10-11-2012 01:48 AM - edited 10-11-2012 02:13 AM
I'm using DAQmxReadBinaryI16 to read 8 channels data & save to file.
I modify the ContAcq-IntClk-EveryNSamplesEvent.proj, by changing
DAQmxErrChk (DAQmxReadAnalogF64(taskHandle,nSamples,10.0,DAQmx_Val_GroupByScanNumber,data,nSamples*numChannels,&numRead,NULL));
to
DAQmxErrChk (DAQmxReadBinaryI16(taskHandle,nSamples,10.0,DAQmx_Val_GroupByChannel,databuf,nSamples*numChannels,&numRead,NULL));
To scan 8 channels data, I set
DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai7:0","",DAQmx_Val_Cfg_Default,min,max,DAQmx_Val_Volts,NULL));
Samples per Channel = 5000
Sample rate = 5000
I run the scanning for hours & save all 8 channels data (in short) everysecond.
I found data of 1 channel looks like this after 1 hour scanning.
First graph is plotting data from Channel 1, 2, 3, with same input.
Second graph is plotting data from Channel 2.
part of the data (in short & in double)
chan 1 chan 2 chan 3 chan1 chan2 chan3 <-- after scalling using ScaleCoef
-162 | -161 | -161 | 0.073428 | 0.073757 | 0.073757 |
-159 | -161 | -160 | 0.074415 | 0.073757 | 0.074086 |
-159 | -160 | -159 | 0.074415 | 0.074086 | 0.074415 |
-159 | -159 | -159 | 0.074415 | 0.074415 | 0.074415 |
-158 | -159 | -157 | 0.074744 | 0.074415 | 0.075073 |
-172 | -27 | -164 | 0.070138 | 0.117849 | 0.07277 |
-161 | -162 | -158 | 0.073757 | 0.073428 | 0.074744 |
-170 | -329 | -164 | 0.070796 | 0.018478 | 0.07277 |
-185 | -224 | -174 | 0.06586 | 0.053027 | 0.06948 |
-184 | -155 | -185 | 0.066189 | 0.075731 | 0.06586 |
-205 | -191 | -193 | 0.059279 | 0.063886 | 0.063228 |