This document discusses various switches and sensors for integrated control systems. It provides details on magnetic cylinders that use reed switches or magnetic sensors to detect piston positions. Reed switches are small, fast, and easy to install. Solid state proximity sensors can replace limit switches. The document describes the operating principles and specifications of reed switches, solid state sensors, inductive proximity sensors, and vacuum electric and solid state switches. It includes diagrams of typical connections and applications.

1. Switches and Sensors
For integrated control systems
Presemtatiom By Waqar Aziz
waqaraziz370@gmail.com

2. Contents
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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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. End