HI
This is main interface when it work.
I tried to ask the comany and they said that:
"
The init() code contains these lines:
if ( !status )
{
/* Configure to read relative to the next sample to be read. */
status = DAQmxSetReadRelativeTo( m_th, DAQmx_Val_MostRecentSamp );
}
if ( !status )
{
/* Configure to read at offset 0 from next sample, meaning we wait for the next
* sample everytime we try to read a sample. */
status = DAQmxSetReadOffset( m_th, 0 );
}
These functions configure the DAQ card to always wait for the next available sample when it is read, so if you wait too long between reads, it will discard old samples if a new sample comes in.
If you remove these lines, it will keep the old samples around, but if you do not read the samples out of the buffer at least as fast as the sample rate you configure, the driver will throw an error when its internal buffer becomes full. In practice, this usually means that you should read multiple samples at once, to make sure that even if your code is not looping as fast as the DAQ sample rate, it is still reading samples out at the same overall speed as the internal sample rate.
To understand how to configure the DAQ card from C code, the customer should read the NI-DAQmx C Reference documentation, which is included in the NI-DAQmx installation, and is available from the start menu in the NI-DAQmx folder"
I tried to do following their instruction, remove these lines, but nothing change.
it isn't easy for you to check it without device. Anyway, I am so grateful for your care.
