five sense organs to:

Pressure sensitive, win min, fluid - tactile sensor

Gas sensor, the sense of smell

Photosensitive sensor, vision

Acoustic sensors, hearing

Chemical sensors, sense of taste

Usually according to the basic awareness can be divided into thermal sensor, light sensor, gas sensor, force sensor, magnetic sensor, moisture sensor, acoustic sensor, radiation sensitive element, color sensor and sensor etc. 10 categories (others have sensitive element 46 class).

Common species

Electrochemical sensor

Electrochemical sensor through the react with the gas being measured and produced is proportional to the gas concentration of the electrical signal to work. Can be divided into carbon monoxide sensor, nitrogen dioxide, formaldehyde sensor, etc.

Power sensor

Power sensor is a kind of power will be test parameters (such as current, voltage, power, frequency, power factor and other signals) is converted into dc current and dc voltage and isolate the output analog signal or digital signal of the device. Products comply with GB/T13850-1998. Note: current transducer used to measure true RMS voltage waveform distortion is more serious in the grid voltage or current signal, also can measure the square wave, triangular wave and non-sinusoidal waveform. Letter of LF series power sensor general technical conditions:

Reference standards and rules: GB/T13850-1998

Relative humidity: 93% or less

Level of accuracy: 0.2, 0.5 on the Richter scale are unlikely

Storage conditions: temperature - 40 ~ + 70 ℃, relative humidity of 20 ~ 90%, and without any condensation

Working temperature: - 10 ~ 55 ℃

MTBF: p 30000 h

Resistive sensors

Resistive sensors will be measured, such as displacement, deformation, force, acceleration, humidity, temperature, etc, these quantities into resistance transformation type such a device. Mainly include the resistance strain type, pressure type, heat resistance, thermal resistance, gas sensitive, humidity sensitive a resistive sensor.

Weighing sensor

Weighing sensor is a kind of to gravity into electrical signals and electrical switching device, the force is a key component of the electronic weighing apparatus.

Force can be implemented to electricity conversion there are many types of sensors, common resistance strain type, the electromagnetic type and condenser, etc. The electromagnetic type is mainly used for electronic balance, capacitor used in some electronic crane scale, and most of the instruments or resistance strain type weighing sensor is used for the product. Resistance strain type weighing sensor structure is simple, high accuracy, widely applicable, and can be used in a relatively poor environment. So the resistance strain type weighing sensor has been widely used in instruments.

The temperature sensor

1, at room temperature sensor: room temperature sensor is used to measure the environment of indoor and outdoor temperature, the tube temperature sensor is used to measure the tube wall temperature of evaporator and condenser. Room temperature sensor and the shape of the tube temperature sensor is different, but the temperature characteristic are basically identical. According to the temperature characteristic, the use of beauty room temperature pipe temperature sensor has two types: 1. The constant value of 4100 k B + / - 3%, benchmark resistance of 25 ℃ for sensors

The sensor

Resistance should be 10 k Ω plus or minus 3%. The higher the temperature, the smaller the resistance; The lower the temperature, the greater the resistance. The farther you go from 25 ℃, the corresponding resistor tolerance range is larger; At 0 ℃ and 55 ℃ resistance tolerance about + / - 7%; Above and below 0 ℃ and 55 ℃, for different suppliers, the resistance tolerance will have certain difference. The higher the temperature, the smaller the resistance; The lower the temperature, the greater the resistance. The farther from 25 ℃, corresponding to the greater the resistance tolerance range.

2, exhaust temperature sensor: exhaust temperature sensors used to measure the top of the compressor exhaust temperature, constant value of 3950 k B + / - 3%, corresponding resistance at 90 ℃ for 5 k benchmark resistance Ω plus or minus 3%.

