I have a (knockoff?) Omron E6B2-CWZ6C incremental rotary encoder with 1800 P/R. It has 3 channels ABZ. Whenever I upload a code to my Arduino Leonardo, my encoder always have a little "spring effect" near 0 when my board is plugged in. When it is off power, I can turn the shaft perfecly fine, but after plugging in, and start turning the encoder, it works nice, but something kinda blocks it, I can turn it over that "bump" but of coure it will regiser in he movement. It does it with every code I tried. Why could it be?
Also, why Z channel does not matter? I had a code with 3 output I had some with having only 2 but no difference. What is Z channel for?