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EX1629 Basic Operation 49
COMPLETION RESISTOR/INPUT MULTIPLEXER DEFAULT SETTINGS
Table 3-2 contains the default input multiplexer and completion resistor values for each EU
conversion.
TABLE 3-2: DEFAULT COMPLETION RESISTOR/INPUT MULTIPLEXER VALUES
GAGE FACTOR / POISSON RATIO
As illustrated in the Engineering Unit (EU) Conversion subsection, there are two constants
utilized in the EU strain conversions: gage factor and Poisson ratio.
The gage factor (GF), a measure of strain gage sensitivity, is a dimensionless quantity defined as
the ratio of the fractional change in resistance to the fractional change in length along the primary
axis of the strain gage. Mathematically, this is expressed as:
The gage factor value for a specific strain gage is provided by the strain gage manufacturer. The
default gage factor is 2.0.
The Poisson ratio (ν), in simple terms, is a measure of the extent to which a material contracts as it
is being stretched. In engineering terms, it is a dimensionless quantity defined as the ratio of
transverse contraction strain to longitudinal extension strain in the direction of the stretching force.
Mathematically, this is expressed as:
The Poisson ratio value for a specific material should be obtained from a mechanical engineering
reference. The default Poisson ratio is 0.3.
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