Hello all,
I try to make a buffered counting with counter0 of my PXI card 6220, to count the speed of a motor through a photocell and a sticker over the pulley of the motor.
I have wired my photocell at PFI8 (source) and I generate a pulse train that I have wired in PFI9.
The input to the counter is a pulse train 5V high level - 0V low level.
The problem is that the counter counts sometimes more than 1 pulse for every turn of the motor. However, apparently the pulse train looks ok.
I don´t know what´s the problem.
The rising slope of the pulses looks very nice so, I think I could discard it.
I can suppose that in between pulses there are some glitches at a very high frequency that I cannot see (I have sampled this signal only at 800kHz and at this frequency there are no glitches), but maybe the counter yes, because it works at 20MHz.
Somebody has experienced this problem. Sometimes ago, using a PCI6221, I solved a similar problem by activating the digital filtering, but it seems it is not possible to activate for this cards. Could somebody confirm it?
Any ideas will be appreciated.
Thank you very much in advance!!
