Nice ROBO600 Instructions And Warnings For Installation page 8

d - Place the gearmotor on the foundation plate

e - Fit the provided washers and nuts and hand tighten
them
f - Check that the gearmotor is correctly positioned on the
foundation plate
g - Open the gate fully by hand
h - Rest the first section of rack on the gearmotor's
pinion: make sure that it corresponds to the start of the
gate section and that there is a gap of 1-2 mm between
the rack and the pinion itself (this is to prevent the gate
loading the gearmotor shaft

6 – English
1÷2 mm