672PCI 6723 error when attempting to generate DO signal with 20kHz sample clock

[VJohnson]

I have a piece of code that successfully worked on the PCI-6224 card, but when I tried to implement the same code on the PCI-6723 card I have run into problems.

Here is the code that I am using:

ManchConversion6723();//produces SendIt array of series of 1s/0s

// DAQmx Configure Clock
DAQmxErrChk (DAQmxCreateTask("",&taskHandleFRQ));
DAQmxErrChk (DAQmxCreateCOPulseChanFreq(taskHandleFRQ,"Dev3/ctr0","",DAQmx_Val_Hz,DAQmx_Val_Low,0,20000,0.5));
DAQmxErrChk (DAQmxCfgImplicitTiming(taskHandleFRQ,DAQmx_Val_ContSamps,72));
	
// DAQmx Configure Digital Output
DAQmxErrChk (DAQmxCreateTask("",&taskHandle));MessageBox("D");//vj
DAQmxErrChk (DAQmxCreateDOChan(taskHandle,"Dev3/port0/line0","",DAQmx_Val_ChanPerLine));MessageBox("E");//vj
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"/Dev3/Ctr0InternalOutput",20000,DAQmx_Val_Rising,DAQmx_Val_ContSamps,72));

// DAQmx Write Code
DAQmxErrChk (DAQmxWriteDigitalLines(taskHandle,72,0,10.0,DAQmx_Val_GroupByChannel,SendIt6723,NULL,NULL));

// DAQmx Start Code
DAQmxErrChk (DAQmxStartTask(taskHandleFRQ));
DAQmxErrChk (DAQmxStartTask(taskHandle));

When I arrive at the DAQmxCfgSampClkTiming line, I receive an error stating:

DAQmx Error: Measurements: Requested value is not a supported value for this property.

Property:DAQmx_SampTimingType

You Have Requested: DAQmx_Val_SampClk

You Can Select: DAQmx_Val_OnDemand

Task Name: _unnamedTask<0>

Status Code: -200077

 I believe the problem stems from the source variable of the function. I am simply tring to send the data out at the 20KHz rate.

Any help would be greatly appreciated. Thanks in advance!

[VJohnson · Accepted solution]

Nevermind. Seems as though the PCI-6723 does not contain correlated DIO channels. In other words, sample clocks can not be tied to the DIO channels to allow for digital waveform generation. According to the AO Series User Manual, this applies to NI 6731/6733 Only. The error was trying to tell me that only a single transmit or receive channel was allowed.

For this reason, I will just stick with my PCI-6224 card. 

Sorry for the confusion.