AppendixC CommonQuestions
©NationalInstruments Corporation C-5 ATE Series User Manual
4. InitiateAO waveform generation.
If you are using NI-DAQ,call WFM_Group_Control with operation
setto 1 (start).
Ifyou are using LabVIEW, you can invokeAO Control VI with control
code set to0 (start).
Can I programmaticallyenable different channels on an E Series
boardt o acquirein different modes? For example, Channel 0 is
differentialand Channel 1 is RSE.
Differentchannels on an E Series device can be enabled to acquire in
differentmodes. However, different pairs of channels are used in different
modes.In the example configuration given above, ACH0 and ACH8would
be configuredin differential mode and ACH1 and AIGND would be
configuredin RSE mode. In this configuration, ACH8 could not be used in
asingle-ended configuration. To enable multi-mode scanning in LabVIEW,
youwould use t he coupling& input config cluster input of the AI Config
VI.This input has a 1-to-1 correspondence with the channels array input of
theAI ConfigVI. Therefore, you m ust list all channels either individually
orin groups of channels with the s ame input configuration. Forexample, if
you wantChan nel 0 to be differentialand Channels 1 and 2 to be RSE.
Figure C-1 demonstrates howto program this configuration in LabVIEW.
FigureC-1. Configuring Channels for Different Acquisition Modes in LabVIEW
Iam seeing crosstalk or ghost voltages when sampling multiple
channels.What does this mean?
Youmaybe experiencing a phenomenon called charge injection, which
occursw henyou are sampling a series of high output impedance sources
with a multiplexer.Multiplexers contain switches, usually made of
switched capacitors. When one of the channels, for example channel 0, is
selected in a multiplexer,those capacitors accumulate charge. When the
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