Calibration With The Clamp-On Strain Transducer - HBM DD1 Montageanleitung

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10.4 Calibration with the clamp-on strain transducer

Relative strain e can then be determined in relation to the actual gage length
l *.
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e = n l / l *
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Example: The measured value for the change in length is + 2.67 V
+ 10 V = + 2 mm
+ 2.67 V = n l
n l = (+ 2.67 V x + 2 mm)/ +10 V
n l = 0.534 mm = 534 μm
The absolute change in length is 534 μm. The relative strain is derived from
the relation:
e = n l / l * = 534 μm / 0.050078 m = 10663 μm/m
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This conversion can be omitted if the measuring amplifier is calibrated to
provide a display with figures in the appropriate range. The measurement
signal is then directly proportional to the relative strain. For this purpose,
however, when calibrating with a calibration factor k you need to take the ratio
l */l into account when evaluating the output signal, by multiplying the end
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value of the calibration signal by k before you set it up.
Example:
Nominal length l
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strain of say 10000 μm/m is to be output with figures in the appropriate range.
At this strain the amplifier will be at full scale (Ua=10 V).
k = l * / l = 50.078 mm / 50 mm = 1.00156
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HBM
= 50 mm; actual gage length l * = 50.078 mm; a relative
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DD1
A0781-3.0 de/en