Is anyone familiar with the automatic needle calibrator #820-10 for a Camalot 1818. It looks like a simple device but when I follow the instructions to create the calibration program all I get is the needle crashing down onto the calibration button. It seems to me that the needle would slowly move down onto the button until it was sensed and that would be considered the "zero" point of the needle. I must be thinking about this wrong. Any help or explanation is appreciated.