242 Rockwell Automation Publication 520-UM001K-EN-E - August 2021
Appendix G Safe Torque Off Function
PowerFlex 525 Safe-
Torque-Off Operation
The PowerFlex 525 Safe-Torque-Off function disables the drive’s output IGBT’s
by breaking the link with the drive microcontroller. When used in combination
with a safety input device, the system satisfies the requirements of EN ISO
13849 and EN62061 for safe-torque-off and helps protect against restart.
Under normal drive operation, both safety inputs (Safety 1 and Safety 2) are
energized, and the drive is able to run. If either input is de-energized, the gate
control circuit becomes disabled. To meet EN ISO 13849 operation, both safety
channels must be de-energized. See the following examples for more
information.
Verify Operation Test the safety function for proper operation after the initial setup of the
PowerFlex 525 Safe-Torque-Off function. Retest the safety function at the
intervals determined by the safety analysis described on page 239
.
Verify that both safety channels are functioning according to the table below.
Discrepancy Time of the Safety Inputs
For example, if S1 is disabled and S2 did not follow after the discrepancy time,
fault F111 “Safety Hardware” will occur. However, if S1 is disable and S2 follows
before the discrepancy time, fault F059 “Safety Open” will occur.
The discrepancy time is one second for PowerFlex 525 FRN 5.xxx and later. The
discrepancy time is 10 milliseconds for PowerFlex 525 FRN 4.xxx and earlier.
IMPORTANT
By itself, the Safe-Torque-Off function initiates a coast to stop action.
Additional protective measures will need to be applied when an
application requires a change to the stop action.
Channel Operation and Verification
Safety Function
Status
Drive In
Safe State
Drive In
Safe State
Drive In
Safe State
Drive
Able To Run
Drive Status
Configured by t105
[Safety Open En]
Fault F111
(Safety Hardware)
Fault F111
(Safety Hardware)
Ready/Run
Safety Channel Operation
Safety Input S1 No Power Applied Power Applied No Power Applied Power Applied
Safety Input S2 No Power Applied No Power Applied Power Applied Power Applied
IMPORTANT
If an external fault is present on the wiring or circuitry controlling the
Safety 1 or Safety 2 inputs for a period of time, the Safe-Torque-Off
function may not detect this condition. When the external fault
condition is removed the Safe-Torque-Off function will allow an enable
condition. Fault in the external wiring shall either be detected by
external logic, or excluded (wiring must be protected by cable ducting or
armoring), according to EN ISO 13849-2.
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