Reading voltages into a USB6210 using CVI

Question

I have had this board working ok until I connected it to some other equipment.
the first 3 inputs are connected to load cell amps and the fourth to measure the output of the test machine appling load to the load cells.
Its when I conect to this test machine the voltages go all over the place.
I have the inputs wired in differential mode.
I got into Test panels and selected differential then ran the program, then selected create a task so I could select four inputs and all the channels read ok.
So what I think I need is some way to configure my code to set the USB6210 to be in differential mode.
I have searched the NI examples and can not find an example.
this is the code I use to set up the USB6210
 int32       error=0;
 TaskHandle  taskHandle=0;
 char        chan[256];
 float64     min=-10.0,max=10.0,rate=10000;
 uInt32      sampsPerChan=100;
 int32       numRead,a;
 uInt32      numChannels;
 float64     *data=NULL;
 int         log;
 char        errBuff[2048]={'\0'};
 uInt32      i;
 float  Floatnum;
 char NumString[30]; 
  // DAQmx Configure Code
  DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
  DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai1,Dev​1/ai2,Dev1/ai3,Dev1/ai4","",DAQmx_Val_Cfg_Default,​min,max,DAQmx_Val_Volts,NULL));
  DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",rate,DAQmx_Va​l_Rising,DAQmx_Val_FiniteSamps,sampsPerChan));
  DAQmxErrChk (DAQmxGetTaskAttribute(taskHandle,DAQmx_Task_NumCh​ans,&numChannels));
  if( (data=malloc(sampsPerChan*numChannels*sizeof(float​64)))==NULL )
   MessagePopup("Error","Not enough memory");
   goto Error;
  // DAQmx Start Code
  DAQmxErrChk (DAQmxStartTask(taskHandle));
Solved!
Go to Solution.

Answer 1

You may have to use:
DAQmxSetChanAttribute (taskHandle, "", DAQmx_AI_TermCfg, DAQmx_Val_Diff, 0);
This will affect all channels in the task.
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