接近开关检测技术PPT课件

1、.,1,接近开关检测技术,检测技术（一）,inductive proximity sensor,.,2,接近开关,.,3,接近开关,.,4,电感式接近开关,1. 工作原理,电感式接近开关属于一种有开关量输出的位置传感器，它由LC高频振荡器和放大处理电路组成，利用金属物体在接近这个能产生电磁场的振荡感应头时，使物体内部产生涡流。这个涡流反作用于接近开关，使接近开关振荡能力衰减，内部电路的参数发生变化，由此识别出有无金属物体接近，进而控制开关的通或断。这种接近开关所能检测的物体必须是金属物体。,.,5,电感式接近开关,2. 工作流程方框图,.,6,Principle of inductive pr

2、oximity sensor,.,7,Principle of inductive proximity sensor,The detection coil located at the front end of the sensor produces a high-frequency magnetic field as shown in the figure . When an object (metallic) approaches this magnetic field, induced currents flow in the metal, causing thermal loss an

3、d resulting in the reduction or stopping of oscillations. This change in state is detected by an oscillation state sensing circuit which then operates the output circuit.,.,8,NOTE:Only metal detection,It cannot detect non-metals in which current cannot flow, since detection is based on thermal loss

4、due to induced current. Also, metals such as ferrite, which do not allow current flow, cannot be detected.,.,9,Shielded proximity sensor,.,10,Shielded proximity sensor,.,11,Non-shielded proximity sensor,.,12,Type of metal objects and sensing range,The sensing range is specified for the standard sens

5、ing object. If the sensing object is smaller, or is non-ferrous, the sensing range shortens.,.,13,Correlation between sensing object size and sensing range,.,14,电感式接近开关,3. 不同材料的感应性质,.,15,电容式接近开关,1. 工作原理,电容式接近开关亦属于一种具有开关量输出的位置传感器，它的测量头通常是构成电容器的一个极板，而另一个极板是物体的本身，当物体移向接近开关时，物体和接近开关的电容发生变化，使得和测量头相连的电路状态

6、也随之发生变化，由此便可控制开关的接通和关断。这种接近开关的检测物体，并不限于金属导体，也可以是绝缘的液体或粉状物体,在检测较低介电常数的物体时，可以顺时针调节多圈电位器（位于开关后部）来增加感应灵敏度。,.,16,电容式接近开关,2. 工作流程方框图,.,17,电容式接近开关,3. 不同材料的感应性质,介电常数表,.,18,接近开关的接线方式,三线式,.,19,接近开关的接线方式,二线式,.,20,接近开关的使用注意事项,1. 当检测物体较小或较薄时，检测距离要减小。 2. 电感式接近开关的接通时间为50ms，所以在设计中，当负载和接近开关采用不同电源时，务必先接通接近开关的电源。 3.当使

7、用感性负载（如灯、电动机等）时，其瞬态冲击电流较大，可能劣化或损坏交流二线的接近开关，在这种情况下，请经过交流继电器作为负载来转换使用。 4.请勿将接近开关置于200Gauss以上的直流磁场环境下使用，以免造成误动作。 5. DC二线的接近开关具有0.5-1mA的静态泄漏电流，在和一些对DC二线接近开关泄漏电流要求较高的场合下尽量使用DC三线的接近开关。 6.避免接近开关在化学溶剂，特别是在强酸强碱的环境下使用。,.,21,接近开关应用举例,物体的定位,开关位置的确认,连续通过的检测,物体的到位/通过,.,22,接近开关应用举例,产品计数,存在/通过,行程限位,采用电容式开关液位控制,.,23

8、,接近开关应用举例,采用电容式开关上下限控制,料位的控制,.,24,GL-N12 SERIES Low Price Square-shaped Inductive Proximity Sensor It achieves a sensing range of 4mm with a 12mm square-size sensing part.,Application 1,.,25,The inductive proximity sensor detects coins passing by it in a game machine. Since there is no contact, it f

9、eatures high reliability and long life.,Application 1-1,.,26,GD SERIES Metal-sheet Double-feed Detector The high-end GD sensing technology reliably detects double feeds of any metal sheet 0.01mm, or more, thick.,Application 2,.,27,Detecting Missing Tablet Package in Box GD-20 checks if each box cont

10、ains the given number of aluminum tablet packages.,Application 2-1,.,28,Detecting Steel Balls Passing through Metal Pipe The GD series perfectly detects a steel ball passing through a metal pipe, a requirement which has not been met by any beam sensor or proximity sensor.,Application 2-2,.,29,Detect

11、ing Double Feed of Metal Sheets The long sensing range GD-20 can detect objects of different materials up to 10mm thick.,Application 2-3,.,30,GA-10 SERIES GH SERIES Amplifier-separated Micro-size Inductive Proximity Sensor the sensor head is also extremely small, the smallest being just 2.8mm (GH-2S

12、).,Application 3,.,31,Observing Vibration of Parts-feeder The inductive proximity sensor observes the amplitude of vibration.,Application 3-1,.,32,Detecting Screws on Cassette Although the sensor head is very small, it can detect a metal screw reliably.,Application 3-2,.,33,GX-USERIES DC 2-wire Cyli

13、ndrical Inductive Proximity Sensor,Application 4,.,34,Controlling Depth of Drilling The sensor detects the dog-clutch that determines the depth of drilling.,Application 4-1,.,35,GP-A SERIES High Accuracy Eddy Current Type Displacement Sensor,Application 4,.,36,Measuring Gap between Rollers With the high resolution analog proximity sensor GP-A series, fine gap measurement is possible to control the gap between rollers.,Applic