Safe limited speed output (sls_out) – Rockwell Automation 21G PowerFlex 750-Series AC Drives Reference Manual User Manual
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Rockwell Automation Publication 750-RM001F-EN-P - February 2012
Chapter 4
Speed Monitoring I/O Signals
If the Safe Stop Type is initiated or if a Safe Stop is initiated due to a fault, the
SS_Out output is turned OFF.
If an error is detected on either channel of the dual-channel output, a fault occurs.
I/O faults are Stop Category faults, which initiate the configured Safe Stop Type.
The fault is latched until the safety option is successfully reset.
For more information on faults, refer to
.
Safe Limited Speed Output (SLS_Out)
The safe state for this signal in all cases is OFF.
The SLS_Out output functionality is determined by the configured Safety mode.
If the SLS_In is ON and a successful Safe Stop or Safe Limited Speed reset is
performed, the SLS_Out turns ON in all Safe Limited Speed modes except Safe
Limited Speed Status Only.
For the Safe Limited Speed modes (SLS), the SLS_Out is used to interconnect
speed monitoring safety options in multi-axis applications. For SLS_Out to
SLS_In cascaded signals, the interface is a dual-channel sourcing solid state safety
output connected to a dual-channel safety input configured as OSSD. The
outputs are read back and pulse-tested when the P73 [SLS Out Mode] parameter
is configured for pulse-testing.
For a single unit system or the last unit in a cascaded system, the SLS_Out is
intended to be connected to an input of a safety programmable logic controller
(PLC). The same PLC could also control the Safe Stop function with a safe PLC
output connected to the Safe Stop input (SS_In).
For the first or middle units in a cascaded system, the SLS_Out is intended to be
connected to the Safe Limited Speed input (SLS_In) of the next safety option in
the cascaded system. This lets one SLS switch enable Safe Limited Speed on all
axes at the same time.
IMPORTANT
If you disable pulse-testing on this output, the achievable SIL, Category, and PL
ratings of your entire safety system are reduced.