NI-DAQmx -200279 Error

[d-pabs]

I have been running into a problem with the buffer being overwritten.  The same software/code was running on an older Linux computer without a problem (CentOS <3).  Have since installed Suse 11.0 and now receive the buffer error, -200279.  I have attempted to increase our buffer size, but this does nothing. 

Here is a code snippet:

// daqGetMonitors()
//
int daqGetMonitors(int size, double *monRaw)
{
	static int32 read,rc;
	//rc=0;
	printf("rc=%d before DAQmxReadAnalogF64() in daqGetMonitors()\n", (int)rc);
	printf("daqGetMonitors(size=%d)\n", size);
	
	if (!daq_available) return(0);
	
#ifdef USEDAQ    
	// blocking wait until all samples are collected for the current frame
	rc = DAQmxReadAnalogF64(analogTask,size,10.0,DAQmx_Val_GroupByScanNumber,monRaw,4*size,&read,NULL);
	printf("ERROR: rc=%d after DAQmxReadAnalogF64() in daqGetMonitors()\n", (int)rc);
	//if (DAQmxFailed(rc)) return daqError(rc);
#endif
	printf("  read=%d\n", read);
	return (size-read);
}

 Here is a summary of what i have tried to do and the outcome of each:

The error is being generated within daqGetMonitors() when it is called from the main program.  Before I edited any code I got the buffer error code, rc = -200279 within the function daqGetMonitors() as soon as daqGetMonitors() is called.  I get the buffer error before AND after the DAQmxReadAnalogF64() function is called.  In other words, the error exists before daqGetMonitors has a chance to do anything.  In the main program, rc = 0, both before [i]and[/i] after daqGetMonitors() is called indicating no buffer overflow errors. 

In the main program, rc = 0, both before [i]and[/i] after daqGetMonitors() is called indicating no buffer overflow errors.  I tried using rc as an (additional) input argument for daqGetMonitors which eliminates the buffer error before DAQmxReadAnalogF64() is called, but I still get a buffer error immediately after DAQmxReadAnalogF64() is called. 

I cannot make sense of this.  Can anyone suggest what is going on or additional steps to take to solve this?  I have a feeling this is a simple coding error...

Thanks

[jschwartz]

Hi d-pabs,

What hardware are you using? What version of DAQmx are you using?  What are you doing in your code?  Are you doing a continuous acquisition?  How fast are you sampling and how many samples per channel are you reading?  The KnowledgeBase article, Why Do I Get Error -200279 from my DAQmx Read VI or Property Node?, will explain some troubleshooting steps for tracking dow the error 200279.

[d-pabs]

I am using the PCI-6220 with NI-DAQmx 8.0.1.  We are pulling continuous data from a set of amplifiers while acquiring a stream of video data (30 fps) for approximately 6 seconds at a time.  We are collecting 1000 samples per video frame, each of the 4 channels sample at 31 250 Hz.  I have seen that knowledgebase article and have attempted to increase the buffer size with no luck.  I have not attempted to read the data more frequently because this same exact code/program was fully functional prior to a HD failure and the (new) installation of Suse 11.0.  I have no idea why it has all of a sudden "decided" to stop working.

[jschwartz]

HI d-pads,

Is this the exact program from your old system? Your new system might run at a different rate so you may need to pull data from the buffer more quickly. In a continuous acquisition, I typically set the samples to read at about 1/10th of the sample rate for a typical application.  You may need to adjust this up or down depending on your program.