Pepperl+Fuchs VAA-2E-G4-SN Instruction Manual page 20

VAA-2E-G4-SN
Assignment of the connections
Category 4
The occurrence of an error must not result in loss of the safety function.
An accumulation of errors must not result in loss of the safety function
• Connection of two dependent mechanical switches:
Since the short-circuit over the switch is not detected, the lines
between the safety slave and the switch must either be laid with
protection or must be designed as a four-wire line. The switch must be
positively driven so that it is not possible for the contacts to become
fused together.
20
Subject to reasonable modifications due to technical advances.
Pepperl+Fuchs Group • Tel.: Germany +49 621 776-0 • USA +1 330 4253555 • Singapore +65 67799091 • Internet http://www.pepperl-fuchs.com
mechanicaly
protected
1.1
S+1
Channel 1
1.3
S-1
Safety related circuit
mechanicaly
protected
2.1
S-2
Channel 2
2.3
S+2
1.1
S+1
1.3
S-1
four-wire line
2.1
S-2
2.3
S+2
Safety related circuit
Copyright Pepperl+Fuchs, Printed in Germany