Multiple S series DAQ card

Question

Hi,
i will use multiple S series card (PCI 6143). I want to thread them as one card (by connecting them with RTS cables).
How can i program them?  I can't find any example about this
Thanx

Answer 1

Hi eesen-
I'm assuming that you'll most likely want to share a sample clock and/or AI start trigger between the two devices over RTSI.  In order to do this you will need to first export the appropriate signal from the 'master' device, like this:
theSTC->RTSI_Trig_A_Output.writeRTSI_Trig_2_Output​_Select(trigSelect);
// Set output select first, then route to RTSI to avoid glitching
theSTC->RTSI_Trig_Direction.writeRTSI_Trig_2_Pin_D​ir(1); // 0=input, 1=output
where RTSI_Trig_n refers to any of the RTSI trigger lines <0..6>.  Valid values for trigSelect are outlined on page 388 of the DAQ-STC Technical Reference manual.
On the 'slave' device you will then want to import the signals from RTSI.  For the ai/SampleClock, you'll need to make this change to the aiSampleStart() function (or just call this method with the appropriate setting):
theSTC->AI_START_STOP_Select.setAI_START_Select(tr​igSelect);
theSTC->AI_START_STOP_Select.setAI_START_Polarity(​tSTC::tAI_START_STOP_Select::kAI_START_PolarityRis​ing_Edge);
where AI_START refers to the ai/SampleClock signal that clocks each sample from the input ADC's.  Valid values for trigSelect are shown in the tSTC.h ChipObject file in the tAI_START_STOP_Select::tAI_START_Select enum.
For the ai/StartTrigger on the 'slave' device, you need to change this setting similarly as before (as shown from aiTrigger() in the DDK examples):
theSTC->AI_Trigger_Select.setAI_START1_Select(trig​Select);
theSTC->AI_Trigger_Select.setAI_START1_Polarity(tS​TC::tAI_Trigger_Select::kAI_START1_PolarityRising_​Edge);
Hopefully this helps-
Tom W
National Instruments