User Documentation

4 System description of safe power-feed modules | Modules switchable by PF-O-xDI-SIL
18 1484600000/07/11.2020u-remote IP20 modules for functional safety manual
4.3 Modules switchable by PF-O-xDI-SIL
Safely switchable output modules:
– UR20-4DO-P
– UR20-4DO-P-2A
– UR20-4DO-PN-2A
– UR20-8DO-P
– UR20-8DO-P-2W-HD
– UR20-16DO-P
– UR20-16DO-P-PLC-INT
– UR20-4DO-N
– UR20-4DO-N-2A
– UR20-8DO-N
– UR20-2PWM-PN-0.5A
– UR20-2PWM-PN-2A
– UR20-4AO-UI-16
– UR20-4AO-UI-16-HD
– UR20-4AO-UI-16-DIAG
– UR20-4AO-UI-16-DIAG-HD
In case a N-switching output module is positioned within a
safety segment the connected load needs to be switched
against +24V Safe.
The relay output modules UR20-4RO-CO-255 and UR20-
4RO-SSR-255 are not safely switchable, therefore they must
not switch any safety function.
The digital counter module UR20-1CNT-1DO-100 will not be
switched since it is supplied via the input current path.
4.4 Conguration
A PF-O-xDI-SIL module can be positioned anywhere in
the u-remote station. Multiple PF-O-xDI-SIL modules
and thus safety segments can be set up in a single station.
When planning a u-remote station with PF-O-xDI-SIL
modules, the following requirements must be met:
– The overall current consumption from the system current
path of all switchable modules within a safety segment
must be lower than 100mA (see table in section4.5).
– Each safety segment might include at most 12 switcha-
ble modules.
– The switch-off delay time for the safe input channels
within a safety circuit is 500ms ± 10ms.
– The load output is not designed for either inductive or
capacitive loads.
– The feed-in of the PF-O-xDI-SIL module must be
safeguarded with a 8-A super fast fuse.
– A SELV/PELV power supply must be used.
– The safely shut-off systems/applications must get their
power exclusively from the safe feed-in module
PF-O-xDI-SIL. Likewise, it must not be possible to
feed external energy into the safety segment elsewhere.
– Relay modules can be located within a safety segment,
however their outputs cannot be safely shut off in case of
a malfunction.
– At the SS1 output of the UR20-PF-O-2DI-DELAY-SIL, only
systems/equipment that do not feed any power back into
the system in the event of a malfunction can be con-
nected.
– Any external short circuits in the wiring of the safe output
must be avoided.
– Fault exclusion as per EN ISO13849-2 must be provided.
4.5 Switch-off delay time
The turn-off time of a PF-O-xDI-SIL module is 20ms,
caused by the hardware and rmware delay time. The time
required until the output voltage even of the last switchable
module of a safety segment is below 5V, can be calculated
as follows:
Turn-off time of a PF-O-xDI-SIL module
+ Sum of all modules’ hardware delay
= Switch off delay [ms]
Switch-off delay and current consumption
Hardware delay [ms] Current consumption
from I
SYS
[mA]
UR20-4DO-P
2 8
UR20-4DO-P-2A
2 8
UR20-4DO-PN-2A
3 15
UR20-8DO-P
1 15
UR20-8DO-P-2W-HD
1 15
UR20-16DO-P
1 10
UR20-16DO-P-PLC-INT
1 10
UR20-4DO-N
2 8
UR20-4DO-N-2A
2 8
UR20-2PWM-PN-0.5A
5 10
UR20-2PWM-PN-2A
5 10
UR20-4AO-UI-16
150* 10
UR20-4AO-UI-16-HD
150* 10
UR20-4AO-UI-16-DIAG
150* 10
UR20-4AO-UI-16-DIAG-HD
150* 10
*The delay time is always 150ms, irrespective of the amout of these modules.