SIEMENS
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Siemens D 11 · 2015
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Function
(continued)
2
Highlights
Safety Integrated
Safe Stop 1 (SS1)
The SS1 function causes a motor to stop rapidly and safely and
switches the motor to torque-free mode after coming to a stand-
still, i.e. STO is activated.
Activation
The SS1 function can safely stop the drive in accordance with
EN 60204-1, Stop Category 1. When the SS1 function is se-
lected, the drive brakes autonomously along a quick-stop ramp
and automatically activates the Safe Torque Off and Safe Brake
Control functions (if configured) when the parameterized safety
delay time expires.
Application
The SS1 function is used when, in the event of a safety-relevant
incident, the drive must stop as quickly as possible with a sub-
sequent transition into the STO state (e.g. EMERGENCY STOP).
It is thus used to bring large centrifugal masses to a stop as
quickly as possible for the safety of the operating personnel, or
to brake motors at high speeds as quickly as possible. Exam-
ples of typical applications are saws, grinding machine spin-
dles, centrifuges, winders and storage and retrieval machines.
Customer benefits
The targeted stopping of a drive by means of SS1 reduces the
risk of danger, increases the productivity of a machine, and al-
lows the safety clearances in a machine to be reduced. The prin-
ciple is to bring the drive actively to a standstill, compared with
just using the STO function. Complex mechanical brakes that
are susceptible to wear are not normally required to brake the
motor.
Safe Stop 2 (SS2)
The SS2 function brings the motor to a standstill quickly and
safely and then activates the SOS function once the motor has
stopped.
Activation
The Safe Stop 2 function can safely stop the drive in accordance
with EN 60204-1, Stop Category 2. When the SS2 function is se-
lected, the drive brakes autonomously along a quick stop ramp.
In contrast to SS1, the drive control remains operational after-
wards, i.e. the motor can supply the full torque required to main-
tain zero speed. Standstill is safely monitored (Safe Operating
Stop function).
Application
As with SS1, the SS2 function ensures the quickest possible de-
celeration of the motor. However, the motor power is not
switched off. Instead, a control system prevents it from leaving
the standstill position – even if it is affected by external forces.
Typical applications for SS2 include machine tools, for example.
Customer benefits
The SS2 function ensures a rapid axis stop. Because the control
remains active, after the safety function is deselected, produc-
tive operation can continue without referencing. This ensures
short setup and standstill times and high productivity.
STO
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G_D211_XX_00305
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G_D211_XX_00306
SOS
© Siemens AG 2015