TESA-hite 400 / 700
3.4 Power supply
The TESA-Hite 400 / 700 is powered by a 6V rechargeable battery (N° 00760157). This is recharged
using the mains adapter N° 04761054 and the cable EU N° 04761055 or US N° 04761056
(see chapter 7.2 – Charging the battery).
3.5 Measuring system
The TESA-Hite 400 / 700 incorporates an opto-electronic measuring system which digitally records
the measured dimension, called the mesurande (TESA patent). A glass scale marked off in
incremental divisions serves as a material measure. According to the reflection principle, the glass
scale is scanned contactlessly by a sensor with photo-sensitive elements. After analogue/digital
conversion, the measurement signal is transmitted for processing. From point A, the reading system
can be moved downwards to the respective trigger points. Once one of these points has been
reached, the reading of the value is triggered, that is to say that the position of the measuring head in
relation to the incremental divisions is read off by the sensor. The distance C, symmetrical in relation
to the position of each trigger point in the travel of the measuring system is kept for seeking the
culminating point when probing cylindrical surfaces. (Read section 4.7 also).
<6 N
<6 N
~ 7 mm
1.5 N
C
~ 2 mm
C
~ 2 mm
~ 3 mm
0
~ 3 mm
~ 7 mm
A
1.5 N
D
D
B
B
A
Starting
position
B
Travel to upper or lower trigger point for taking reading
C
Partial measuring span for finding the culmination point
D
Travel in one direction from the neutral position to the spring-loaded end stop
3.6 Automatic measuring value correction
It is agreed that a perfectly accurate measuring instrument is impossible to produce. Therefore, the
value indicated by any instrument comprises a deviation from the true value; this deviation is
composed of the bias errors and the random errors. Random errors cannot be predicted since they
are the result of influences that cannot be controlled, e.g. the value dispersion. Bias errors, on the
other hand, as for example the deviations of the scale divisions on the material measure or the form
and positional errors of the measuring head guides can be corrected once they have been measured.
To correct length measurements, after the TESA-Hite 400 / 700 has been completely assembled; the
actual errors are determined step-by-step by means of a system of stepped gauge blocks.
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