Rockwell Automation Publication 520-UM001K-EN-E - August 2021
245
Appendix G Safe Torque Off Function
Example 2 – Safe-Torque-Off Connection with Controlled Stop Action,
SIL 2/PL d
Stop Category 1 – Controlled
(1) Enclosure Recommended. External wiring failure modes must be considered as described in EN ISO 13849-2. Enclosure or
other measure to exclude these failure modes should be used.
Circuit Status
Circuit shown with guard door closed and system ready for normal drive
operation.
Operating Principle
This is a dual channel system with monitoring of the Safe-Torque-Off circuit
and drive. Opening the guard door will switch the input circuits (S11-S12 & S21-
S22) to the Minotaur monitoring safety relay unit. The output circuits (13-14)
will issue a Stop command to the drive and cause a controlled deceleration.
After the programmed delay, the timed output circuits (47-48 & 57-58) will
cause the Safe-Torque-Off Enable circuit to trip. If the motor is rotating when
the trip occurs, it will coast to stop. To restart the drive, the Minotaur safety
relay must first be reset followed by a valid start command to the drive.
Fault Detection
A single fault detected on the Minotaur safety input circuits will result in the
lock-out of the system at the next operation and will not cause loss of the safety
function.
A single fault detected on the PowerFlex 525 safety enable redundant inputs
will result in the lock-out of the drive and will not cause the loss of the safety
function.
24V DC
Common
+24V DC
GuardMaster
Trojan
Stop
Start
A1
S21 S11 S52 S12
A2 X1 X2
13 23
14 24
S33
Y2
S34
Y1
X3
37 47 57
38 48 58
X4
S22
Y39 Y40
Minotaur
MSR138DP
Gate
+24V DC
PF 525
Stop
Start
Gate control
power supply
Gate control
circuit
AC line
input power
S1
S2
M
(1)
Summary of Contents for Allen-Bradley PowerFlex 520 Series
Page 8: ...8 Rockwell Automation Publication 520 UM001K EN E August 2021 Table of Contents Notes ...
Page 68: ...68 Rockwell Automation Publication 520 UM001K EN E August 2021 Chapter 2 Start Up Notes ...
Page 236: ...236 Rockwell Automation Publication 520 UM001K EN E August 2021 Appendix F PID Set Up Notes ...
Page 270: ...270 Rockwell Automation Publication 520 UM001K EN E August 2021 Index Notes ...