Another advantage of the shunt load is its very high resistance to overload ability. If you need to measure the size of the absolute force, installed on the power distribution of sensor calibration must be carried out after installation. Because of the sensitivity is through the force measurement and force distribution is itself dependent on point, calibration are only effective when at a fixed force distribution state. So for application of fixed, such as monitoring of power installation, force shunt measurement when the preferred measurement method.
Sensors installation and power point not only affects the sensitivity of the sensor, but also affect its linear and hysteresis.
Force distribution n (%) = 100. Fn/Fp
N = force shunt (not the sensor measuring the process of force ratio); Fp = process force; N = 0 (no preloading, before the installation of sensors); So = before installation of the sensor sensitivity; S = after installation of sensors; Fn = shunt. S = So, (1 - n / 100)
Advantages: strong overload capacity resistance, low cost, measurement process of force than the sensor measuring range can be up to 100 / (100 - n) times, reliable at steady state accuracy and high repeatability.
Weakness: the measured values associated with power point and force transfer path, measuring absolute force, need calibration.
The indirect load
When on a structure force f, caused by structure deformation can be proportional to the force of the strain is measured. Thus indirect force can through the surface or structure strain during measurement. Stone edge is proportional to the strain sensor converts the strain force, and generate corresponding electrical signals. Therefore often referred to as the force and strain sensor.
Sensitivity of strain by the unit mu epsilon (mu m/m) corresponding charge to determine, without calibration commonly, because of the strain is very small, negligible. When used to measure the absolute value, the strain sensitivity of the measurement chain (v/kN), usually as a reference to relative force sensor calibration. But for the cycle process, usually monitoring force curve relative change is enough, do not need to determine the absolute value.
Advantages: installation way the most simple, match, existing equipment simple, strong resistance to overload ability, economic cost.
Weakness: the measured values associated with power point and force transfer path, measure the absolute value require field calibration.
4) piezoelectric measuring chain
Most of the calibrate piezoelectric sensors in before they leave the factory, so can be used to directly measure immediately. With the same sensitivity of several sensors can also be used in parallel. In this case, the output signal is equal to the sum of all inpidual force. These sensors with high insulation special cable connected to the charge amplifier. Charge amplifier converts the sensor signal is proportional to the charge voltage signal. Charge amplifier can be set on the sensor's sensitivity and the measuring range. This chain of calibration of measuring output signal can be showed and post-processing.
Measurement and analysis
Signal conditioning for measuring torque force, strain and physical properties are very important. Piezoelectric sensors and sensor are load linearly proportional to electrical signals. Need charge amplifier will charge signal is converted to a voltage or current signal, then signal processing. Stone edge in order to meet different requirements in the practical application, offers a variety of charge amplifier, their structure, channel number, precision, measurement range, sensitivity, bandwidth and output filtering properties, scale and evaluation of signal aspects are different.
Today's commonly used computer record the measurement data. To the function of display and software evaluation force signal and high requirement of friendly user interface, etc. Stone edge DasView data analysis software is particularly suited to match dynamometer or single, multi-way force sensor is used. Analysis in signal analysis, DasView can show online signal waveform, with functions of statistical analysis and charts. In addition to the software acquisition instrument for measuring chain set, also supports a single measurement data files are generated, and the establishment of database configuration, and measurement results and the management. 压电式力和力矩传感器英文文献和中文翻译(5):http://www.youerw.com/fanyi/lunwen_9938.html