SIEMENS
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Siemens D 31 · 2015
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Function
Highlights
Safety Integrated
Safe Speed Monitor (SSM)
The SSM function warns when a drive is working below an
adjustable speed limit. As long as it remains below the threshold,
the function issues a safety-related signal.
Activation
If a speed value drops below a parameterized limit, a safety-re-
lated signal is generated. This can, for example, be processed
in a safety controller to respond to the event by programming,
depending on the situation.
Application
With the SSM function, in the simplest case, a safety door can be
unlocked if the speed drops below a non-critical level. Another
typical example is that of a centrifuge that may be filled only
when it is operating below a configured speed limit.
Customer benefits
Unlike SLS, there is no drive-integrated fault reaction when the
speed limit is exceeded. The safe feedback can be evaluated in
a safety control unit, allowing the user to respond appropriately
to the situation.
Safe Direction (SDI)
The SDI function ensures that the drive can only move in the
selected direction.
Activation
Deviation from the direction of motion currently being monitored
is detected reliably and the configured drive-integrated fault
reaction is initiated. It is possible to select which direction of
rotation is to be monitored.
Application
The SDI function is used when the drive may only move in one
direction. A typical application is to permit the operator access
to a danger zone, as long as the machine is rotating in the safe
direction, i.e. away from the operator. In this state, the operator
can feed material into the work zone / remove material from the
work zone without danger.
Customer benefits
The function saves the use of external components such as
speed monitors and the associated wiring. The release of a
danger zone while the machine is moving away from the opera-
tor increases productivity. Without the SDI function, the machine
must be safely stopped during material loading and removal.
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SDI
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© Siemens AG 2014