Page 396 - Sensors and Systems - North American Catalog
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Photoelectric Sensors
2
Photoelectric Sensors,
Standard Sensors,
Thru-beam sensors
2
.1
Photoelectric Sensors,
Standard Sensors,
Thru-beam sensors
2
.1
Photoelectric Sensors,
Standard Sensors,
Retroreflective sensors
2
.1
Photoelectric Sensors,
Standard Sensors,
Retroreflective sensors
2
.1
Photoelectric Sensors,
Standard Sensors,
Diffuse mode sensors
2
.1
Photoelectric Sensors,
Standard Sensors,
Diffuse mode sensors
2
.1
Photoelectric Sensors,
Standard Sensors,
Diffuse mode sensors with background suppression
2
.1
Photoelectric Sensors,
Standard Sensors,
Diffuse mode sensors with background suppression
2
.1
Photoelectric Sensors,
Standard Sensors,
Fiber optic sensors
2
.3
Photoelectric Sensors,
Standard Sensors,
Fiber optic sensors
2
.3
394
Germany: +49 621 776-4411
Refer to General Notes Relating to Product Information
Pepperl+Fuchs Group
USA: +1 330 486 0001
Singapore: +65 6779 9091
Copyright Pepperl+Fuchs
Photoelectric Sensors
Introduction
5. Fiber Optic Sensors
Depending on their design, the characteristics of
fiber optic cables are similar to those of a thru-beam
or a diffuse mode sensor.
Thru-beam systems have one fiber optic cable each
for the emitter and the receiver. For diffuse systems,
the light is guided in a single fiber optic cable through
separate emitter and receiver fibers.
The emitter and receiver are housed together in a single sensor
housing. The light beam is guided via a flexible fiber optic cable
(glass or plastic) from the fiber optic sensor to the sensing location.
Due to their small optical surfaces, fiber optic cables are also
suitable for detecting small details in close range. Special fiber
optic cables are used with a coaxial or mixed fiber arrangement
and small fiber diameters (plastic fibers: a few hundred µm, glass
fibers: typically 50 µm).
The large opening angle at the light exit of the fiber optic cable
(approx. 70°) also enables it to be used to achieve shorter detection
ranges than standard photoelectric sensors or light sensors; if
necessary, these can be increased using suitable lens attachments.
Glass or plastic?
When choosing a suitable fiber optic cable, users can choose
between plastic or glass fiber optic. The characteristics of both
these materials are briefly outlined as follows.
•
Plastic fiber optics
consist of a single PVC-sheathed fiber. As the fiber optic cable
material is lightweight and very flexible, it can be used on
machines with moving parts. One advantage in particular is the
individual assembly of the fibers. The standard length is 2 m.
The cutter, provided with the fiber-optic cable, can be used to
easily shorten the fiber optic cable to the length required for the
application. Two different fiber diameters and a range of different
fiber heads are available to choose from.You are sure to find a
type to suit your application.
•
Glass fiber optics
consist of many individual fibers, each with a diameter of
approx. 50 µm. Depending upon the application, sheathing is
available in stainless steel, PVC, metal and silicone, or silicone.
Due to the low optical attenuation of glass fibers compared to
plastic fibers, larger sensing ranges are possible. The robust
mechanical design of the stainless steel sheathing means that
the cables can be used at temperatures of up to 300 °C.You
will find a suitable solution for your application from the range of
fiber heads, each of which can be combined with the sheathing
materials.
6. Distance Measurement Sensors
These devices measure the time for light to travel
from the sensor’s emitter to an object and back to
the sensor’s receiver. This time interval is used to
determine the distance to the target object.
Pulse Range Technology (PRT):
Pulse Ranging Technology is a direct method of
measurement. The distance is determined based
on the time interval ∆t for light to travel from the
emitter to the target object and back to the receiver.
