Switches and sensors

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Switches and sensors off all types used For integrated control systems

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Switches and sensors

  1. 1. Switches and Sensors For integrated control systems Presemtatiom By Waqar Aziz waqaraziz370@gmail.com
  2. 2. Contents         Introduction Magnetic cylinders Reed switch principle Sensor principle QM/45/* range QM/33,34,134 range M/40,41,42 range Inductive proximity sensors  Cable capacitance Vacuum electric switch  Vacuum electronic switch  Click the section to advance directly to it
  3. 3. Introduction  Typical electro-pneumatic systems consist of:  magnetic cylinders and solenoid valves for dynamic power  reed switches and sensors for feedback  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 solid state sensors are small, fast, easy to fit and adjust. They simplify installation on to the machine application
  4. 4. Magnetic cylinders  Magnetic cylinders have a band of magnetic material inset around the circumference of the piston  The polarity is in parallel with the 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
  5. 5. Reed switch principle  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
  6. 6. 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 diode for an inductive load +V load sensor N S 0V
  7. 7. 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
  8. 8. 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 Protection diode for d.c. only QM/45/RAP 0V Blue Brown Coil +V
  9. 9. Reed switches  Reed switch with l.e.d. indicator  Three wires emulating p.n.p. sensor  Current sourced on the black wire to the coil  Resistor protects l.e.d. from over voltage Protection diode QM/45/LAP 0V Black Coil Blue 0V Brown +V
  10. 10. 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.  10 to 240V a.c./170V d.c. 10 W/VA maximum  Shown with VDR for suppression a.c. or d.c. QM/45/LAP Voltage dependant resistor (VDR) 0V Blue Brown Coil +V
  11. 11. 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 Protection diode +V QM/45/LAN Black Load Brown +V Blue 0V
  12. 12. 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 QM/45/EAP brown +V blue 0V coil pnp black protection diode 0V
  13. 13. Reed switches 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
  14. 14. Reed switches  Plain reed switch brown +V QM/33  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. Load blue QM/33/C black blue 0V Load Load 0V 0V brown +V QM/34/P QM/34/N brown +V blue 0V Load black 0V blue 0V brown +V Load black +V brown +V QM/34/S blue Load 0V
  15. 15. Solid state sensors  Output p.n.p. fixed cable  Output p.n.p. plug-in cable QM/134 pnp  Output n.p.n. fixed cable  Output n.p.n. plug-in cable brown +V blue 0V black 1 3 QM/134/P pnp 4 QM/134/N black npn black QM/134/X 0V 4 Load +V blue 0V brown +V 3 npn Load blue 0V brown +V 1 QM/134/N/P 0V brown +V blue 0V  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 Load black Load +V brown +V blue 0V black Load 0V
  16. 16. 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.
  17. 17. 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.
  18. 18. Reed switches brown +V  Two wire with l.e.d. 10 to 240V a.c./170V d.c.  With high temperature cable  With very flexible polyurethane cable  Two wire with l.e.d. and plug in cable 10 to 60V a.c./74 d.c.  Change-over contacts without l.e.d. M/40 blue TM/40 Load 0V M/40/*/PU brown +V M/40/P Load M/40/C black blue brown Load Load 0V blue 0V 0V +V
  19. 19. Solid state magnetic switches  Output n.p.n. 10 to 30V d.c. 200 mA maximum  Output p.n.p. 10 to 30V d.c. 200 mA maximum  Output p.n.p. with very flexible polyurethane cable  Output p.n.p. with plug-in cable M/41 M/42 blue 0V brown +V npn black pnp black 1 3 pnp +V brown +V blue 0V M/42/*/PU M/42/P Load 4 Load 0V brown +V blue 0V black Load 0V
  20. 20. Inductive proximity sensors  Sense the presence of metal near the M/P28473 tip  Used as a limit switch for mechanical parts  Depending on type: M/P70104/1&2  Range 0.8 to 2 mm M/P70104/3&4  Switching frequency 500 to 2000 Hz  With or without l.e.d. M/P70104/5&6  10 to 30 or 6 to 30 V d.c.  Normally closed or normally open M/P70104/7&8 p.n.p. output M/P70104/9 brown pnp +V blue black Load 0V brown pnp +V blue black Load 0V
  21. 21. Cable capacitance  Long leads above the standard cable length become a long thin capacitor +V (equivalent circuit ) 0V  Closing the switch shorts the capacitor, the instant high current overloads and damages the switch contacts  Fit an inductor (470µH) close to the switch. This damps the surge but has a low steady state resistance +V 0V L 470µH +V Load Standard leads Extended leads 0V
  22. 22. Vacuum electric switch  Switches contacts at a vacuum set point  Adjustable between zero and 0.8 bar absolute  Normally open and normally closed versions  Up to 250V a.c./d.c. 2A max  Repeatability + or - 0.1 bar  Reset differential 0.2 bar
  23. 23. Vacuum solid state switch  Analogue output 1 to 5 V proportional to vacuum  Solid state switched output at vacuum set point  Adjustable reset hysteresis  Adjustable from zero to 1bar absolute  Output n.p.n. or p.n.p. vesions set point hysteresis U +V dc supply (brown) Analog out (white) Switch out (black) Load 0 V (blue) U +V dc supply (brown) Analog out (white) Switch out (black) Load 0 V (blue)
  24. 24. End

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