User Documentation

7 Example applications | Dual-channel emergency stop and cable-pull switch monitoring
78 1484600000/07/11.2020u-remote IP20 modules for functional safety manual
7.4 Dual-channel emergency stop and cable-pull switch monitoring
Achievable safety rating Category 4 ENISO13849-1
PLe ENISO13849-1
SIL 3 EN62061/61508
Stop category 0 EN60204-1
Features – Dual-channel monitoring
– Cross-connection detection
– Start button
– Monitoring of external contactors
(EDM)
Safety sensor / operating
mechanism
– Emergency stop button
– Cable-pull switch, latching
Notes – Manual reset
– Autostart is possible if the NC circuits
from K3 and K4 are connected to 3.3
and 3.4.
All examples shown are proposals without
warranty. In any case the operator has to per-
form a safety review of the entire site.
1.1
1.2
1.3
1.4
3.1
3.2
3.3
3.4
4.1
4.2
4.3
4.4
1.1
1.2
1.3
1.4
2.1
2.2
2.3
2.4
3.1
3.2
3.3
3.4
4.1
4.2
4.3
4.4
M
UR20-PF-O-xDI-SIL
S1S2
UR20-4DO-P
L+(+24 V)
K4
K4
K3
K3Reset
K4
K3
M(0 V)
Emergency stopCable-pull switch,
latching
Example application for dual-channel emergency stop and cable-pull switch monitoring
1)
Switchable modules see section4.3
When the emergency stop button is pushed or the cable-pull
switch is activated, the UR20-PF-O-2DI-DELAY-SIL switches
off the 24V supply for the modules
1)
within the safety
segment and thus also contactors K3 and K4. The failure of
a switching element in the emergency stop button or the
cable-pull switch as well as a cross-circuit in their supply
lines does not result in the failure of the emergency stop
mechanism and is detected within the fault-reaction time.
The UR20-PF-O-2DI-DELAY-SIL module switches on the 24V
supply for the modules
1)
within the safety segment if
– the emergency stop button is unlocked
– and the cable-pull switch is unlocked
– and the feedback circuit (NC contacts of K3 and K4) is
closed
– and the start push button has been pushed and released
again.
Contactors K3 and K4 are controlled by the PLC and can
switch on as soon as the UR20-PF-O-2DI-DELAY-SIL has
switched on the 24V supply.