3, modules, temperature sensor, temperature sensor for measuring the frequency conversion module (IGBT or IPM) temperature, the use of thermal model of the head is 602 f - 3500 - f, benchmark resistance is 25 ℃ corresponding resistance Ω 6 k + / - 1%. Several typical temperature corresponding resistance are: - 10 ℃ - (25.897 to 28.623) ─ K Ω; 0 ℃ - (16.3248 to 17.7164) ─ K Ω; ─ 50 ℃ - > (2.3262 2.5153) K Ω; 90 ℃ - Ω ─ (0.6671 0.6671) K.

Many different kinds of temperature sensor, now often use a thermal resistance: PT100, PT1000, Cu50, Cu100; Thermocouple: B, E, J, K, S, etc. Temperature sensor not only sort is various, and combination of various forms, should choose suitable products according to different places.

Temperature measuring principle: according to different resistance resistance, electric potential with the temperature of thermocouple regular changes in principle, we can get the need to measure the temperature.

Displacement sensor

Displacement sensor is also known as linear sensor, displacement sensor is converted to electricity. Displacement sensor is a device that belongs to the metal induction linear sensor is used to convert various measured quantities to power it is divided into inductive displacement sensor, capacitive displacement sensor, photoelectric displacement sensor, ultrasonic displacement sensor and hall displacement sensor.

In the conversion process, there are many physical quantities (such as pressure, flow rate, acceleration, etc.) often need to transform as the displacement, then the displacement transform into electricity. So the displacement sensor is a kind of important basic sensor. In the process of production, displacement measurement generally divided into two physical dimensions and mechanical displacement measurement. Mechanical displacement including linear displacement and angular displacement. According to the measured variable transformation, different kind of displacement sensor can be divided into analog and digital two kinds. Analog type can be divided into physical properties (such as spontaneous electric) and structured two kinds. Displacement sensor is commonly used in the majority with analog structured, including the potentiometer displacement sensor, inductive displacement sensor, selsyn, capacitive displacement sensor and electric eddy current displacement sensor and hall displacement sensor, etc. An important advantage of digital displacement sensor is to facilitate the signal directly into a computer system. This kind of sensor has been developing rapidly, the application is becoming more and more widely.

Fold the pressure sensor

Pressure sensor led is the most commonly used in industrial practice of a sensor, its widely used in various industrial control environment, involved in water conservancy and hydropower, railway transportation, intelligent buildings, production control, aerospace, military industry, petrochemical, oil, electric power, ships, machine tools, pipe, and many other industries.

Liquid level sensor

1, the ball float liquid level sensor

Ball float liquid level sensor ducts, the signal is measured by the magnetic floating ball, unit, the electronic unit, junction box and install.

Generally the proportion of magnetic float is less than 0.5, can float on the surface and move up and down along the measuring tube. Intraductal equipped with measuring element, it can will be under outer magnetic liquid level measurement signal is proportional to the resistance of the liquid level change signal, and converting electronic unit 4 ~ 20 ma, or other standard signal output. The sensor module circuit, has the advantages of acid, moisture, shock, anti-corrosion, internal circuit has permanently within the current feedback circuit and protect circuit, can make the output current is not more than 28 biggest ma, and thus can be reliably protect the power supply and the secondary instrument is damaged.

2, Jane type liquid level sensor

Buoy type liquid level sensor is change the magnetic float to buoy, it is designed according to the principle of Archimedes. Buoy type liquid level sensor is to use small metal film strain sensor technology to measure the liquid level, the position or density. It can be done in the scene button at work regular set operation.

3rd, static pressure and liquid level sensor

Measuring principle of the sensor using the hydrostatic pressure. It usually chooses silicon pressure measured by pressure sensor will be converted to electrical signals, then through amplifying circuit amplification compensation and compensation circuit, and finally to 4 ~ 20 ma or 0 ~ 10 ma current output.

But in the field of sensor devices, industry in our country at present can't meet the needs of the market development. Authorities said that at present domestic sensor chip has been widespread use, such as public transportation card, hotel room card, and pay phone near field and other fields. However, hf and uhf top-end chips, such as the label of the wine and clothes, compared with abroad are still lacking, further technological breakthroughs. In the low temperature, humidity sensors made some progress, but in terms of more high-end sensors, especially that the perception, transmission and processing are integrated into the small size of the chip high-end microelectromechanical systems, there is still a large gap compared with the abroad. Impeded, sensor technology and the future of our country for a period of time in the Internet of things industry promotion cause considerable distress, with foreign product, there may be many in security concerns.

