turck Li-Q25LxE Series - Properties and Features; Operating Principle; Functions and Operating Modes; Output Function

9
2018/10
4.2 Properties and features
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Measuring lengths of 100…2000mm
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Shock-proof up to 200 g
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Keeps linearity under shock stress
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Magnetic field immunity
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5kHz scan rate
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16-bit resolution
4.3 Operating principle
The Li-Q25L linear position sensors have contactless operation based on the inductive resonant
circuit measuring principle. Measuring is insensitive to magnetic fields as the positioning ele-
ment is not based on a magnet but on a coil system.
Sensor and positioning element form an inductive measuring system. An induced voltage gen-
erates appropriate signals in the receiver coils of the sensor, depending on the position of the
positioning element. The signals are evaluated in the internal 16-bit processor of the sensor and
output as analog signals.
4.4 Functions and operating modes
The devices are provided with a current and voltage output. The device output provides a cur-
rent and voltage signal that is proportional to the position of the positioning element.
Fig. 2: Output characteristics – Device with 0…10V voltage output
and 4…20mA current output
4.4.1 Output function
The measuring range of the sensor starts at 4mA or 0V and ends at 20mA or 10V.
Current and voltage outputs can be used simultaneously. The simultaneous use of current and
voltage output can be used for redundant signal evaluation. A display device can also receive a
signal while the second signal is further processed by a PLC.
Besides the LEDs the sensor provides an additional control function. If the positioning element
is outside of the detection range and the coupling between the sensor and the positioning
element is thus broken, the analog output of the sensor is 24mA or 11V. This error can thus be
evaluated directly via the higher-level controller.
A
I [mA]U [V]
0
B
AB
4
10
11
20
24