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7.7
Dual-channel two-hand monitoring with automatic start
Achievable safety rating
Stop category
Features
Safety sensor/operating
mechanism
Notes
All examples shown are proposals without
warranty. In any case the operator has to per-
form a safety review of the entire site.
L+(+24V)
S2
M (0V)
Example application for dual-channel two-hand monitoring with automatic start
1)
Switchable modules see section 4.3
1484600000/04/06.2017
Category 4
EN ISO 13849-1
PLe
EN ISO 13849-1
SIL 3
EN 62061/61508
0
EN 60204-1
– Dual-channel monitoring
– Cross-connection detection
– Automatic restart
– Monitoring of external contactors
(EDM)
Two-hand switch
The application must be compatible with
the automatic reset function.
UR20-PF-O-SIL UR20-4DO-P
S1
Reset
u-remote IP20 modules for functional safety manual
7 Example applications | Dual-channel two-hand monitoring with automatic start
If one or both switches of the two-hand switch are released,
the PF-O-xDI-SIL switches off the 24 V supply for the
modules
inside the safety segment and thus also for con-
1)
tactors K3 and K4. The failure of a switching element in the
two-hand switch or a cross-circuit in its supply lines does not
result in the failure of the emergency stop mechanism and is
detected within the fault-reaction time. An interruption of the
NC contact by S2 is detected before the next switching cycle
and by S1 when the power is switched on.
The PF-O-xDI-SIL module switches on the 24 V supply
for the following modules
– the two-hand switch is pressed synchronously within
0,5 seconds
– and the feedback circuit (NC contacts of K3 and K4) is
closed.
Contactors K3 and K4 are controlled by the PLC and can
switch on as soon as the PF-O-xDI-SIL has switched
on the 24 V supply. To reset the system, press the reset but-
ton for 0.1 to 2 s after switching on the power supply, even
when automatic reset is used.
1.1
1.1
1.2
1.2
K3
1.3
1.3
1.4
1.4
2.1
2.1
2.2
2.2
K4
2.3
2.3
2.4
2.4
3.1
3.1
3.2
3.2
3.3
3.3
3.4
3.4
4.1
4.1
4.2
4.2
4.3
4.3
4.4
4.4
within the safety segment if
1)
K3
K4
M
81
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