Rockwell Automation Publication PFLEX-UM003D-EN-P - June 2021
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General Description
General Description
The DriveGuard® Safe Torque Off option, when used with PowerFlex® 40P or
PowerFlex 70 drives together with other safety components, provides a safety
function which inhibits torque generation in the motor(s) powered by the drive. When
used with PowerFlex 40P or PowerFlex 70 drive, the DriveGuard Safe Torque Off option
has been certified to meet the requirements for SIL 2 according to EN/IEC 61800-5-2
and IEC 61508, and PL (d) and Category 3 according to EN ISO 13849-1. The DriveGuard
Safe Torque Off option is just one component in a safety control system. Components
in the system must be chosen and applied appropriately to achieve the desired level
of safeguarding.
What Is the DriveGuard Safe Torque Off Option?
The DriveGuard Safe Torque Off option:
•
Provides the “Safe torque off (STO)” function defined in EN/IEC 61800-5-2.
•
Blocks gate firing signals from reaching the IGBT output power devices of the
drive. This prevents the IGBT’s from switching in the sequence necessary to
generate torque in the connected motor.
•
Can be used in combination with other safety devices to fulfill the requirements
of a system “safe torque off” function which satisfies Category 3 / PL (d)
according to EN ISO 13849-1 and SIL CL 2 according to EN/IEC 62061, IEC 61508,
and EN/IEC 61800-5-2.
IMPORTANT
This option is suitable for performing only mechanical work on the drive
system or affected area of a machine. It does NOT disconnect or isolate the
drive power output to the motor.
This option should not be used as a control for normal starting and/or
stopping the drive.
