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Consider the General Notes on the Information in the Pepperl+Fuchs Product Catalogs
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Copyright Pepperl+Fuchs
Issue date:16.08.2012
Two-wire NAMUR photoelectric safety sen-
sors
These proximity switches are equivalent to
NAMUR sensors, although they behave in a
particular way: in the case of a system sen-
sor/control unit/extension cable malfunction,
the output of the control unit automatically
goes to the safe "OFF" state.
The model number for this type of sensor includes the ref-
erence -SN or S1N. They are supplied as:
•
NC contact (SN)
•
NO contact (S1N).
Sensors with relay contact output
Some sensors have relay contact outputs. The maximum
switching power and the type of voltage can be found in
the respective data sheets. The mechanical service life
data relates to the number of switching cycles for the un-
loaded relay contact output. This value is achieved with a
low electric contact load. Under nominal load for the con-
tacts, it reduces to the value specified for the electrical life.
The service life details are MTBF values.
Switching example:
U B
U B
1
2
3
4
5
6
A1
A2
A3
Three-wire
DC analog sensors
These sensors have separate connections for the power
supply and the output. An analog signal that is proportion-
al to the measured quantity can be tapped at the output.
The most widely used analog signals are 4 mA ... 20 mA
and 0 V ... 10 V.
Examples of the measured quantity include the object dis-
tance, an inclination angle, a filling level, a valve position,
or an acceleration value.
Most analog sensors have a parameterization option that
enables the output to be optimally adapted to the condi-
tions in the application.
Analog sensors often also have switching outputs for sig-
naling trip values (see Three-wire DC sensors).
Switching example:
1
+U B
5
2
4
-
U B
3
Lerneingang
Analogausgang
Synchronisation
S
The model number for this type of sensor includes the ref-
erence -I or -U. They are supplied as:
•
Current output, e.g., 4 mA ... 20 mA (I)
•
Voltage output, e.g., 0 V ... 10 V (U)
•
Current/voltage output with independent load
detection and function changeover (IU).
Three-wire DC sensors with frequency
output
These kinds of sensors (primarily ultrasonic sensors) in-
dicate the measured quantities within the detection area
in the form of a rectangular signal with variable frequency.
For example, when the fill level is S min the frequency out-
put supplies the lowest frequency value; when the fill level
is S max it supplies the highest frequency. The frequency
characteristic runs in a straight line between the measure-
ment range limits.
These sensors are also analog sensors with an output
signal that can be processed directly by the digital input
of a control unit.
Application example:
Sensor
Function of the output
Sensor
Frequency-
output
f max.
f min.
S min
S max
Switching example:
1
+U B
2
4
-
U B
3
XI
Ausgang
The model number for this type of sensor includes the ref-
erence -F.
Sensors and Systems
Introduction
