Functional Principle, Technical Data - MICRO-EPSILON induSENSOR DTA-1G8 Betriebsanleitung

Functional Principle, Technical Data

2.
Inductive gauges of the LVDT series are passive components without integral electronics.
Consequently, suitable signal conditioning electronics are needed for operation (e.g. controller MSC7401,
MSC7802, MSC7602). The technical data are only valid, if the values specified for excitation (excitation fre-
quency and excitation voltage) are complied with.
Inductive gauges work according to the LVDT principle (Linear Variable Differential Transformer; full bridge)
and consist of a primary and two secondary coils with a common moveable soft-magnetic core.
Secondary +
Secondary -
Secondary
center tap
Primary -
Primary +
Sensor cable
shield
Fig. 1 Gauge based on the LVDT principle
An oscillator electronics excites the primary coil with an alternating current of constant frequency.
Depending on the core position, alternating voltages are induced in both secondary coils, in relation to the
core position. Displacement of the core causes a higher voltage in one secondary coil and a lower voltage in
the second coil. The difference between both secondary voltages is proportional to the core displacement.
At the mechanical zero point, the signal in the two secondary coils is cancelled out due to the position of the
probe tip. The gauge provides the signal 0 volt. The mechanical zero point is the center point of the linear
measuring range (± measuring range). The range of the probe tip movement is considerably larger than the
linear measuring range, and it depends on the gauge.
induSENSOR, Series LVDT, Gauge
Functional Principle, Technical Data
Soft-magnetic core Plunger
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