AppendixC CommonQuestions
©NationalInstruments Corporation C-9 ATE Series User Manual
acquisitionc ompletes.The above error occurs because NI-DAQ disarms
the counter from generating any more requests in the interrupt service
routine. Due to interrupt latencies, it is possible that the counter may have
generated some spurious requests which the DMA controller may not
satisfybecause it has already transferred the required number of points.
Whata rethe PFIs and how do I configure these lines?
PFIsare Programmable Function Inputs. These lines serve as connections
to virtually all internal timing signals.
Ifyou areusi ngNI-DAQ or LabWindows/CVI, use the Select_Signal
functionto route internal signals to the I/O connector, route external signals
to internal timing sources, or tie internal timing signals together.
Ifyou are using NI-DAQ with LabVIEW and you want to connect external
signalsources to the PFI lines, y ou can use AI Clock Config,AI Trigger
Config,AO Clock Config, AO Trigger and Gate Config, and Counter Set
Attributeadvanced-level VIs to indicate which function the connected
signalserves. Use the Route Signal VI to enable the PFI lines to output
internal signals.
Caution Ifyou enable a PFI line for output, do not connect any external signal source to it;
if you do, you can damage the device,the c omputer,and the connected equipment.
TableC-1. Signal Name Equivalencies
HardwareSignal
Name LabVIEW RouteSignal NI-DAQ Select_Signal
TRIG1 AIStart TriggerND_IN_START_TRIGGER
TRIG2 AIStop TriggerND_IN_STOP_TRIGGER
STARTSCAN AIScan StartND_IN_SCAN_START
SISOURCE —ND_IN_SCAN_CLOCK_TIMEBASE
CONVERT* AIConvert ND_IN_CONVERT
AIGATE —ND_IN_EXTERNAL_GATE
WFTRIG AOStart Trigger ND_OUT_START_TRIGGER
UPDATE* AOUpdate ND_OUT_UPDATE
UISOURCE —ND_OUT_UPDATE_CLOCK_TIMEBASE
AOGATE —ND_OUT_EXTERNAL_GATE