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National Instruments Corporation
15
NI PXI-4070 Calibration Procedure
29. Set the input resistance of the NI 4070 to 10 M
Ω
by calling
niDMM_SetAttributeViReal64
with the following parameters:
•
Attribute_ID
=
NIDMM_ATTR_INPUT_RESISTANCE
•
Attribute_Value
=
NIDMM_VAL_10_MEGAOHM
30. Call
niDMM_ConfigureMultiPoint
with the following parameters:
•
Trigger Count
=
1
•
Sample Count
=
10
•
Sample Trigger
=
NIDMM_VAL_IMMEDIATE
•
SampleInterval
=
–1
31. Call
niDMM_ReadMultiPoint
with the following parameters:
•
Maximum Time
=
NIDMM_VAL_TIME_LIMIT_AUTO
•
Array Size
=
10
Average the results by summing the returned reading array of the
function and dividing by the returned actual number of points. Store
the result as the 100 mV 10 M
Ω
mode offset.
32. Output 100 mV on the calibrator with the range locked to 2.2 V. This
range prevents a 50
Ω
calibrator output resistance from creating a
voltage divider with the internal resistance of the NI 4070.
33. Call
niDMM_ConfigureMeasurement
with the following
parameters:
•
Function
=
NIDMM_VAL_DC_VOLTS
•
Range
=
0.1
•
Resolution
=
100e–9
34. Set the input resistance of the NI 4070 to >10 G
Ω
by calling
niDMM_SetAttributeViReal64
with the following parameters:
•
Attribute_ID
=
NIDMM_ATTR_INPUT_RESISTANCE
•
Attribute_Value
=
NIDMM_VAL_GREATER_THAN_10_GIGAOHM
35. Call
niDMM_Read
. Subtract the previously stored 100 mV >10 G
Ω
mode offset from this measurement and verify that the result falls
between the limits listed in Table 11.
36. Set the input resistance of the NI 4070 to 10 M
Ω
by calling
niDMM_SetAttributeViReal64
with the following parameters:
•
Attribute_ID
=
NIDMM_ATTR_INPUT_RESISTANCE
•
Attribute_Value
=
NIDMM_VAL_10_MEGAOHM
37. Call
niDMM_Read
. Subtract the previously stored 100 mV >10 M
Ω
mode offset from this measurement and verify that the result falls
between the limits listed in Table 11.
