Setting the optimal bridge supply voltage for sensors with strain gauges
Depends on:
On the one hand, a higher output signal is obtained at a strain gauge bridge circuit with a higher bridge feed tension, and thus a smaller gain needed. This reduces the noise amplitude, because the noise amplitude is mainly responsible for the analog amplifier in front of an A / D converter.
On the other hand, the bridge supply voltage ensures self-heating of the strain gauge measuring lattice. A too high supply voltage generally ensures different and unstable temperatures on the measuring grinders, which can lead to strong switch-on drift, but also to constant, low-frequency variations in the output signal.
Also, the resistance of the individual strain measuring strips has an influence on self-heating. Advantageously with the most widely used strain gauge 350 ohms are therefore 5V at 3 mm lattice length, but also 2.5V at 350 ohms and 1.5mm or 1 mm lattice length (thumbnail sensors). Also, the measuring range of the sensor can have an influence on the optimally set supply voltage. Sensors with small measuring ranges, such as 2n or 1n offer little "heatsink" for the strain gauge.
For the measuring amplifiers GSV-2 and GSV-8, the bridge supply voltage can be adjusted, and thus the measuring range changes. The reinforcement remains unchanged in this measuring amplifier.
A low bridge supply voltage is usually a sign of high-quality analog components.