Safe limited speed status only mode – Rockwell Automation 21G PowerFlex 750-Series AC Drives Reference Manual User Manual
Page 91
Rockwell Automation Publication 750-RM001F-EN-P - February 2012
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Safe Limited Speed (SLS) Modes
Chapter 7
Safe Limited Speed Status
Only Mode
When properly configured for Safe Limited Speed Status Only, the safety option
provides Safe Limited Speed status information in addition to the Safe Stop
functions as described in
.
When the Safe Limited Speed input (SLS_In) is OFF, the feedback velocity is
monitored and compared against a configurable Safe Speed Limit. If the
measured velocity exceeds the limit, no stopping action takes place. Instead, the
system status is made available as a safe output intended for a safety
programmable logic controller (PLC).
You can program an optional P53 [LimSpd Mon Delay] to delay the start of Safe
Limited Speed monitoring.
Safe Limited Speed monitoring is requested by a transition of the SLS_In input
from ON to OFF. If you configure a P53 [LimSpd Mon Delay], the delay begins
when Safe Limited Speed monitoring is requested by the SLS_In input transition
from ON to OFF. The safety option begins monitoring for Safe Limited Speed
when the delay times out. The SLS_Out output is ON if Safe Limited Speed
monitoring is active and the speed is below the configured Safe Speed Limit,
considering hysteresis.
Figure 25 - Timing Diagram for Safe Limited Speed Status Only
TIP
In Safe Limited Speed Status Only mode, Door Monitoring and Enabling Switch
Monitoring are not available.
ATTENTION: When the safety option is properly configured for Safe Limited
Speed Status Only mode, it will not automatically initiate a Safe Stop in the
event of an overspeed condition.
Low
Threshold
(1)
SLS_In
SLS_Out
SLS
Request
P55 [Safe Speed Limit]
Speed
Time
SLS Monitoring Delay:
P53
Safe Limited Speed
Active
SLS Request
Removed
(1) Low Threshold = (P56 [Speed Hysteresis]/100) x P55 [Safe Speed Limit]