WARNING!
●
Not fully functional emergency stop devices may have fatal consequences!
Emergency stop switches which are red-yellow marked must be effective
under all circumstances in all operating modes of a machine or plant.
Store handheld terminals with not operational red-yellow emergency stop
switches on a place where the operator cannot see it, so that he can not
mistake the device.
Handheld terminals which are plugged in and out frequently for temporarely
use, must not have a red-yellow emergency stop switch. Such devices must
be equipped with a grey stop switch.
●
Resetting an activated emergency stop facility must not result in uncontrol-
led start-up of machines or installations.
●
The emergency stop button does not replace other safety facilities.
●
The emergency stop button on the handheld terminal does not replace the
emergency stop buttones to be mounted directly on the machine.
●
Some mechanical errors in emergency stop switches can be recognized at
operation only.
Test the function of the emergency stop switch when the device had been
exposed to mechanical shock (e.g. it had been fallen on the ground).
Additionally the emergency stop switch must be tested cyclic (6 monthly).
Watch the machine stopping after the emergency stop switch had been
pushed.
●
For further informations to emergency stop switch observe
Conformity, Directives and Standards" on page 132
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 activated.
The enabling switch consists of a 3-position operating element and an sepa-
rated evaluation electronics. An essential feature are the continuous two-
channel circuits beginning from the actuating elements up to the connecting
terminals. For the evaluation circuits different technologies and circuits are
used. Due to the electronic switching contacts, their lifetime does not depend
on the load provided the nominal values of the load (ohmic, inductive and ca-
pacitive) 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 circuits
and overload.
Circuit 1: thermal protective circuit
Circuit 2: fold back line
Connection
KeTop T50VGA
© KEBA 2009
User's Manual V1.50
28