Emergency Stop Applications
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
2.1-23
2.1
Features
Dual-channel operation with
detection of shorts across contacts
Monitored reset with falling edge
Contact expansion through PNOZ s7
(contact expander module) and positi-
ve-guided contactors
Feedback loop to monitor contact ex-
pansion
Description
E-STOP function
When the E-STOP pushbutton S3 is
operated, the input circuit on the safety
relay PNOZ s4 (K4) is interrupted, the safety
contacts on K4 open. As a result the input
circuit on the contact expander module
PNOZ s7 (K5) is interrupted, the safety
contacts on K5 open. Contactors KM1 and
KM2 de-energise.
Settings on the unit
The connector between the safety relays
PNOZ s4 (K4) and PNOZ s7 (K5) must be
connected.
The operating mode selector switch
(mode) on the safety relay PNOZ s4 must
be set to “Monitored reset, falling edge
with detection of shorts across contacts
(In2-)”.
PL e of EN ISO 13849-1, SIL 3 of EN 62061
PNOZ s7 - Combined with PNOZ s4
Start/reset
The safety relay PNOZ s4 (K4) can be
started by pressing reset button S4 if:
E-STOP pushbutton S3 has not been
operated and
The safety contacts on the contact
expander module PNOZ s7 (K5) are open
Contactors KM1 and KM2 have de-
energised and
The feedback loop on the contact
expander module PNOZ s7 (K5) is
closed.
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 (K4).
The feedback loop on the safety relay PNOZ
s4 (K4) is connected to the feedback loop
on the contact expander module
PNOZ s7 (K5).
Safety assessment
The safety relays K4 and K5 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 relays PNOZ s4 (K4) and
PNOZ s7 (K5) can be started when the
input circuit at K4 is closed first, followed
by reset button S4. This avoids an
Pilz products
Number
Designation
Order number
1
PNOZ s4
750 104
1
PNOZ s7
750 107
1
PITestop Set1.1
400 410
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 K4
open. This fault condition can only be
rectified by switching the supply voltage
on the safety relay PNOZ s4 (K4) off and
then on again.
