How to count the pulses of an incremental encoder with PCI-6010?

[YShZh]

Hi everyone,

I am trying to use an incremental encoder and PCI-6010 card to measure the speed of a rotary shaft in Labview 2011. I need to use the counter to count the numbers of the pulses that the encoder generates but I have some problems there to do so.

I connected the encoder signal to the counter source (PFI0) and built a daq assistant block in the Labview (Acquire signals -> Counter Input -> Edge Count -> ctr0) and it is set as shown in the figure. The problem is that no matter how I turn the shaft the measured value will always be 0 although the pulses can be seen very clearly on the O-scope. 

I suppose I must have made a very simple mistake. Could anyone help me on that please?

Thank you.

[Marshall_B]

Hi YShZh,

The current Acquisition Mode setting is set to "1 Sample (On Demand)" and will therefore only ever give you the first count value.  The fist count value is equal to the initial count value, which in your case is 0.

Try changing the acquisition mode to either N Samples or Continuous Samples.

Kind regards,