PXI-5421, C++, Creating output signal, DAQmxWriteAnalogF64 fails

Question

I want to create a simple sine wave output on a PXI-5421 card. I have looked at the sample projects for DAQmx, and based an application on them.
The application falls over at the call to DAQmxWriteAnalogF64 using the following parameters:
lReturn = DAQmxWriteAnalogF64(
m_hTask,
1000,
0,
10.0,
DAQmx_Val_GroupByChannel,
data,
&lWritten,
NULL
What am I doing wrong?
Below is the output of the application, and the code.
***** START OF OUTPUT *****
DAQmxResetDevice -> SUCCESS
DAQmxCreateTask -> SUCCESS
DAQmxCreateAOVoltageChan -> SUCCESS
DAQmxCfgSampClkTiming -> SUCCESS
Samples per channel written: 0
Source terminal to be routed could not be found on the device.
Make sure the terminal name is valid for the specified device. Refer to Measurement & Automation Explorer for valid terminal names.
Device: PXI1Slot3
Property: DAQmx_SampClk_Src
Source Terminal:
Task Name: _unnamedTask<0>
Status Code: -200040
DAQmxWriteAnalogF64 -> -200040
***** END OF OUTPUT *****
***** START OF APPLICATION *****
void Startup( void )
// get amplitude
double dblAmplitude = 5; // 5 volts
// generate wave data
float64 data[1000];
for( int i=0; i<1000; i++ )
data[i] = dblAmplitude * sin( (double)i * 2.0 * PI/1000.0 );
// device, channel and terminal names
char szDeviceName[128];
strcpy(szDeviceName,"PXI1Slot3"); // PXI1Slot3
char szChannel[128];
sprintf(szChannel,"%s/ao0",szChannelName); // PXI1Slot3/ao0
char szTerminal[128];
strcpy(szTerminal,"Onboard Clock"); // Onboard Clock
// reset device
long lReturn = DAQmxResetDevice(szDeviceName);
_AddToLog("DAQmxResetDevice",lReturn);
// create task
lReturn = DAQmxCreateTask("",&m_hTask);
_AddToLog("DAQmxCreateTask",lReturn);
// if that worked...
if(lReturn==0)
// create output voltage channel
lReturn = DAQmxCreateAOVoltageChan(
m_hTask,
szChannel,
-1 * dblAmplitude,
dblAmplitude,
DAQmx_Val_Volts,
NULL
_AddToLog("DAQmxCreateAOVoltageChan",lReturn);
// if that worked...
if(lReturn==0)
// define sampling
lReturn = DAQmxCfgSampClkTiming(
m_hTask,
szTerminal,
10*1000,
DAQmx_Val_Rising,
DAQmx_Val_ContSamps,
1000
_AddToLog("DAQmxCfgSampClkTiming",lReturn);
// if that worked...
if(lReturn==0)
// write to buffer
long lWritten = 0;
lReturn = DAQmxWriteAnalogF64(
m_hTask,
1000,
0,
10.0,
DAQmx_Val_GroupByChannel,
data,
&lWritten,
NULL
CString strLine;
strLine.Format("Samples per channel written: %d",lWritten);
_AddToLog(strLine);
_AddToLog("DAQmxWriteAnalogF64",lReturn);
// if that worked...
if(lReturn==0)
// start task
lReturn = DAQmxStartTask(m_hTask);
_AddToLog("DAQmxStartTask",lReturn);
else
// clean up
_CleanUp();
void _CleanUp( void )
// stop task
long lReturn = DAQmxStopTask(m_hTask);
_AddToLog("DAQmxStopTask",lReturn);
// clear task
lReturn = DAQmxClearTask(m_hTask);
_AddToLog("DAQmxClearTask",lReturn);
***** END OF APPLICATION *****

