The LabVIEW's Convert Strain Gauge Reading function in the scalar mode (available only at the RT target) allows you to perform the calculation on data acquired from the C modules.
To use the Convert Strain Gauge Reading function with voltage readings, you will need to change it to the scalar polymorphic type. To do this, you will need to right-click on Convert Strain Gauge Reading's icon>>Visible items>>Polymorphic VI selector>>Scalar. With the polymorphic VI now in the scalar mode you can wire up the required inputs and the VI will perfom the strain calculations and yield results in microstrain.
As seen in the LabVIEW examples there is a second way to perform this calculations (In this case the NI 9237 example will be reviewed).To find the module specific example of the NI 9237 go to Help>>Find Examples>>Compact RIO>>Module Specific>>NI 9237>>NI 9237 Getting Started.lvproj. In this project raw data is obtained by the FPGA module and then passed to the NI 9237 Getting Started (Host).vi by using a DMA FIFO. This VI performs the signal conditioning by first computing the offset measurment (offset nulling) and next performing a shunt calibration.Finally, already processed data is then transformed into strain measurments at the Ratio to Microstrain (SubVI).vi, notice that the applied formula conversion depends on the bridge configuration. For example, the Quarter Bridge Case I and II are calculated using math Vi's as shown in figure 2.
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