Analog Channels - HBM SomatXR CX23-R User Manual

4 Setting up and running a test
44
mode is selected. Calculation of the equivalent strain sets the Physical span value.
(Page 44) for detailed information.
Define known shunt
The define know shunt option calculates the equivalent Physical span from a known
shunt.
Enter the known shunt resistance and equivalent physical value and click OK.
This shunt tool allows the user to define a calibration step consisting of the selection
of any one of the FCS shunt resistors along with the corresponding equivalent
engineering value based on another Known Shunt calibration (an example of a
Known Shunt calibration is that a 33.2 KOhm shunt produces a 2200 lb output). The
equivalent engineering values for the FCS shunt resistors are computed using the
following formula:
V = V * ((R + 2 * R
e k g
V = equivalent engineering units value
e
V = known engineering units value
k
R = nominal gage resistance
g
R = known shunt resistance
sk
R = equivalent shunt resistance
se
Equivalent strain calculator
This shunt tool is only applicable when the shunt scaling mode is selected.
Calculation of the equivalent strain sets the Physical span value.
The equivalent strain value is calculated from the bridge resistance, shunt
resistance, shunt polarity, strain gage factor and bridge factor. When any of these
values are changed, the equivalent strain value and Physical span are no longer valid
and must be recalculated.
Following is the formula for computing this in μm/m (microstrain) units if the shunt
polarity is Up scale. If the shunt polarity is Down scale, multiply by -1.0.
ES = 4.0e+06 * (R
b
R = Bridge resistance
b
R = Shunt resistance
s
GF = Strain gage factor (default is 2.0)
BF = Bridge factor (default is 1.0)
ES = Equivalent strain
4.3.3 Analog channels
Analog channels include
Piezoresistive transducers,
fed piezoelectric transducers (IEPE,
measurements.
a4275-8.0 en HBM: public
) / (R + 2 * R )) , where:
sk g se
/(2 * R + 4 * R )) / (GF * BF) , where:
b s
Strain gage transducers,
Potentiometric
ICP®),
Inductive transducers,
transducers, Voltage sources,
Current sources and Resistance-based
CX23-R and EX23-R
Current-