Campbell CR3000 Micrologger, Operator'S Manual

Page: 378 / 644

Section 8. Operation
378
Calibrate() Instruction Results
Cal()
Array
Field
Descriptions of Array Elements
Typical Value
Differential (Diff)
Single-Ended (SE) Offset or Gain
±mV Input
Range Integration
31 SE Offset 5000 50-Hz Rejection ±25 LSB
32 Diff Offset 5000 50-Hz Rejection ±25 LSB
33 Gain 5000 50-Hz Rejection –0.167 mV/LSB
34 SE Offset 1000 50-Hz Rejection ±25 LSB
35 Diff Offset 1000 50-Hz Rejection ±25 LSB
36 Gain 1000 50-Hz Rejection –0.0333 mV/LSB
37 SE Offset 200 50-Hz Rejection ±30 LSB
38 Diff Offset 200 50-Hz Rejection ±30 LSB
39 Gain 200 50-Hz Rejection –0.00667 mV/LSB
40 SE Offset 50 50-Hz Rejection ±30 LSB
41 Diff Offset 50 50-Hz Rejection ±30 LSB
42 Gain 50 50-Hz Rejection –0.00167 mV/LSB
43 SE Offset 20 50-Hz Rejection ±35 LSB
44 Diff Offset 20 50-Hz Rejection ±35 LSB
45 Gain 20 50-Hz Rejection –0.00067 mV/LSB
8.1.2.5 Strain Measurements — Details
Related Topics:
• Strain Measurements — Overview
(p. 74)
• Strain Measurements — Details
(p. 378)
• FieldCalStrain() Examples
(p. 243)
A principal use of the four-wire full bridge is the measurement of strain gages in
structural stress analysis. StrainCalc() calculates microstrain (
µ ε) from the
formula for the particular strain bridge configuration used. All strain gages
supported by StrainCalc() use the full-bridge schematic. In strain-gage parlance,
'quarter-bridge', 'half-bridge' and 'full-bridge' refer to the number of active
elements in the full-bridge schematic. In other words, a quarter-bridge strain
gage has one active element, a half-bridge has two, and a full-bridge has four.
StrainCalc() requires a bridge-configuration code. The table StrainCalc()
Instruction Equations
(p. 379)
shows the equation used by each configuration code.
Each code can be preceded by a dash (-). Use a code without the dash when the
bridge is configured so the output decreases with increasing strain. Use a dashed
code when the bridge is configured so the output increases with increasing strain.
A dashed code sets the polarity of V
r
to negative.