Chapter 2 Function Reference — Select_Signal
NI-DAQ FRM for PC Compatibles 2-386
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National Instruments Corporation
Example
status = Select_Signal (1, ND_START_TRIGGER, ND_RTSI_5, ND_LOW_TO_HIGH);
This example would route RTSI lines to be the start trigger for th e counters on th e TIO board.
When RTSI lines have a rising edge, all counters configured for hardware triggering will
begin counting. The software start must be issued to the counter before the hardware trigger
will work.
Using This Function
If you have selected a signal that is not an I/O connector pin, pin or a RTSI bus line,
Select_Signal saves the parameters in the configuration tables for future operations.
Functions that which initiate data acquisition (DAQ_Start, SCAN_Start, DAQ_Op, and
SCAN_Op) and waveform generation operations (WFM_Group_Control and WFM_Op) use the
configuration tables to set the device circuitry to the correct timing modes.
You do not need to call this function if you are satisfied with the default settings for the
signals.
If you have selected a signal that is an I/O connector, connector or a RTSI bus signal,
Select_Signal performs signal routing and enables or disables output on a pin.pin or a
RTSI line.
Example: Sending a signal from your ESeries device to the RTSI bus
To send a signal from your ESeries device to the RTSI bus, set signal to the appropriate RTSI
bus line and source to indicate the signal from your device. If you want to send the analog
input start trigger on to RTSI line 3, use the following call:
Select_Signal(deviceNum, ND_RTSI_3, ND_IN_STAR T_ TR IGG ER , ND _LO W_ TO _HI GH )
Example: Receiving a signal from the RTSI bus on your ESeries device
To receive a signal from the RTSI b us and use it as a signal on your ESeries device, set signal
to indicate the appropriate ESeries device signal and source to the appropriate RTSI line. If
you want to use low-to-high transitions of the signal present on the RTSI line 4 as your scan
clock, use the following call:
Select_Signal(deviceNum, ND_IN_SCAN_START, ND_ RT SI _4, N D_ LO W_T O_ HI GH)
ND_PFI_0 through ND_PFI_39 ND_LOW_TO_HIGH or
ND_HIGH_TO_LOW
ND_RTSI_0 through ND_RTSI_6 and ND_RTSI_CLOCK ND_LOW_TO_HIGH or
ND_HIGH_TO_LOW
source sourceSpec