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NI 6602 how to synchronize frequency counter

Hi, i'm working with a NI 6602 board. Actually we have 3 optical encoder connected to ctr0 (pfi38), crt1(PFI34)  and ctr2(PFI30). I need to have synchronous acquisition of frequency. I'm using NI-DAQMX with C . Our goal is to display frequency variation between the 3 entry.

I think using  edge count can be a better way to have synched samples but actually i can't change wiring and cannot connect my source signal to pfi39, pfi35 and pfi31.  I've tried to use  DAQmxSetCICountEdgesTerm(taskHandle,"Dev2/ctr0","Dev2/PFI38") , i have the error  -89120 (signal can't be routed). When i set  DAQmxSetCICountEdgesTerm(taskHandle,"Dev2/ctr0source","Dev2/PFI38") no error but always count 0.

My signal frequency is betwenn 0 and 16000hz.

 

 

My code is below

DAQmxErrChk (DAQmxCreateCOPulseChanTime(taskHandleOut,
       "Dev2/ctr4",  // gating pulse generated
       "channel 1",
       DAQmx_Val_Seconds, // units
       DAQmx_Val_Low, // resting state
       0.0,  // initial delay
       0.5,  // pulse train freq 0.,
                                                    
          0.5));  // pulse shape
 DAQmxErrChk (DAQmxCfgImplicitTiming( taskHandleOut,
      DAQmx_Val_ContSamps,
      0));

DAQmxErrChk (DAQmxCreateCICountEdgesChan( taskHandle,
       "Dev2/ctr0",
       "channel 0",
       DAQmx_Val_Rising,
       0,   // initial count
       DAQmx_Val_CountUp)); // count direction

 DAQmxErrChk (DAQmxCfgSampClkTiming( taskHandle,
      "/Dev2/Ctr4InternalOutput", // sample clock set to pulse gen
      20000000.0,    // max expected rate of sample clock
      DAQmx_Val_Rising,
      DAQmx_Val_ContSamps,
      10000000));    // buffer size
  DAQmxSetCICountEdgesTerm(taskHandle,"Dev2/ctr0source","Dev2/PFI38");

 

Regards

 

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Hi yipilipi,

 

To make edge count, you need to put your signal on the counter sources pin. If not you will not get counts!

 

Regards,

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