A sequence of very short, high-intensity, laser light
pulses is generated from the emitter. These pulses
propagate at the speed of light to the target object or reflector and
are returned to the receiver. The time of flight of these light pulses
are captured and very accurately measured. Based on this time
interval, the distance can be accurately determined. (See the figure
below.) The high-speed timer unit and microprocessor then send
an output signal that is proportional to the distance to the target
object.
e 04.04.2008
Overview of the function princi
5. Light grids for clear glass detection
The devices of the PR and LG series
are high resolution light curtains used to
detect very small non-position guided
objects.
By using special low-noise receiver
stages and a smart evaluation algorithm even trans-
parent objects can be safely and reliably detected.
Crossed bea evaluation:
Every transmitter has a line of sight to every receiver.
This results in a very high sensor resolution.
Automatic calibration:
After the power supply is turned on (model number -
W), or after calibration input has been externally acti-
vated (model number -F), the sensor automatically
calibrates itself. In this process, each individual trans-
mitter-receiver route is individually calibrated.
Example PR16:
16 transmitters, 16 receivers with crossed beam eval-
uation. 256 light beams are internally calibrated and
evaluated separately. In addition, the switching limit of
the individual transmitter-receiver routes is subject to
continuous control during operation within a certain
bandwidth. This means that at certain time intervals
the sensor compares the value that has been saved
with the level of reception that is actually being mea-
sured at that moment.
If these two values should differ over the course of
time (because of slight smudges or minor misadjust-
ment), the emitter threshold of each individual light
path is redetermined. This makes it possible to ensure
that highly transparent objects will always be detect-
ed, even in harsh industrial conditions.
6. Optical data couplers
Optical data couplers are used for the
cable-free transmission of information
from point A to point B. One of the two
optical data couplers can be moved in
an axial direction. For the transmission
via the optical path, the FSK method (Frequency Shift
Keying) is used. In other words, the bit information is
coded in the carrier frequency.
The transmitted signal is shifted between two frequen-
cies f1 and f2 that correspond to either logic bits 0 or
1. Narrow band filtering, used on the receiver side to
convert the data back to logic, prevents extraneous
signals from corrupting the transmitted data. The data
transmission is unaffected by signal level variation.
Our program cont
as w ll as serial
• Parallel data tr
An optical data
tionally. To do t
verted into a se
applied to the p
modulation, whi
transfer the bin
• Serial data tran
Our serial optic
method. The da
transferred with
exported again
Many devices
able in a versio
es are always u
of parallel trans
cross-talk with t
excluded.
7.
reliability
The new generati
the features you
install, and reliabl
All photoelectric
in this catalog ha
• highly visible L
• Green LED for
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• Cross-talk imm
f
1
log „0“
Sensors Catalogue.book Seite 303 Freitag, 4. April 2008 9:58 09
Date of issue 31.03.2008
Subject to reasonable modifications due to technical advances.
Pepperl+Fuchs Group • Tel.: Germany +49 621 776-0 • USA +1 330 4253555 • Singapore +65 67799091
(e.g. start and stop positions).
The "zero point" of the analog output can be selected
to allow the user to reference the electrical zero to a
known mechanical position (e.g. mounting and align-
ment). This significantly facilitates both mounting of
the PMI360D-F130... an subsequent calibration dur-
ing commis ioning.
Mounting the BT-F130-A target on the sensor housing
bore enables position sensing. This target rotates in
the central bore of the PMI360D-F130 and contains
the metal insert required for position sensing. It is opti-
mally designed for the mecha ical conditions of
valves or rotary actuators. The BT-F130-A target can
be omitted. If you choose to do so, a metal target must
be secured to the sensor housing bore. This metal tar-
get must meet the material, dimensional and distance
requirements of the PMI360D-F130.
2 L ser displacement devices
On method for indirect distance mea-
suring is the phase correlation method.
This is used i our EDM series of sen-
sors. The distanc is cal ulated via the
phase displacement between the
transmitted and th reflected int nsity modulated light.
