![SIEB & MEYER 0SD4S Series Скачать руководство пользователя страница 89](http://html1.mh-extra.com/html/sieb-and-meyer/0sd4s-series/0sd4s-series_hardware-description_1264955089.webp)
When the circuit includes a feedback signal, it meets the safety requirements for SIL 3
PLe.
Circuit without feedback (SIL 2 intended):
Safety
relay
PNOZ
e1vp
10s
SD4
A1
X_SAFE_0V
Emergency stop
switching device
A2
S22
A7, B7
A5, B5
X70
X_SAFE_A
X_SAFE_B
Y4
S12
S21
S11
+24 V
DC
(SELV)
A4, A6, B4, B6
0V (SELV)
S34
14
24
Y6
Y7
Fig. 73: OSSD safety relay without feedback
Circuit with feedback (SIL 3 intended):
Safety
relay
PNOZ
mm0p
SD4
X_SAFE_0V
Emergency stop
switching device
A7, B7
A5, B5
X70
X_SAFE_A
X_SAFE_B
+24 V
DC
(SELV)
A4, A6, B4, B6
0V (SELV)
A1
A2
IM0
IM1
T1M21
T0M20
O0
O1
I4
X_SAFE_OK1
X_SAFE_OK2
A3
B3
Fig. 74: OSSD safety relay with feedback
Circuit with STO function deactivated
SD4
X_SAFE_0V
X70
X_SAFE_A
X_SAFE_B
G
N
D
VCC24_STO
GND
A1
B1
A7
B7
A5
B5
A2
B2
B4
B6
A4
A6
24
V
24
V
Fig. 75: STO deactivated
89
Drive System SD4S - Hardware Description
Functional Safety