EB 8331-4 EN 3-3
Design and principle of operation
Fig.3-3: Special version with three-key
operation
3.4 Additional equipment
Mechanical limit contacts
The two mechanical limit contacts consist of
two changeover switches. Their switching po
-
sitions are changed independently from one
another by continuously adjustable cam disks.
Theoatingcontactscanbeusedaseither
makeorbreakcontactstoinuencethetasks
of control equipment.
The installation and adjustment of the me-
chanical limit contacts is described in the 'In-
stallation' section.
Electronic limit contacts
The two electronic limit contacts consist of re-
layswithchangeovercontacts.Theoating
contacts can be used as either make or break
contactstoinuencethetasksofcontrol
equipment.
In contrast to the mechanical limit contacts,
the electronic limit contacts no longer function
after a supply voltage failure. The relays are
de-energized and the contacts change to the
idle state.
The installation of the electronic limit contacts
is described in the 'Installation' section. Their
adjustment is described in the 'Start-up and
conguration'section.
The electronic limit contact can be triggered
by the actuator stem position exceeding or
falling below an adjustable switching point.