Fig.4-7:
Contact travel diagram for panic
Information
At the KeTop, the enabling switches always feature two circuits.
To meet the safety category 3 PL d in accordance with EN ISO 13849-1, the
enabling switch must be realized with 2 circuits and these circuits have to be
monitored on short circuits.
The safety category 3 PL d means, that one failure must not lead to the loss
of the safety function, and whenever possible, the single failure is detected.
chapter 4.5.2 "Example of Connection with PILZ
PNOZ s6.1 Control Relay" on page 31
shows how the safety category 3 PL
d can be fulfilled by the enabling switch up to the output terminal K4 within the
connection box. The entire concept of the machine must be laid out according
to the principles of safety category 3 PL d.
The monitoring of the simultaneity by the control relay is necessary, because
otherwise maybe a failure culmination would not be recognised and this would
cause the loss of safeness:
Example:
If one circuit of the enabling device switches to the enabled state as a result
of a failure and after some time the second circuit also switches to the enabled
state as a result of an failure, then no de-energisation by the enabling device
would be possible.
Further the EN 60204-1 prescribes that the enabling switches shall be con-
nected to a category 0 stop or a category 1 stop, that means the energy must
be switched off.
For calculation of the PL for the safety function "enabling" the PL- and B
10d
-
values of all involved components have to be included. For details for calcu-
lating the PL for the whole safety function see EN ISO 13849-1, chapter 6.3,
appendix H and appendix I.
Connection
KeTop T50VGA
© KEBA 2009
User's Manual V1.50
30