NI PXIe-6674T Calibration Procedure
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© National Instruments
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5
Measuring the Frequency
Complete the following procedure to measure the frequency of the onboard clock source.
1. Complete steps a to c to measure the oscillator frequency. To obtain an accurate
measurement for calibration, the measurement duration must be made sufficiently long.
Refer to Table 1 for the measurement duration to use.
a. Call niSync Initialize VI to set up a handle for the device.
b. Call niSync Measure Frequency VI to measure the frequency of the oscillator.
Table 1.
Measurement Duration
Device
Measure Accuracy
Required Measurement Duration
NI PXIe-6674T
0.5 ppb
20 seconds
LabVIEW Block Diagram
NI-SYNC C Function Call
Call
niSync_init
with the following
parameters:
resourceName
:
Dev1
idQuery
:
NULL
resetDevice
:
VI_FALSE
vi
:
*SessionHandle
LabVIEW Block Diagram
NI-SYNC C Function Call
Call
niSync_MeasureFrequency
with the following parameters:
vi
: “
<
SessionHandle
>
”
sourceTerminal
:
NISYNC_VAL_OSCILLATOR
duration
:
20
actualDuration
:
*actualDuration
measuredFrequency
:
*measuredFrequency
error
:
*error
