SIEMENS
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Siemens D 21.4 · 2017
Safety Integrated
Safety Integrated
3
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Function
Safe Direction (SDI)
The SDI function ensures that the drive can only move in the
selected direction.
Effect
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 operator increases
productivity. Without the SDI function, the machine must be safely
stopped during material loading and removal.
Safely-Limited Position (SLP)
The SLP function monitors the axis to ensure that it remains
within the permissible traversing range.
Effect
When SLP is activated, the traversing range limited by the
configured software limit switches is safely monitored. If the
permitted traversing range is exited, a configurable fault
reaction occurs. It is possible to toggle between two traversing
ranges, even when the machine is in operation.
Application
SLP is used for applications in which machine operators have to
enter a protection area, e.g. for feeding in and removing material.
Safe monitoring of the axis position ensures that the axis cannot
move into the protection area released for operators and so place
them in danger, for example, on storage and retrieval machines,
gantry cranes or machining centers.
Customer benefits
SLP can be used for highly-effective protection area monitoring.
The function does away with the use of external components
such as hardware limit switches and the associated wiring ex-
pense. Due to the short reaction time following a limit overshoot,
safety clearances can be reduced.
SDI
t
v
G_D211_XX_00308
SLP
s
t
G_D211_XX_00310
© Siemens AG 2017