Safe stop types, Safe torque off with standstill checking – Rockwell Automation 21G PowerFlex 750-Series AC Drives Reference Manual User Manual

Page 62

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62

Rockwell Automation Publication 750-RM001F-EN-P - February 2012

Chapter 6

Safe Stop and Safe Stop with Door Monitoring Modes

Safe Stop Types

Use the P45 [Safe Stop Type] parameter to configure the type of stop that the
system executes when a Safe Stop is initiated. A Safe Stop can be initiated by a
transition of the SS_In input from ON to OFF or by the occurrence of a Stop
Category fault.

While the safety option executes the configured Safe Stop Type, it continues to
monitor the system. If a Stop Category fault is detected, the safety option sets the
outputs to a faulted state, but allows for the door control logic to be set to Unlock
if the feedback signals indicate Standstill Speed has been reached.

Safe Torque Off with Standstill Checking

This Safe Stop Type lets you access the hazard area immediately after motion is
detected as stopped rather than waiting until a specific time has elapsed.

When Safe Torque Off with Standstill Checking is initiated, motion power is
removed immediately and the configured Stop Delay P47 [Max Stop Time]
begins. If the configured Standstill Speed is detected any time after the Safe Stop
has been initiated and before the end of the configured Stop Delay, door control
logic is set to Unlock.

If the Standstill Speed is not detected by the end of the configured Stop Delay, a
Stop Speed fault occurs and the door control logic remains set to Lock until
Standstill Speed is detected.

Figure 11 - Timing Diagram for Safe Torque-off with Standstill Checking

(1) This signal is internal, between the safety option and drive.
(2) DC_Out output shown configured as Power to Release. See

Door Control

on

page 67

for more information.

Stop Request

Stop Delay: P47

Safe Torque-off

Active

Door Control
Output Unlock

P48 [Standstill Speed]

SS_Out Output

Motion Power

(1)

Speed

Time

SS_In Input

DC_Out Output

(2)

Stop Command

(1)

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