Measurement Circle; Frequency And Acceleration Limits - HBM WI/5mm-T Montageanleitung

WI

5.4 Measurement circle

The measurement circle means the sum of all the dimensions included in the
displacement measurement, that is, the dimensions of the
• transducer
• core or probe pin
• workpiece
• workpiece fastener
• transducer fastener
Temperature changes shift the zero signal of the inductive measurement
system by a small amount. Also the nominal output span of the transducer
changes with temperature (for max. temperature variations see chapter 9).
In most cases a temperature change results in the thermal expansion of
different materials in the measurement configuration itself. When high levels
of precision are required it is essential to take account of every thermal
expansion in the measurement circle. The specifications apply to clamping
with the aid of steel parts with a thermal expansion of 11 x 10

5.5 Frequency and acceleration limits

The measurement frequency range of the measurement chain has to be
determined electrically from the upper cut off frequency of the amplifier. You
can find the appropriate data in the operating manual for your amplifier.
Maximum permissible acceleration has a decisive effect on the mechanical
characteristics of the displacement transducer (see Specifications, page 37).
In the case of displacement probes, care must be taken that the probe pin
does not withdraw from the measurement object due to inertia.
To a first approximation, many tasks may generally be regarded as sinusoidal.
At maximum permitted acceleration a
the mechanical cut off frequency f
= 1 /(2 π)
f
max
A1028 3.1 de/en/fr
with given displacement amplitude s
max
is:
max
(a / s)
max
31
/ °C.
−6
HBM