def wheelEvent(self, event):
    delta = event.angleDelta().y()
    self._z_accumulator += delta
    z_goto = (self.wz_current + (self._z_accumulator / 1000))
    self.callback('G1 Z{:0.2f} F100'.format(z_goto))
def wheelEvent(self, event):
    delta = event.angleDelta().y()
    self._z_accumulator += delta
    z_goto = (self.wz_current + (self._z_accumulator / 1000))
    self.callback('G1 Z{:0.2f} F100'.format(z_goto))