Network Card User Manual

Appendix C Common Questions

acquisition completes. 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

satisfy because it has already transferred the required number of points.

What are the PFIs and how do I configure these lines?

PFIs are Programmable Function Inputs. These lines serve as connections

to virtually all internal timing signals.

If you are using NI-DAQ or LabWindows/CVI, use the

Select_Signal

function to route internal signals to the I/O connector, route external signals

to internal timing sources, or tie internal timing signals together.

If you are using NI-DAQ with LabVIEW and you want to connect external

signal sources to the PFI lines, you can use AI Clock Config, AI Trigger

Config, AO Clock Config, AO Trigger and Gate Config, and Counter Set

Attribute advanced-level VIs to indicate which function the connected

signal serves. Use the Route Signal VI to enable the PFI lines to output

internal signals.

Caution

If you enable a PFI line for output, do not connect any external signal source to it;

if you do, you can damage the device, the computer, and the connected equipment.

Table C-1.

Signal Name Equivalencies

Hardware Signal

Name

LabVIEW Route Signal NI-DAQ Select_Signal

TRIG1 AI Start Trigger ND_IN_START_TRIGGER

TRIG2 AI Stop Trigger ND_IN_STOP_TRIGGER

STARTSCAN AI Scan Start ND_IN_SCAN_START

SISOURCE — ND_IN_SCAN_CLOCK_TIMEBASE

CONVERT* AI Convert ND_IN_CONVERT

AIGATE — ND_IN_EXTERNAL_GATE

WFTRIG AO Start Trigger ND_OUT_START_TRIGGER

UPDATE* AO Update ND_OUT_UPDATE

UISOURCE — ND_OUT_UPDATE_CLOCK_TIMEBASE

AOGATE — ND_OUT_EXTERNAL_GATE