The strain gauge (SG) simulators models 9405 allow rapid and easy calibration of measuring chains consisting of, for example, a load sensor, a connecting lead and indicator.
All measuring amplifiers and displays suitable for SG sensors can be connected, checked and calibrated. The supply voltage source is loaded realistically by the simulator. Deviations from the rated supply voltage as well as the influence of the connection leads are taken into account during calibration. Particularly in the case of long leads, this has a decisive influence on the accuracy which can be achieved with the entire measuring chain.
Because of the reversible polarity the SG simulator allows the examination of measuring chains, for tension and compression measurement or differential pressure.
The most accurate method of calibrating a measuring chain is the comparison with a high-precision reference. This also applies to SG sensors. A mechanical variable, whose value is exactly known, loads the sensor. It yields, via a detuning in the bridge circuit, to a corresponding output signal. By these means, the measuring chain can be adjusted. This method is often unfeasible (for example, due to very large measuring ranges of several hundred tons or several hundred bars) or too complicated. In such cases, the measurement variable must be simulated electrically. This can be done very easy and with high precision using a simulator model 9405. Instead of the sensor, the simulator is connected to the measuring chain. It loads and thus tests the supply voltage source, and simulates the zero signal and the signal for a load, corresponding to the sensitivity of the sensor. As in the case of the SG sensor, this is achieved by a change in resistance.
Measuring chains with sensors, whose actual (not rated) sensitivity is slightly different than the simulator´s signal, can also be adjusted by means of a simple ratio calculation.
The internal circuit is not in accordance with a Wheatstone bridge. This is the reason why shunt calibration is not possible. But in most cases it is not required.