Section 8. Operation
399
effect is caused by dielectric absorption of the integrator capacitor and cannot be
overcome by circuit design. Remedies include the following:
•
Program longer settling times
•
Use an individual instruction for each input terminal, the effect of which
is to reset the integrator circuit prior to filtering.
•
Avoid preceding a very small voltage input with a very large voltage
input in a measurement sequence if a single measurement instruction
must be used.
TABLE: Offset Voltage Compensation Options
(p. 349)
lists some of the tools
available to minimize the effects of offset voltages.
Offset Voltage Compensation Options
CRBasic
Measurement
Instruction
Input Reversal
(RevDiff =True)
Excitation
Reversal
(RevEx = True)
Measure
Offset During
Measurement
(MeasOff = True)
Measure Offset
During
Background
Calibration
(RevDiff = False)
(RevEx = False)
(MeasOff = False)
AM25T()
BrHalf()
BrHalf3W()
BrHalf4W()
BrFull()
BrFull6W()
Resistance()
TCDiff()
TCSe()
Therm107()
Therm108()
Therm109()
VoltDiff()
VoltSe()
Input and Excitation Reversal
Reversing inputs (differential measurements) or reversing polarity of excitation
voltage (bridge measurements) cancels stray voltage offsets. For example, if 3
µ
V offset exists in the measurement circuitry, a 5 mV signal is measured as 5.003
mV. When the input or excitation is reversed, the second sub-measurement is –
Summary of Contents for CR3000 Micrologger
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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 ...
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