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1、Switches and Sensors,For integrated control systems,气动技术双语电子教案 吴洪明Chapter 8 Sensor,WUHAN UNIVERSITY OF TECHNOLOGY LOGISTICS ENG. DEPT. 武汉理工大学 物流工程学院,Contents,Click the section to advance directly to it,Magnetic cylinders,Reed switch principle,Sensor principle,QM/45/* range,QM/33,34,134 range,M/40,41
2、,42 range,Inductive proximity sensors,Vacuum electric switch,Vacuum electronic switch,Cable capacitance,Introduction,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Introduction,Typical electro-pneumatic systems consist of: magnetic cylinders and solenoid valves for dynamic power reed switches and sensors for feedba
3、ck electronic logic for control Reed switches and solid state magnetic sensors are fitted to cylinders to feedback particular positions of the piston,Solid state proximity sensors can be used to replace limit switches, for detecting the position of mechanisms or other moving parts Reed switches and
4、solid state sensors are small, fast, easy to fit and adjust. They simplify installation on to the machine application,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Magnetic cylinders,Magnetic cylinders have a band of magnetic material inset around the circumference of the piston The polarity is in parallel with th
5、e axis of the cylinder The barrel is made of non ferrous material By placing reed switches along the outside of the cylinder, signals can be given at the extreme and intermediate positions of stroke,Click the illustration to start and stop animation,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Reed switch princip
6、le,A basic reed switch consists of a small glass tube containing soft iron contact reeds normally sprung open When a magnetic field is in range the reeds will become magnetic The ends will be of opposite polarity and pull themselves together,Click the illustration to start and stop animation,气动技术双语电
7、子教案 吴洪明Chapter 8 Sensor,Magnetic sensor principle,In the presence of a magnetic field the magnetoresistive sensor has a lower resistance. This causes current to be drawn from the base of the transistor turning it on The circuit incorporates l.e.d., reverse polarity protection diodes and suppression
8、diode for an inductive load,sensor,load,+V,0V,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Reed switches and sensor,Slim cylindrical housing PVC cable in 2 or 5 metre lengths Optional very flexible polyurethane cable With or without l.e.d. indicator Range of four reed switches and one solid state sensor,气动技术双语电子教
9、案 吴洪明Chapter 8 Sensor,Reed switches,Basic reed switch Shown connected to a relay or solenoid coil with diode suppression for d.c. application 10 to 30V a.c./d.c. Maximum switching power 10 W/VA,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Reed switches,Reed switch with l.e.d. indicator Three wires emulating p.n.p
10、. sensor Current sourced on the black wire to the coil Resistor protects l.e.d. from over voltage,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Reed switches,Reed switch with l.e.d. indicator and two wires only Current sourced on the black wire to the coil Zener diode provides small voltage drop to turn on l.e.d.
11、10 to 240V a.c./170V d.c. 10 W/VA maximum Shown with VDR for suppression a.c. or d.c.,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Reed switches,Reed switch with l.e.d. indicator Three wires emulating n.p.n. sensor Current sunk on the blue wire from the load to 0V Resistor protects l.e.d. from over voltage,气动技术双语
12、电子教案 吴洪明Chapter 8 Sensor,Solid state switches,Solid state magnetically operated p.n.p. output Used for applications where vibration levels are unsuitable for reed switches Magnetoresistive sensor element Sensor on l.e.d. indicator 10 to 30 V d.c. 200mA maximum,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Reed swi
13、tches and sensors,Neat cylindrical housing with fixed or plug-in cable Straight or 90o plug-in connector cables Optional: very flexible polyurethane cable or high temperature (150oC) silicon cable With or without l.e.d. indicator Wide range of reed switches and solid state sensors,气动技术双语电子教案 吴洪明Chap
14、ter 8 Sensor,Reed switches,Plain reed switch Plain change-over reed switch Three wire reed switch with l.e.d., emulating p.n.p. sensor and plug-in cable Three wire reed switch with l.e.d., emulating n.p.n. sensor Two wire reed switch with l.e.d.,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Solid state sensors,Out
15、put p.n.p. fixed cable Output p.n.p. plug-in cable Output n.p.n. fixed cable Output n.p.n. plug-in cable Pulse stretcher. Output p.n.p. fixed cable. When operated and released output will remain on for a further 30 ms approximately. Suitable for part stroke position on fast operating cylinders,1,black,Load,0V,QM/134,QM/134/P,QM/134/N,QM/134/N/P,QM/134/X,气动技术双语电子教案 吴洪明Chapter 8 Sensor,Reed switches and sensors,Low profile with dove tail slide for cylinders with integral track in extruded body Screw tightening Fixed cable or plug-in connector cables straight or 90o With or without l.e.d.,
