Nice ROBO600 Instructions And Warnings For Installation page 10

m - Cut any excess rack off the end
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06. Slide the gate open and closed by hand to check that the rack is properly aligned with the pinion.
N.B.: make sure that there is a gap of 1-2 mm between the rack and pinion for the entire length of the gate
07. Vigorously tighten the nuts to fasten the gearmotor to the
foundation plate
08.
Install the OPEN and CLOSE limit switch brackets: proceed in the same way for each limit switch
OPEN:
a - Slide the gate open by hand, stopping it 2/3 cm before the mechanical stop
b - Slide the limit switch bracket along the rack in the open direction until the limit switch trips (you will hear it click)
c - After you hear the 'click', move the bracket further forwards by 2 cm (minimum)
d - Secure the bracket to the rack with the provided grub screws
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8 – English
1÷2 mm
2-3 cm