Section 8. Operation
401
Note When measurement duration must be minimal to maximize
measurement frequency, consider disabling RevDiff, RevEx, and
MeasOff when CR3000 module temperatures and return currents are slow
to change.
Time Skew Between Measurements
Time skew between consecutive voltage measurements is a function of settling
and integration times, A-to-D conversion, and the number entered into the Reps
parameter of the VoltDiff() or VoltSE() instruction. A close approximation is:
time skew = settling
time + integration time + A-to-D conversion time + reps
where A-to-D conversion time equals
125
µs. If reps (repetitions) > 1 (multiple
measurements by a single instruction), no additional time is required. If reps = 1
in consecutive voltage instructions, add 15 µs per instruction.
Measurement Accuracy
Read More For an in-depth treatment of accuracy estimates, see the
technical paper Measurement Error Analysis soon available at
www.campbellsci.com/app-notes.
Accuracy describes the difference between a measurement and the true value.
Many factors affect accuracy. This section discusses the affect percent-or-
reading, offset, and resolution have on the accuracy of the measurement of an
analog voltage sensor signal. Accuracy is defined as follows:
accurac
y = percent
-of-r offset
where percents-of-reading are tabulated in the table Analog Voltage Measurement
Accuracy
(p. 352),
and offsets are tabulated in the table Analog Voltage
Measurement Offsets
(p. 352).
Note Error discussed in this section and error-related specifications of
the CR3000 do not include error introduced by the sensor or by the
transmission of the sensor signal to the CR3000.
Analog Voltage Measurement Accuracy
1
0 to 40 °C
–25 to 50 °C
–55 to 85 °C
2
±(0.04% of r
offset)
±(0.07% of r
offset)
±(0.09% of r
offset)
1
Assumes the CR3000 is within factory specifications
2
Available only with purchased extended temperature option (-XT)
Summary of Contents for CR3000 Micrologger
Page 2: ......
Page 3: ......
Page 4: ......
Page 6: ......
Page 30: ......
Page 34: ......
Page 36: ......
Page 96: ......
Page 485: ...Section 8 Operation 485 8 11 2 Data Display FIGURE 110 Keyboard and Display Displaying Data ...
Page 487: ...Section 8 Operation 487 FIGURE 112 CR1000KD Real Time Custom ...
Page 491: ...Section 8 Operation 491 FIGURE 116 Keyboard and Display File Edit ...
Page 496: ......
Page 502: ......
Page 564: ...Section 11 Glossary 564 FIGURE 126 Relationships of Accuracy Precision and Resolution ...
Page 566: ......
Page 594: ......
Page 598: ......
Page 600: ......
Page 602: ......
Page 624: ......
Page 642: ......
Page 643: ......