Sample Rate Adjustments Do Not Affect LC Measurements of a DMM Hardware: Modular Instruments>>Digital Multimeters (DMM)>>PXI-4072
Problem: I have tried adjusting the sample rate of an inductance or capacitance (LC) measurement using the NI-DMM driver. However, the changes have no effect on my actual measurement speed. Solution: This is expected behavior. The reading rate is solely dependent on the range of your measurement. Different ranges use different frequencies of test signals, thereby requiring different measurement times. These ranges are described in the NI Digital Multimeters Help. The aperture time is fixed and cannot be changed with a property node call. While it may appear that the aperture time is changing by adjusting the measurement resolution using NI-DMM property nodes, it will not make a difference to the actual sample rate of your measurement. The DMM uses the default minimal settling time (3 μs) during the measurement cycle. AutoZero and ADC Calibration are also not available for LC measurements, so adjusting these parameters will not affect your reading rate. To achieve maximum measurement speed, use a multipoint acquisition rather than single point measurements because switching and settling times are kept to a minimum. Related Links: Attachments:
Report Date: 10/05/2007 Last Updated: 10/15/2007 Document ID: 4E406AGW |
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