The transmitter generates a constant sinusoidal inten-
sity modulated light with a modulation frequency of
several MHz. The light reflected by the reflector or the
object reaches the receiver with the phase displace-
ment
∆ϕ
(see fig.). The downstream phase indicator
provides an output signal proportional to the distance.
light impulses.
same time. Afte
completed, an op
impulse and sto
read represents t
Depending on th
measuring range
VDM series of se
to 240 m.
3 WCS pos
For positioning o
offers the proven
The position enc
lar in systems wi
pa hs and under
dirt, dust, aggres
With measuring
able for position
• warehouse an
• studio technolo
• crane positioni
• galvanic equip
• elevators
Light transit time
∆
t
Start
Stop
Timer unit
Emitted light
Intensity
Receive
sue 31.03.2008
7
Positioning / Position sensing
PMI360D- F130...
The PMI360D-F130...
inductive positi n mea-
suring system is a high-
precision measuring
sys em for non-co tact
reco di g of th position
of rotary actuators an
valves.
Because of its flexible
configuration, it is also suitable for universal sensing
of rotary motions around a fixed cent r of rotation in all
fields of mechanical, system, and apparatus engineer-
ing.
In addition to its 4 ... 20 mA analog output, the
PMI360D-F130... has two independently configurable
switching outputs prov ding wo impor nt positions
(e.g. start and stop positions).
The "zero point" of the analog output can be selected
to allow the user to reference the electrical zero to a
known mechanical position (e.g. mounting and align-
ment). This significantly facilitates both mounting of
the PMI360D-F130... and subsequent calibration dur-
ing commissioning.
Mounting the BT-F130-A target on the sensor housing
bore enables position sensing. This target rotates in
the central bore of the PMI360D-F130 and contains
the metal insert required for position sensing. It is opti-
mally designed for the mechanical conditions of
valves or rotary actuators. The BT-F130-A target can
be omitted. If you choose to do so, a metal target must
be secured to the sensor housing bore. This metal tar-
get must meet the material, dimensional and distance
requirements of the PMI360D-F130.
2 Laser displacement devices
One method for indirect distance mea-
suring is the phase correlation method.
This is used in our EDM series of sen-
sors. The distance is calculated via the
phase displacement between the
tr n itted and th reflected intensity modulated light.
The transmitter generates a constant sinusoidal inten-
sity modulated light with a modulation frequency of
several MHz. The light reflected by the reflector or the
object reaches the receiver with the phase displace-
ment
∆ϕ
(see fig.). The downstream phase indicator
provides an output signal proportional to the distance.
Another method is time-of-flight. This method is used
by our VDM laser distance measuring devices. This
represents a direct distance detection based on the
runtim measurement. A m asuring laser emits short
light impulses. An inte nal counter is tarted at t e
same tim . Aft r the measuring dis ance has be n
completed, an pt cal sensor eceives he arriving light
impulse and stops the counter. The counter value
read represents the completed measuring distance.
Depe ding on the sensor and refle tor used, different
measuri g ranges can be observed. For example the
VDM series of sensors have a mea uring range of up
to 240 m.
3 WCS position encoding system
For positioning over long distances, Pepperl+Fuchs
offers the proven WCS position encoding system.
The position encoding system WCS excels in particu-
lar in systems with turn , ju ctions as well as inclined
paths and un er difficult ambie t conditions such as
dirt, dust, aggressive vapors.
With measu ing distances of up to 327 meters it is suit-
able for position detection in:
• warehouse and conv yor system
• studio technology
• crane positioning
• galvanic equipment
• elevators
Received light
Emitted ligh
Phase shift
∆ϕ
Intensity
t
Light transit time
∆
t
Light transit time
∆
t
Start
Stop
Timer unit
Micro-
controller
Interface
Emitted light
Time
Time
Intensity
Received light
Positioning systems
