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Consider the General Notes on the Information in the Pepperl+Fuchs Product Catalogs
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Additional Information
Pulse stretching
Timer function that is used to delay the
switching time, provided it is shorter than the
pulse stretching value.
⇒ Timer function
Push-pull output
The maximum high signal is calculated from
the supply voltage minus the voltage drop
specified in the data sheet.
The low signal corresponds with the
reference potential.
Q
uality assurance
The standards DIN ISO 9000-9004 (EN
29000-29004)
regulate the quality assurance
(
QA) of products and services.
Pepperl+Fuchs GmbH is certified according
to DIN ISO 9001.
R
ated operational current
This value specifies the maximum load
current during continuous operation.
Rated operational voltage
The rated operational voltage is specified
with maximum and minimum values for
supply voltage,
e.g., Ue = 10 VDC to 30 VDC.
Safe operation of the sensor is guaranteed
within this range.
Red light
Visible light with wavelengths between 630
and 780 nm. Red light end diodes operate,
e.g., with l = 660 nm.
Reference axis
Ideal line on which the emitter and
receiver (thru-beam sensor) or emitter and
object/reflector (diffuse mode sensor or
retroreflective sensor) face each other.
Photoelectric sensors:
In the case of a thru-beam sensor, the
reference axis is the same as the optical axis
of the lens
in the case of a diffuse mode sensor or
retroreflective sensor it is the center line
between the optical axes of the transmitter
and receiver lens.
Ultrasonic sensors:
The reference axis on single-head systems
is the same as the line of symmetry for the
sound beam
on dual-head systems it is the center line
between the sound beam axes of the emitter
and receiver.
Reflection
In general, a reflection is a throwback of
waves on the boundary between two media.
There are three types of reflection:
Mirroring: reflection where virtually the entire
incident radiant power is reflected and for
which the angle of incidence = angle of
reflection.
Largely directed reflection: mirroring with
diffuse portion, e.g., for rough object
surfaces.
Diffuse reflection: reflection where the
incident radiant power is reflected equally in
all directions.
The way in which an ultrasonic wave is
reflected depends on the ratio between the
sound wavelength and the roughness of the
object‘s surface.
⇒ Section Notes on mounting and operating
Reflectivity
Depending on an object‘s surface structure
and texture, it will reflect ultrasonic waves
well or poorly, directly or diffusely. The
unreflected portion is absorbed or emitted.
Reflection tables for common materials can
be used to estimate the achievable detection
range for diffuse mode sensors.
Reflector
A reflector is a level plate with good
reflective characteristics, which is positioned
perpendicular to the propagation direction of
the sound waves within the detection range.
The reflector is used as a reference object
for ultrasonic diffuse mode sensors that are
used in retroreflective mode.
⇒ Sensor principle
Reflector range
Ultrasonic sensors:
Range within which the ultrasonic sensor‘s
reflector must be installed in retroreflective
mode in order to be safely detected. The
reflector range spans from the end of
the reflector blind zone to the end of the
detection range.
Photoelectric sensors:
Range within which the retroreflector of a
retroreflective sensor must be installed in
order to be safely detected. The reflector
range spans from the end of the retroreflector
blind zone to the end of the detection range.
Repeat accuracy
⇒ Repeatability
Repeatability
(
also: repeat accuracy)
This is determined during an eight-hour
test at 23 +5 °C and under rated operational
voltage. The difference between two
operating distances must not exceed 10% of
the actual operating distance.
Residual ripple
The AC voltage (peak to peak) that is
superimposed over the operating DC voltage
is specified as a percentage of the arithmetic
average value. Pepperl+Fuchs GmbH
sensors feature max. 10% residual ripple and
comply with standard EN 50008.
Resolution
Smallest change in the measured quantity
that can be detected and shown by a
measuring sensor.
Response time
The shortest possible time between
two switch outputs. The response time
corresponds with half the reciprocal value of
the switching frequency.
Retroreflective area sensor
A retroreflective area sensor contains several
transmitters and receivers in one enclosure
with a reflector positioned opposite, forming
a continuous wide or high detection area
over the relevant detection range.
When the light beams in the detection area
are interrupted by an object, the switching
element function is triggered.
These sensors are suitable for reliable and
complete object detection irrespective of the
object‘s shape, surface, and position without
incorrect switching. If the object‘s shape or
position changes, you do not need to realign
the sensors.
Retroreflective sensor
Consists of an active device with an
integrated light source and receiver as well
as a passive reflector from which the light is
reflected.
⇒ Section Mounting and functional principle of
optical sensors
Retroreflective sensor (type R)
Ultrasonic sensor in retroreflective mode.
A highly reflective object within the detection
range is used as a reference. Poorly reflective
objects that appear in the detection range can
be safely detected in this operating mode.
⇒ Section Sensor principle
Retroreflector
Retroreflectors (also referred to as triple
mirrors) reflect the incoming light parallel
to the direction of incidence. They can be
rotated up to a certain angle in relation to the
reference axis without restricting the function
of a retroreflective sensor.
Retroreflector blind zone
Zone in front of a retroreflective sensor where
the retroreflector is not detected.
Reverse polarity tolerant
A reverse polarity tolerant sensor is
guaranteed to operate irrespective of the
polarity of the supply voltage.
Ring register, standard 0 mode
The same single position value is often
required multiple times by the evaluation
electronics. For this, a 51-bit long start
sequence is sent to the multiturn absolute
rotary encoder instead of a 25-bit start
sequence, for example. If the absolute
rotary encoder is in ring register mode, the
same position value is transferred twice in
succession. The control unit can then check
for consistency in order to filter out transfer
errors, e.g., caused by EMC faults.
In standard 0 mode, zeros are provided as of
the 26th cycle.
Ripple
The AC voltage (peak to peak) that is
superimposed over the operating DC voltage
is specified as a percentage of the arithmetic
average value. Pepperl+Fuchs GmbH sensors
feature max. 10% ripple and comply with
standard EN 50008.
Rise time
The time it takes for an electric signal to
change from low to high.
Rotational speed
Specifies the mechanical load limit for the
rotary encoder. If this limit is exceeded it can
have a negative effect upon the service life of
the ball bearings. It can also result in signal
generation faults.
Rotational speed monitoring
The absolute rotary encoder monitors
the speed of the shaft. If the maximum
permissible speed of 6000 min-1 is exceeded,
the rotary encoder generates an alarm signal.
It is also possible to specify an application-
specific rotational speed trip value that is
monitored and reported upon in the case of
under or overshooting.
