Emergency Stop Applications
5.1-
Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, 73760 Ostfildern, Germany, Telephone: +49 711 3409-0, Telefax: +49 711 3409-133, E-Mail: [email protected]
2011-10
2.1-8
2.1
PL e of EN ISO 13849-1, SIL 3 of EN 62061
PNOZ s4 - Dual-channel operation, contact expansion through contactor
Features
Dual-channel operation with
detection of shorts across contacts
Monitored reset with falling edge
Contact expansion through positive-
guided contactors
Feedback loop to monitor contact ex-
pansion
Description
E-STOP function
When the E-STOP pushbutton S1 is
operated, the input circuit on the safety
relay PNOZ s4 (K1) is interrupted, the safety
contacts on K1 open. Contactors KM1 and
KM2 de-energise.
Settings on the unit
The terminator on the PNOZ s4 (K1) must
be connected.
The operating mode selector switch
(mode) on the safety relay PNOZ s4 (K1)
must be set to “Monitored reset, falling
edge with detection of shorts across
contacts (In2-)”.
Start/reset
The safety relay PNOZ s4 (K1) can be
started by pressing reset button S2 if:
E-STOP pushbutton S1 has not been
operated and
Contactors KM1 and KM2 have de-
energised.
Pilz products
Number
Designation
Order number
1
PNOZ s4
750 104
1
PITestop Set1.1
400 410
Feedback loop
The positive-guided N/C contacts on
contactors KM1 and KM2 are monitored in
feedback loop S12-S34 of safety relay
PNOZ s4 (K1).
Safety assessment
The safety relay PNOZ s4 (K1) and
contactors KM1 and KM2 must be
installed in a single mounting area
(control cabinet) in order to exclude a
short across the output.
Earth faults and shorts between contacts
in the input circuit are detected.
A fault on the device does not lead to the
loss of the safety function.
The safety relay PNOZ s4 (K1) can be
started when the input circuit at K1 is
closed first, followed by reset button S2.
This avoids an unwanted reset before the
input circuit is closed or as a result of the
reset button being overridden.
If the position of the operating mode
selector switch (mode) is changed during
operation, an error message will be
triggered; the safety contacts on K1
open. This fault condition can only be
rectified by switching the supply voltage
on the safety relay PNOZ s4 (K1) off and
then on again.
