short coz-limit switch.ppt

7/23/2019 short coz-limit switch.ppt

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Discrete – LimitDiscrete – Limit

SwitchesSwitches



Application

Limit switches are used to detect:

absence or presence of objects

passing

positioning

end of travel (limit)



Symbol ( IEC ) and Composition

NO NC

S1

1

S1

1



A mechanical sensor

OPERATING PRINCIPLES

For detection, the object needs to

actuate the operator which in turnschange the contact from NO toclosed, or from NC to opened



OPERATING PRINCIPES

!FO"! #F$!"

!"#

$ac

!"#$ac



COMPOSITION



%&estion ' o to choose the ri*htsensor +



Positive Opening.

$he operation of a limit switch mustcompl% with standard &!C '*+*

-ection .: All the normally closed contact

elements of the switch can bechanged with certainty to the

o!en !osition "no fle#ible lin$between the mo%ing contacts andthe o!erator of the switch to whichan act&ating force is a!!lied'



The dis!lacements!eed of themo%ing contacts

is inde!endent tothe s!eed of theo!erator( S&itablefor low s!eed

act&ators

The dis!lacements!eed of themo%ing contacts

is e)&al or!ro!ortional tothe s!eed of theo!erator(

Snap Action Slo ,rea-

Characteristics



Operator & Detection Movement

Pl&nger Roller * Pl&nger




lever




/ultidirectional



.irin* dia*ram

/

"

"0$ ac

1

!

A1

A!

#$ ac

S1

1

231

231

!

S!

1

45

46

S/

1

!

S"

short coz-limit switch.ppt

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