Campbell CR800 Series, Руководство оператора

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Section 8. Operation
343
Calibrate() Instruction Results
Cal()
Array
Field
Descriptions of Array Elements
Typical Value
Differential (Diff)
Single-Ended (SE)
Offset or Gain
±mV Input
Range
Integration
52 SE Offset 2.5 50 Hz Rejection ±20 LSB
53 Diff Offset 2.5 50 Hz Rejection ±20 LSB
54 Gain 2.5 50 Hz Rejection –0.00067 mV/LSB
8.1.2.5 Strain Measurements — Details
Related Topics:
• Strain Measurements — Overview
(p. 70)
• Strain Measurements — Details
(p. 343)
•
FieldCalStrain() Examples
(p. 228)
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. 343)
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.
StrainCalc() Instruction Equations
StrainCalc()
BrConfig
Code Configuration
1
Quarter-bridge strain gage
1
:
2
Half-bridge strain gage
1
. One gage parallel to strain, the
other at 90° to strain: