Emergency Stop Of Drive With Sto, Safety Relay, And Output Contactor - Category 4, Pl E, Sil3 - Danfoss VLT FC Series Operating Manual

Safe Torque Off
Operating Guide
SB emergency
SB safety relay
stop device
Illustration 7: Safety-related Block Diagram

5.4 Emergency Stop of Drive with STO, Safety Relay, and Output Contactor - Category 4, PL e, SIL3

FC
12
37
4
K1
M
Illustration 8: Drive with STO, Safety Relay, and Output Contactor, Category 4, PL e, SIL3
1 Safety relay (Category 4, PL e, SIL 3)
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
emergency stop command, the drive is halted.
Where the safety control system must be in accordance with PL e ISO 13849-1 or SIL3 (EN 62061 and IEC 61508), it requires a 2-
channel stop for the STO function. One channel can be implemented by the STO input on the drive and the other by a contactor,
which may be connected in either the drive input or output power circuits. The contactor must be monitored through an auxiliary-
guided contact, shown as K1 in
Design features
• The circuit can be used up to category 4 and PL e.
• For PL e, the complete safety functions have to be calculated (MTTFd).
• Use basic safety principles.
• Device used for activation of STO and safety relay must be suitable for the selected category, PL or SIL.
When implementing the emergency stop, pay attention to the following tips:
18 | Danfoss A/S © 2021.03
SB FC 300 safe stop
(terminal 37)
from Danfoss
VLT library
3
+24 V
K1
1
K1
2
Illustration 8.
3 Reset button
4 Short-circuit protected cable (if not inside installa-
tion IP54 cabinet). See ISO 13849-2, Table D.4 for fur-
ther information.
Application Examples
AQ313340186453en-00101 / 130R0544