Smart sensors

Intelligent sensor is a sensor which has the function of information process, a microprocessor, has the ability of information acquisition, processing, exchange, is the product of sensors integrated with microprocessor. Smart grid, with a number of intelligent system, not separate individuals, but together with the equipment and technology products. In the monitoring of the first line of sensor devices are small, but absolutely vital. In the smart grid development, using the traditional sensor has not for some power quality and fault location quickly direct measurement and online monitoring. And the use of smart sensors can be directly measured, index, and failure to measure the quality of product (such as temperature, pressure, flow). For example, in order to meet the demand of the smart grid development, our country launched a optical fiber current sensor system, realized the pipeline current sensing system of full digital closed loop control, has good stability and linearity and high sensitivity, met the requirement range in a wide range of high precision measurement. Current, sensors on the smart sensor has become an international research hotspot and frontier. That should be taken to develop the intelligent sensor research, leap-forward development train of thought, is the key to the occupation of the future information technology commanding heights. [1]

Vision sensors

Vision sensors can be divided into 2 d vision sensor and the 3 d vision sensors, two-dimensional vision is basically a camera can perform a variety of tasks. From detecting moving objects to the transmission belt parts localization and so on. 2 d visual have appeared in the market for a long time, and occupy a certain share. Many intelligent cameras can detect parts and help the robot to determine the location of the parts.

Compared with the 2 d vision, 3 d vision is a technology recently. 3 d vision system must have two different point of view of the camera or use a laser scanner. In this way to detect object of third dimension. Also, now there are many applications use the three-dimensional visual technology. Take put parts, for example, use 3 d vision technology to detect objects and create 3 d images, analyze and choose the best way to pick up.

Force/torque sensor

Force/torque sensor for robot to the sense of touch. Robot using force/torque sensors to the magnitude of the end executor. In most cases, force/torque sensor is located in between robots and jig, so that all of the force feedback to the fixture in the monitoring of the robot. A force/torque sensor, like assembly, artificial guide, teach, efforts to limit such application can be realized.

Collision detection sensor

The sensors have a variety of forms. The main application of these sensors is to provide workers with a safe working environment, collaborative robot is most necessary to use them. Some sensors can be a touch recognition system, through the surface of the soft feel pressure, if the perceived stress, will send signals to the robot, limit or stop the robot's movement.

Some sensors can also be directly built in the robot. Some companies use accelerometer feedback, and some current feedback is used. In both cases, when the robot perception to the magnitude of the anomaly, triggering an emergency stop, to ensure safety. But before the robot to stop, you will be hit by it. So the safest environment is completely without collision risk environment, this is the mission of this sensor.

Safety sensor

To make industrial machine to collaborate, people must first find method can ensure the safety of workers. These sensors have a variety of forms, from the camera to the laser, etc., only one purpose, is to tell the robot around the situation. Some security system can be set to when someone appears in certain area/space, the robot will automatically slow running, if people continue to close, the robot will stop working.

The parts detection sensor

In parts pick up application, cannot know the robot gripper correctly grasping the parts. And parts inspection application can provide gripper position feedback for you. For example, if the gripper missed a component, system will detect the error, and a repetitive operation, to ensure that the parts are correct.

Other sensors

There are a lot of sensors suitable for different applications. Such as welding seam tracking sensor.

Tactile sensor is becoming more and more popular. This kind of sensor is usually installed on the gripper used to detect and feel what is the object of prey. Sensors that can detect usually dynamics, and it is concluded that the situation of the power distribution, so as to know the location of the object, so you can control by the force of the actuator at the end of the location and grab grab. There are some tactile sensor can detect the change of the heat.