Input- and Input+ contact points form the differential input of the strain gauge module, which receives the signal from sensor (strain gauge bridge).
Generator contact point is designed for supplying the power to sensor from a built-in generator of strain gauge module. The generator is controlled via Signal Generator software, and the signal is fed to all channels of strain gauge module.
Note: The generator also has a BNC output on the rear panel of strain gauge module.
Measurements are performed via Strain Gauge software. Each channel runs a separate instance of the software facility. You can run multiple instances for one measuring channel and adjust them for measurement of various parameters according to the relevant calibration tables. All settings are made in the Options window of Strain Gauge program. Additionally in the Device Manager program the signal conversion frequency for strain gauge module is set, specifying the names of measuring channels.
The signal at the strain gauge sensor output is proportional to the supplied power and applied load, so to obtain the measured values, it is necessary to carry out relative measurements, i.e. take into account the circuit power. To do this, the virtual channel of the generator or the input channel of strain gauge module can be used .
The Strain Gauge program not only displays the current measured value, but also creates a virtual channel available for display on a multi-channel oscillograph, signal parameter recorder, and in other ZETLAB TENZO software facilities.
Layouts of Resistive Strain Sensor Connection to Strain Gauge Module
The below figures show examples of resistive strain sensor connection to strain gauge module via four- and six-wire circuits.
Bridge connection circuit for resistive strain sensors (full bridge). One input channel is used for connection to strain gauge module (four-wire connection circuit). Measurements are relative to the virtual channel of the generator.
Bridge circuit, 4-wire connection to strain gauge module
Bridge connection circuit for resistive strain sensors (full bridge). Two input channels are used for connection to strain gauge module: measuring and reference. Measurements are relative to the reference channel.
Bridge circuit, 6-wire connection to strain gauge module
Connection of multiple strain gauge bridges to strain gauge module via one reference channel is used when distances between the measuring points are short.
Connection of multiple strain gauge bridges to strain gauge module via one reference channel
Connection of the half-bridge circuit to the strain gauge module requires resistive strain sensors with low temperature coefficient of resistance (TCR) for supplementing the circuit to complete the bridge.
R1 — temperature compensation; R2 — measuring; R3, R4 — constants with low TCR; R1≈R2≈R3≈R4