Answer 1

Broccoli wrote:
I want to create a simple sine wave output on a PXI-5421 card. I have looked at the sample projects for DAQmx, and based an application on them.
The application falls over at the call to DAQmxWriteAnalogF64 using the following parameters:
lReturn = DAQmxWriteAnalogF64(
m_hTask,
1000,
0,
10.0,
DAQmx_Val_GroupByChannel,
data,
&lWritten,
NULL
What am I doing wrong?
Below is the output of the application, and the code.
***** START OF OUTPUT *****
DAQmxResetDevice -> SUCCESS
DAQmxCreateTask -> SUCCESS
DAQmxCreateAOVoltageChan -> SUCCESS
DAQmxCfgSampClkTiming -> SUCCESS
Samples per channel written: 0
Source terminal to be routed could not be found on the device.
Make sure the terminal name is valid for the specified device. Refer to Measurement & Automation Explorer for valid terminal names.
Device: PXI1Slot3
Property: DAQmx_SampClk_Src
Source Terminal:
Task Name: _unnamedTask<0>
Status Code: -200040
DAQmxWriteAnalogF64 -> -200040
***** END OF OUTPUT *****
***** START OF APPLICATION *****
void Startup( void )
// get amplitude
double dblAmplitude = 5; // 5 volts
// generate wave data
float64 data[1000];
for( int i=0; i<1000; i++ )
data[i] = dblAmplitude * sin( (double)i * 2.0 * PI/1000.0 );
// device, channel and terminal names
char szDeviceName[128];
strcpy(szDeviceName,"PXI1Slot3"); // PXI1Slot3
char szChannel[128];
sprintf(szChannel,"%s/ao0",szChannelName); // PXI1Slot3/ao0
char szTerminal[128];
strcpy(szTerminal,"Onboard Clock"); // Onboard Clock
// reset device
long lReturn = DAQmxResetDevice(szDeviceName);
_AddToLog("DAQmxResetDevice",lReturn);
// create task
lReturn = DAQmxCreateTask("",&m_hTask);
_AddToLog("DAQmxCreateTask",lReturn);
// if that worked...
if(lReturn==0)
// create output voltage channel
lReturn = DAQmxCreateAOVoltageChan(
m_hTask,
szChannel,
-1 * dblAmplitude,
dblAmplitude,
DAQmx_Val_Volts,
NULL
_AddToLog("DAQmxCreateAOVoltageChan",lReturn);
// if that worked...
if(lReturn==0)
// define sampling
lReturn = DAQmxCfgSampClkTiming(
m_hTask,
szTerminal,
10*1000,
DAQmx_Val_Rising,
DAQmx_Val_ContSamps,
1000
_AddToLog("DAQmxCfgSampClkTiming",lReturn);
// if that worked...
if(lReturn==0)
// write to buffer
long lWritten = 0;
lReturn = DAQmxWriteAnalogF64(
m_hTask,
1000,
0,
10.0,
DAQmx_Val_GroupByChannel,
data,
&lWritten,
NULL
CString strLine;
strLine.Format("Samples per channel written: %d",lWritten);
_AddToLog(strLine);
_AddToLog("DAQmxWriteAnalogF64",lReturn);
// if that worked...
if(lReturn==0)
// start task
lReturn = DAQmxStartTask(m_hTask);
_AddToLog("DAQmxStartTask",lReturn);
else
// clean up
_CleanUp();
void _CleanUp( void )
// stop task
long lReturn = DAQmxStopTask(m_hTask);
_AddToLog("DAQmxStopTask",lReturn);
// clear task
lReturn = DAQmxClearTask(m_hTask);
_AddToLog("DAQmxClearTask",lReturn);
***** END OF APPLICATION *****
Hello Broccoli,
NI-DAQmx is not a supported API for the NI-5421 AWG. For all NI Signal Generators, please use the NI-FGEN API, which shipped with your instrument. You may also download NI-FGEN (2.2.1 as of today) from
http://digital.ni.com/softlib.nsf/954feaeea92d90918625674b00658b83/8b1f32b4b8f7148586256efd006075a9?OpenDocument
You should find helpful C examples bundled with NI-FGEN that will make using the NI-5421's full capabilities very easy.
Marcos Kirsch
Signal Generators Software Engineer
Marcos Kirsch
Principal Software Engineer
Core Modular Instruments Software
National Instruments