Safely-Limited Speed (Sls); Variable Safely-Limited Speed (Sls); Safe Maximum Speed (Sms); Prevention Of Unexpected Start-Up (Pous) - ABB FSO-21 User Manual

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Safely-limited speed (SLS)

This safety function prevents the motor from exceeding user-defined speed limits. If
the motor speed reaches the positive or negative SLS trip limit, the FSO module
activates the SSE function and the motor stops. See section
(SLS) on page 127.
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Variable Safely-limited speed (SLS)

This safety function prevents the motor from exceeding user-defined speed limits.
With the Variable SLS function, the speed limits can be changed on the fly. The speed
limits are controlled from a safety PLC via the PROFIsafe communication bus. See
section Variable Safely-limited speed (SLS)
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Safe maximum speed (SMS)

This safety function is used to protect the machine from too high speeds/frequencies.
You can configure it to be permanently on or off. If the motor speed reaches the
minimum or maximum SMS trip limit, the FSO module activates the SSE function and
the motor stops. There are two different versions of the SMS function. See sections
• SMS function, version 1
• SMS function, version 2
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Prevention of unexpected start-up (POUS)

This safety function prevents the machine from starting accidentally. The POUS
function activates the drive STO function. See section
start-up (POUS) on page 145.
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Safe speed monitoring (SSM)

This safety function provides a safe output signal to indicate whether the motor speed
is between user-defined limits. See section
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Safe direction (SDI)

This safety function monitors that the motor rotates into the correct direction. If the
motor rotates into the forbidden direction more than the user-defined SDI tolerance
limit allows, the FSO module activates the SSE function and the motor stops. This
safety function requires that you use an encoder in the safety application. See section
Safe direction (SDI)
on page 143
on page 143.
on page 151.
on page 137 and chapter PROFIsafe.
and
Prevention of unexpected
Safe speed monitor (SSM)
Overview 43
Safely-limited speed
on page 147.