Allen-Bradley PowerFlex 525 User Manual page 214

Appendix G Safe-Torque-Off Function
214
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 (S13-S14 & S21-
S22) to the Minotaur monitoring safety relay unit. The output circuits (13-14 &
23-24) will cause the Safe-Torque-Off Enable circuit to trip and the motor 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 loss of the safety function.
Example 2 – Safe-Torque-Off Connection with Controlled Stop Action,
SIL 2/PL d
Stop Category 1 – Controlled
(1)
GuardMaster
Trojan
Gate
+24V DC
A1 S21 S11 S52 S12 S22 37 47 57
Minotaur
MSR138DP
A2 X1 X2 X3 X4 Y39 Y40 3 4 5
24V DC
Common
(1) Safety relay and PowerFlex 525 must be installed in the same enclosure.
Rockwell Automation Publication 520-UM001A-EN-E - February 2013
Stop
Start
13 23 S33 S34
14 24 Y2 Y1
AC line
input power
PF 525
+24V DC
Stop
Start
Gate control
power supply
Gate control
circuit
S1
S2
M