Pomiar prędkości
l� prądnice tachometryczne prądu stałego
l� prądnice tachometryczne indukcyjne
l� prądnice tachometryczne synchroniczne
Prądnica tachometryczna prądu stałego to mała prądnica prądu stałego ze
wzbudzeniem obcym, lub ze wzbudzeniem magnesem stałym.
W prądnicach tachometrycznych prądu stałego stosowanie szczotek węglowych
jest niewskazane ze względu na znaczne wartości napięcia przejścia Up między
szczotką a wycinkiem komutatora. Powoduje to przesunięcie charakterystyki
wyjściowej i wprowadza błąd nieliniowości tej charakterystyki.
Pomiar prędkości czujnikiem
indukcyjnym
Czujniki indukcyjne
Koło zębate zmienia wartość indukcyjności -
zmiany napięcia wyjściowego (ich częstotliwość
jest proporcjonalna do prędkości obrotowej.
Podobny rezultat można uzyskać stosując
elementy optoelektroniczne.
Transoptory
(czujniki optoelektroniczne)
W tym przypadku należy wyeliminować zakłócenia od innych
z
ródeł światła (migotanie świetlówek, żarówek itp.). Możemy
wykorzystać również zakres fal podczerownych.
W obu powyższych przypadkach, aby móc współpracować z
analogowym regulatorem prędkości należy zastosować
przetwornik f/U (częstotliwość - napięcie).
Capacitive proximity switches
l�The sensing face of a capacitive sensor
is formed by two concentrically arranged
metal electrodes that are equivalent to
the electrodes of a capacitor.
l�The electrode surfaces A and B are
connected into the oscillator which does
not oscillate when the surface is free.
l�When an object approaches the active
face of the sensor, it enters the electric
field in front of the electrode surfaces
and causes a change in the coupling
capacitance. The oscillator starts to
oscillate; the amplitude is recorded by
an evaluation circuit and converted into
a switching command.
Capacitive proximity switches
Capacitive proximity switches
l�Contain the same functional units as inductive
sensors
l�Instead of coil an capacitor is used
l�These proximity switches detect conducting and
non-conducting solids, powders, liquids (almost
any materials).
Recognition of milk in
cartons
Level control for bulk
material in vessel
Photoelectric sensors
l�Respond to a change of the intensity of light falling upon them
l�Applications include
Ą�Detecting the presence of elements
+
Ą�Recognition of elements,
Ą�Level and dimensions measuring
l�Three distinct modes of operation
E
Ą�Bariera optyczna
Ą�Refleksyjne (retroreflective)
Ą�Odbiciowe (diffuse sensor), rozproszeniowe
l�Used infrared LEDs
l�Light signal is modulated to overcome the problem of
disturbation and low emission
Proximity switches
l� Proximity switches involves the reflection from the object itself
l� Operate with infrared, red or laser light.
l� Recognize all objects independent of their constitution, whether metal, wood
or plastic.
l� Different colors or differences in contrast can even be detected using special
devices such as the color sensor or printed mark reader.
l� Extremely exact clearance measurements and position checks are possible
with the analog laser.
l� The sensors can be adjusted rapidly and conveniently using Teach-In or
potentiometers.
Photoelectric sensors
Opposed sensors
l�Thru-beam sensors comprise an
emitter and a receiver.
l�The receiver evaluates the incoming
light to clearly separate it from the
ambient light and other light
sources.
l�Any interruption of the light beam
between emitter and receiver
causes the output to switch.
Czujniki optyczne bariery
Czujniki optyczne
W systemie refleksyjnym nadajnik i odbiornik są w tej samej obudowie
Strefa promieniowania
NADAJNIK
Strefa aktywna
reflektor
ODBIORNIK
Sn
Photoelectric sensors
Retroreflective sensors
l�The light from the emitter diode is
focused through a lens and
directed by a polarization filter to a
reflector
l�Part of the reflected light passes
through another polarization filter
and reaches the receiver.
l�The filters are selected and aligned in such a way that only the
light reflected from the reflector reaches the receiver and not
the light reflected from other objects within the beam range.
l�An object that interrupts the light beam from the emitter through
the reflector to the receiver causes the output to switch.
Proximity sensors
Diffuse sensor (energetic sensor)
l�The light from the emitter falls on an object
and is reflected in a diffuse pattern.
l�Part of this reflected light reaches the
receiver located in the same device.
l�If the intensity of the received light is
sufficient, the output is switched.
l�The sensing range depends on the size and
color of the object involved as well as its
surface texture.
l�The sensing range can be varied within a
wide range by means of the built-in
potentiometer.
l�The energetic sensor can therefore also be
used to detect different colors.
Proximity sensors
Diffuse sensor with background
suppression (tłumienie)
l�can detect objects up to a specific
sensing range.
l�All objects beyond this range are
suppressed.
l�The focus level can be adjusted.
l�The background is suppressed due to
the geometric constellation between
the emitter and the receiver.
Czujniki optyczne - laserowe
" Najczęściej czujniki laserowe są stosowane w przenośnikach i w przemyśle
związanym z opakowaniem ze względu na 2 swoje właściwości (duża strefa
działania oraz małe rozmiary wyemitowanej wiązki):
" ochrona stref  granicznych wokół maszyn średnio niebezpiecznych: roboty,
paleciarki; w tych zastosowaniach duży zasięg i widoczność wiązki są
podstawowymi atutami;
" nadzór wzdłuż przenośników: ze względu na czujnik laserowy typu XU2 z
powodzeniem może zastąpić 2 czujniki pracujące w systemie bariery optycznej.
Czujniki optyczne
Programowalny czujnik
High-speed, High-accuracy CCD Laser
Displacement Sensor
Ultra-high speed 50 kHz
High accuracy ą0.02%
Wide measuring range 9 to 1000 mm
Laser scanner
l� is an optical, non-contact area scanner, which is
principally designed for protecting personnel
l� the laser scanner generates light pulses that are
scattered throughout the operating range by an
integrated rotating mirror.
l� If objects or persons enter the field, it evaluates
the reflected light pulses and calculates the exact
position coordinates continuously on the basis of
the light propagation time.
l� If the defined personnel protective field is
penetrated, the laser scanner stops the machine
immediately (within the system response time).
l� The Stop function is reset when the protective
field is free again either automatically or following
acknowledgement (depending on the operating
mode).
Czujniki wizyjne
Ultrasonic sensing
Just like bats: Even when it is completely dark, their perfect auditory
system analyzes the echo returning from the ultrasonic sounds which
they emit to orientate.
Independent of the brightness, they can detect different materials, forms
and colors  even transparent substances; the same goes for the
widest range of consistencies  from solid and liquid up to powders.
Sensing range (cm  m)
Ultrasonic sensing
l�The main parameters that can be set are:
Ą�Lower and upper limit of the operating range
Ą�Switching function NO or NC
Ą�Analog characteristic, rising or falling
Ultrasonic sensing
detects every object on the
conveyor line  when filling
bottles as well as in, special
machinery construction.
Filling level,
detecting stacking heights or
sensing diameters  detects everything:
Paper, plastic, textiles, transparent objects.