Emergency Stop Of Multiple Drives - Category 3, Pl D, Sil2 - Danfoss VLT AutomationDrive EZ FC 321 Operating Manual

Safe Torque Off
Operating Guide
• Any non-safety related standards should be fulfilled for the application and its components.
• The application designer is responsible for selecting suitable components.
• The cable shown in bold in
• To fulfill PL e, the MTTFd and DC for the entire safety function has to be calculated.
This setup can be used if a dual positive switching device is used.
Implementation in SISTEMA using Danfoss VLT library
As an example, use the block "VLT® AutomationDrive EZ FC 321 (Terminal 37)". It is not necessary to edit all the parameters which
are set in the library.
SB monitoring
SB emergency
safety relay:
stop device
MSR 33
Illustration 7: Safety-related Block Diagram

5.5 Emergency Stop of Multiple Drives - Category 3, PL d, SIL2

FC
12
37
Illustration 8: Multiple Drives with Category 3, PL d, SIL2
1 Safety relay (Category 3, PL d, or SIL2)
2 Emergency stop button
Safety function
If there is an emergency, the emergency stop device is activated. The STO function in the drive is activated. Following a stop or an
emergency stop command, the drive is halted.
If it is required to control multiple drives from the same control line, the STO inputs may be interconnected directly.
Connecting the inputs increases the probability of a fault in the unsafe direction since a fault in 1 drive may result in all drives be-
coming enabled. However, the probability of a fault is so low, at 1 x 10
requirement for SIL2 for a realistic number of drives. Do not connect more than 20 inputs in parallel.
Danfoss A/S © 2022.11
Illustration 6 has to be short-circuit protected according to ISO 13849-2, table D.4.
SB stopping devices
CH channel 1
BL FC 300 safe stop
(terminal 37)
from Danfoss VLT library
CH channel 2
BL output
contactor:
100S-C
FC
12
37
FC
12
37
4
3 Reset button
4 Short-circuit protected cable (if not inside an instal-
lation IP54/NEMA 12 cabinet). See ISO 13849-2, Ta-
ble D.4 for further information.
-10
per hour, that the resulting probability still meets the
AQ355238304444en-US0301 / 130R0955 | 17
Application Examples
3
1
2