LabVIEW Encoder not reliably returning Rate

[wireties]

This was our fix for exactly the same problem. We created our own encoder class and put in this PIDGet method:

double RhsEncoder:IDGet()
{
double dfNewRate;
double dfNewCount = pQuadrature->GetDistance();
double dfNewTime = GetClock();

if (pQuadrature->GetStopped())
{
dfNewRate = 0.0;
}
else
{
// calc the rate

if((dfNewTime - dfLastTime) == 0.0)
{
dfNewRate = 0.0;
}
else
{
dfNewRate = (dfNewCount - dfLastCount)/(dfNewTime -
dfLastTime);
}
}

dfLastTime = dfNewTime;
dfLastCount = dfNewCount;
return(dfNewRate);
}


HTH