TESA-hite 400 / 700
4.5 Establishing the probe constant for length measurements with inversion of the
probing direction
When bores, shafts, grooves, etc. are measured with a change of probe direction, a gauge-head
constant must be taken into account. In order that the user may effect all these measurements
without having to resort to tire some calculations, the gauge-head constant is determined on a
suitable master gauge whose actual dimension is known. Setting piece No. 00760219 is provided
with the instrument. By combining the three gauge blocks of which it consists, it has a total internal
or external dimension of 6,350 mm / .25000 in.
Remark
• Use only the setting piece supplied with the
TESA-Hite 400 / 700 bearing with the N° 00760219
and the same production number as the instrument.
• The final TESA-Hite 400 / 700 verification and the
certificate supplied both refer to this reference
gauge.
The gauge-head constant, which is a permanent correction factor, is calculated by the built-in
program once the measurements on the master-gauge have been completed; it is then recorded and
automatically taken into account for all subsequent measurements.
By applying a gauge-head constant, the following features – which can affect the measurements –
will be considered or compensated:
• Diameter of the probe ball or disc used.
• Elastic distortion of the probe and its support under the action of the measuring force.
• Hysteresis errors of the measuring system.
The gauge-head constant must be redetermined after any change in the measuring conditions.
Main causes of change:
• Turning the instrument off.
• Changing the probe.
• Changing the probe position.
The «Determination a gauge-head constant» function requires at least two probe contacts at each
measuring point. The difference between the two readings at each measuring point should not exceed
1 µm. Should the instrument indicate a greater difference, it will be displayed and the operator must
either accept that difference or repeat the gauge-head constant determination operation.
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