Analog out triggered by PFI? (DAQmx C)

[elleryjh]

I'm trying to trigger a change in an analog output signal based on a digital input.

1. AO = 1V
2. DI Trigger rises
3. Prepare AO for 2V
4. DI Trigger falls=>AO goes to 2V

I have the digital trigger going into PFI1, which seems to work to trigger a continuous sine wave in MAX, but I'm unable to do it with the DAQmx C SDK.

I think it's a combination of DAQmxCfgSampClkTiming and/or DAQmxCfgDigEdgeStartTrig, but I'm unable to get it working.

Here's my code, simplified:

void setup(){
   DAQmxCreateAOVoltageChan(handle,"Dev0/ao1","",-10.0,10.0,DAQmx_Val_Volts,"");
   DAQmxCfgDigEdgeStartTrig (handle, "Dev0/PFI1", DAQmx_Val_Falling);
}

void changeVoltage(float v){
   DAQmxWriteAnalogScalarF64(handle,true,100.0,Voltage,NULL);
}

The call to DAQmxWriteAnalogScalarF64 produces error -200262: An attempt has been made to configure a trigger without configuring the appropriate sample clock properties or when Sample Timing Type was set to On Demand.

So I added:

DAQmxCfgSampClkTiming(handle, NULL, 500000, DAQmx_Val_Falling, DAQmx_Val_HWTimedSinglePoint, 1);

but now DAQmxWriteAnalogScalarF64 produces error -89120: Source terminal to be routed could not be found on the device.

So what am I missing here?  Thanks for any and all help!

DAQmxWriteAnalogScalarF64

[elleryjh]

I solved it.  I was able to accomplish this with:

void setup(){
   DAQmxCreateAOVoltageChan(handle,"Dev1/ao1","",-10.0,10.0,DAQmx_Val_Volts,"");
   DAQmxCfgSampClkTiming(handle, "PFI1", 1000, DAQmx_Val_Falling, DAQmx_Val_HWTimedSinglePoint, 1);
}

void changeVoltage(float v){
   DAQmxWriteAnalogScalarF64(handle,true,100.0,v,NULL);
}

I think the problem was referring to "Dev1/PFI1" instead of just "PFI1" - it doesn't know where to look when I give it the device name. 

[Miko42]

Thanks Elleryjh for your post!! 

I was able to solve my problem with your indication.