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2.1 Instructions for use of strain gauge Sensors
Notice:
Strain gauge sensors with a small range are extremely sensitive to improper handling. Force
transducers can be destroyed simply by touching. Same applies for the diaphragms of pressure
transducers. So bear in mind: handle with care!
Loading the transducer in excess of the nominal range may result in an increased and lasting zero
balance offset as well as damage to the sensor. The same applies to short-term force or pressure
impulses that exceed the nominal range.
To most force transducers the force must be applied centrically in order to avoid shear forces, which
may be harmful to the sensor, or may cause measurement inaccuracy. Centric force transmission can
be ensured by rounded surfaces, joint heads or other suitable guides.
Tightening torques while mounting any sensor may result in an increased zero balance offset.
If the sensor has been replaced, the calibration of the amplifier must be checked. A new adjustment
might be necessary.
3 Technical Description
The described 2 channel measuring amplifier serves to supply one or two strain gauge sensors with a
full bridge resistance of 300 ohms or more and the amplification of the sensor signal.
The supply voltage of the amplifier is galvanically isolated from analogue output, sensor supply and
sensor signal.
The circuitry is in 4-wire technology. Standard analogue outputs are available for further evaluation.
The amplifier is built in a robust aluminum die cast housing, which is suited for rough and industrial
environment.
The coarse amplification is determined by an internal resistor and can be fine adjusted by a
potentiometer After opening the lid the potentiometer mentioned before as well as the potentiometer
for zero-adjustment allow a correction of the calibration. In addition, a dip-switch allows to change
the width of the zero adjustment range. If even this expansion of the range should not be sufficient,
an internal resistor can be soldered in to add a tare.
