Section 8. Operation
434
negative excitations with the inputs reversed. The automatic procedure then is as
follows,
1. Switches to the measurement terminals
2. Sets the excitation, and then settle, and then
measure
3. Reverse the excitation, and then settles, and then
measure
4. Reverse the excitation, reverse the input terminals, settle,
measure
5. Reverse the excitation, settle,
measure
There are four delays per
measure
. The CR6 processes the four
sub-measurements into the reported measurement. In cases of excitation
reversal, excitation time for each polarity is exactly the same to ensure that ionic
sensors do not polarize with repetitive measurements.
Read More
A white paper entitled "The Benefits of Input Reversal and
Excitation Reversal for Voltage Measurements" is available at
www.campbellsci.com
.
Ground Reference Offset Voltage
When
MeasOff
is enabled (=
True
), the CR6 measures the offset voltage of the
ground reference prior to each
VoltSe()
or
TCSe()
measurement. This offset
voltage is subtracted from the subsequent measurement.
From Auto Self-Calibration
If
RevDiff
,
RevEx
, or
MeasOff
is disabled (=
False
), offset voltage compensation
is continues to be automatically performed, albeit less effectively, by using
measurements from the auto self-calibration. Disabling
RevDiff
,
RevEx
, or
MeasOff
speeds up measurement time; however, the increase in speed comes at
the cost of accuracy because of the following:
1
RevDiff
,
RevEx
, and
MeasOff
are more effective.
2 Auto self-calibrations are performed only periodically, so more time skew
occurs between the auto self-calibration offsets and the measurements to
which they are applied.
Note
When measurement duration must be minimal to maximize
measurement frequency, consider disabling
RevDiff
,
RevEx,
and
MeasOff
when CR6 module temperatures and return currents are slow to
change.
Summary of Contents for CR6 Series
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Page 76: ...Section 5 Overview 76 FIGURE 20 Half Bridge Wiring Example Wind Vane Potentiometer ...
Page 80: ...Section 5 Overview 80 FIGURE 23 Pulse Input Wiring Example Anemometer ...
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Page 454: ...Section 8 Operation 454 FIGURE 104 Narrow Sweep High Noise ...
Page 459: ...Section 8 Operation 459 FIGURE 106 Vibrating Wire Sensor Calibration Report ...
Page 535: ...Section 8 Operation 535 8 11 2 Data Display FIGURE 121 CR1000KD Displaying Data ...
Page 537: ...Section 8 Operation 537 FIGURE 123 CR1000KD Real Time Custom ...
Page 538: ...Section 8 Operation 538 8 11 2 3 Final Storage Data FIGURE 124 CR1000KD Final Storage Data ...
Page 539: ...Section 8 Operation 539 8 11 3 Run Stop Program FIGURE 125 CR1000KD Run Stop Program ...
Page 541: ...Section 8 Operation 541 FIGURE 127 CR1000KD File Edit ...
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Page 610: ...Section 11 Glossary 610 FIGURE 137 Relationships of Accuracy Precision and Resolution ...
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