quadrature encoder, velocity

[NU-MA]

Hi,

I am using DAQ 6062E, with BNC 2120. I have a quadrature encoder, and I need to get the position, and velocity. I have modified BNC2120_Quadrature_Encoder vi from NI. I can compute the velocity (delta position/time loop) easily, however this is not very accurate. I need to have a high accuracy velocity, and I think I have to use the second counter to measure the frequency of channel. However, I am not able to calculate the velocity with this method. I have attached my vi. I appreciate if somebody can help.

My encoder is connected to CTR Source 0 (PFI8), and UP_DOWN (P0.6)

I have connected CTR Source 0 (PFI8) to CTR 1 Gate (PFI4)

Thanks!

[WoodenJesus]

I get reasonably accurate velocity from quad encoders by connecting the source of my counter to the internal 20MHz clock then gating said

counter with my index pulse(Z) or either A or B, depending on the speed at which I am running. This will give you a count of time between

revolutions if gating with Z, or it will yield time between X degrees if gating with A or B.