User Documentation
7 Example applications | Dual-channel safety door monitoring, spring-operated interlock, controlled shutdown with manual reset and emergency stop
86 1484600000/07/11.2020u-remote IP20 modules for functional safety manual 
Achievable safety rating Category 3 ENISO13849-1
PLe ENISO13849-1
SIL 3 EN62061/61508
Stop category 1 EN60204-1
Features  – Dual-channel monitoring
 – Cross-connection detection
 – Manual reset
 – Monitoring of external contactors 
(EDM)
Safety sensor / operating 
mechanism
 – Emergency stop button
 – Position switch with interlock
 – Manual unlocking
Notes  – Exclusion of the fault “Interruption or 
releasing of the activator, error in the 
safety interlock”
 – As soon as the enabling on the 
frequency converter is withdrawn, the 
converter must execute a controlled 
shutdown.
 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
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-2DI-SIL-DLY UR20-4DO-P
K4
K3
K4
K5
K3
S1
S3
S2
S5
S4
L+(+24V)
M (0V)
Reset
K4
K3
Emergency stop
Safety door
(closed)
Unlocking mechanism
Stopp
Converter
Enable
Example application for dual-channel safety door monitoring, spring-operated interlock, controlled 
shutdown with manual reset and emergency stop
1)
 Switchable modules see section4.3
When the emergency stop button is pushed, the 
PF-O-xDI-SIL switches off the 24V supply for the mod-
ules
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 safety door contact as well as a cross-cir-
cuit in their supply lines does not result in the failure of the 
emergency stop mechanism and is detected within the 
fault-reaction time.
After pressing the stop button and the delay time set in the 
UR20-PF-O-2DI-SIL-DELAY, the spring-operated interlock 
can be activated with the unlock button and the safety door 
can be opened. When the power supply is turned off, the 
safety door cannot be opened if the locking mechanism is 
engaged. We recommend using switches with mechanical 
unlocking capabilities.
The UR20-PF-O-xDI-SIL switches on the 24V supply for 
modules
1)
 within the safety segment if 
 – the emergency stop button is unlocked
 – and the safety door is closed
 – and the locking mechanism is engaged
 – 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-xDI-SIL has switched on 
the 24V supply.
7.12   Dual-channel safety door monitoring, spring-operated interlock, controlled shutdown with manu-
al reset and emergency stop










