Handheld Terminal
Connection
User's Manual, Version: 1.3
25
© KEBA 2007
4.5 Enabling Switch
The KeTop is equipped with two enabling switches, one at the left and one
at the right side of the device. This allows a left- and right-hand operation of
the enabling switch. Both enabling switches are equivalent and parallel
switched. So for enabling only one of both enabling switches must be acti-
vated.
The enabling switch consists of a 3-position operating element and an
separated evaluation electronics. An essential feature are the continuous
two-channel circuits beginning from the actuating elements up to the con-
necting terminals. For the evaluation circuits different technologies and cir-
cuits are used. Due to the electronic switching contacts, their lifetime does
not depend on the load provided the nominal values of the load (ohmic, in-
ductive and capacitive) are not exceeded.
The switching elements of the enabling switches are protected against re-
versed polarity. The outputs of both circuits are protected against short cir-
cuits and overload.
Circuit 1: thermal protective circuit
Circuit 2: fold back line
4.5.1 Functioning
The actuating element consists of two symmetrically arranged slides. The
position of these slides is detected by electrical switches and transmitted to
the evaluation electronics.
Positions of enabling switch:
Position
Function
Enabling switch
Contacts
1
home position
is not pressed
enabling outputs are open
2
enabling
is pressed
enabling outputs are closed
3
panic
is pressed strong
enabling outputs are open
For the enabling switch, the following switching sequences are possible: