For integrated control systems

Switches and Sensors

Presemtatiom By Waqar Aziz

waqaraziz370@gmail.com

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/40,41,42 range Inductive proximity

sensors

Vacuum electric switch Vacuum electronic switch

Cable capacitance Introduction

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

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

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

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

sensor

N S

load

+V

0V

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

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

Brown

Blue

+ V

0 V

Coil

Protection diodefor d.c. only

QM/45/RAP

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

BlueCoil

Black0 V

Brown + V

0 V

QM/45/LAP

Protection diode

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.

Blue Coil

0 V

Voltage dependant resistor (VDR)

Brown + V

QM/45/LAP

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

Brown

Black Load

Protection diode

+ V

Blue 0 V

+ VQM/45/LAN

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

brown

blue

black

pnp

+V

0V

0V

coil

protection diode

QM/45/EAP

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

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.

blue

brown +V

Load

0V

brown +V

blue black

0V 0V Load

Load

brown +Vblue 0V

Load+V black

brown +V

blue Load 0V

QM/33

QM/33/C

QM/34/P

QM/34/N

QM/34/S

brown +Vblue 0V

Load0V black

Solid state sensors

Output 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

brown +Vblue 0V

blackpnp

Load 0V

13

4pnp

brown +Vblue 0V

black Load 0V

1

brown +V

blacknpn

Load +V

blue 0V

3

4npn

brown +V

black Load +V

blue 0V

black Load 0V

brown +Vblue 0V

QM/134

QM/134/P

QM/134/N

QM/134/N/P

QM/134/X

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.

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.

Reed switches

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.

+V

blueLoad 0V

brown

brown

blue black

0V0VLoad

Load

+V

M/40

M/40/P

M/40/C

brown

blue Load 0V

+V

TM/40

M/40/*/PU

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

brown +Vblue 0V

blackpnp

Load 0V

brown +V

blacknpn

Load +V

blue 0V

M/41

M/42

13

4pnp

brown +Vblue 0V

black Load 0V

M/42/*/PU

M/42/P

Inductive proximity sensors

Sense the presence of metal near the tip

Used as a limit switch for mechanical parts

Depending on type:Range 0.8 to 2 mmSwitching frequency 500

to 2000 HzWith or without l.e.d.10 to 30 or 6 to 30 V d.c.Normally closed or

normally open p.n.p. output

brown

blue

black

pnp

Load 0V

+V

brown

blue

black

pnp

Load 0V

+V

M/P28473

M/P70104/1&2

M/P70104/3&4

M/P70104/5&6

M/P70104/7&8

M/P70104/9

Cable capacitance

Long leads above the standard cable length become a long thin capacitor (equivalent circuit )

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

L + V

0 VLoad

+ V

0 V

+ V

0 V

Extended leadsStandard leads

470µH

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

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

+V dc supply (brown)Analog out (white)Switch out (black)0 V (blue)

Load

+V dc supply (brown)Analog out (white)Switch out (black)0 V (blue)

Load

U

U

set pointhysteresis

End