Rockwell Automation 20D-P2-DG03 DriveGuard Safe Torque Off Option for PowerFlex 700S Phase II and 700L Drives - Manual (Page 34)

34 Rockwell Automation Publication 20D-UM007G-EN-P - March 2012
Chapter 3 Description of 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 option and the drive 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.
If the Safe Torque Off option sticks ON, the motor will stop on command
due to the enable input. The system cannot be reset when this fault condition
exists.