SIEMENS
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Siemens D 11 · 2015
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Highlights
Safety Integrated
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Function
Safety functions integral to the SINAMICS drives
SINAMICS drives are characterized by a large number of inte-
grated safety functions. In combination with the sensors and
safety control required for the safety functionality, they ensure
that highly-effective protection for persons and machines is
implemented in a practice-oriented manner.
They fulfill the following equipment requirements:
•
SIL 2 according to IEC 61508
•
PL d and Category 3 according to EN ISO 13849-1
The Safety Integrated functions of SINAMICS drives are certified
by independent institutions. You can obtain the corresponding
test certificates and manufacturer's declarations from your
Siemens contacts.
The integrated safety functions that are currently available in the
SINAMICS drive system are described below. The functional
safety of all of the functions satisfies the requirements defined in
the international standard IEC 61800-5-2 for variable-speed
drive systems.
The safety functions integrated into the SINAMICS drive system
can be roughly divided into four categories:
•
Functions for safely stopping a drive
- Safe Torque Off (STO)
- Safe Stop 1 (SS1)
- Safe Stop 2 (SS2)
- Safe Operating Stop (SOS)
•
Functions for safe brake management
- Safe Brake Control (SBC)
- Safe Brake Test (SBT) (this function exceeds the scope of
IEC 61800-5-2)
•
Functions for safely monitoring the motion of a drive
- Safely-Limited Speed (SLS)
- Safe Speed Monitor (SSM)
- Safe Direction (SDI)
•
Functions for safely monitoring the position of a drive
- Safely Limited Position (SLP)
- Safe Position (SP) (this function exceeds the scope of
IEC 61800-5-2)
The Safety Integrated Function Manual contains detailed infor-
mation about the safety functions.
Further manuals pertaining to Safety Integrated in drive systems
can be found on the Internet at
133300
Further information about Safety Integrated can be found on the
Internet at
/safety-drives
Safe Torque Off (STO)
The STO function is the most common and basic drive-inte-
grated safety function. It ensures that no torque-generating en-
ergy can continue to affect a motor and prevents unintentional
start-ups.
Activation
This function is a mechanism that prevents the drive from restart-
ing unexpectedly, in accordance with EN 60204-1, Section 5.4.
Safe Torque Off suppresses the drive pulses (corresponds to
Stop Category 0 of EN 60204-1). The drive is reliably torque-
free. This state is monitored internally in the drive.
Application
STO has the immediate effect that the drive cannot supply any
torque-generating energy. STO can be used wherever the drive
will naturally reach a standstill due to load torque or friction in a
sufficiently short time or when "coasting down" of the drive will
not have any relevance for safety.
STO makes it possible for persons to work safely when the pro-
tective door is open (restart interlock) and is used on machines/
installations with moving axes, e.g. on handling or conveyor sys-
tems.
Customer benefits
The advantage of the integrated STO safety function compared
to standard safety technology using electromechanical switch-
gear is the elimination of separate components and the effort
that would be required to wire and service them. Because of the
fast electronic switching times, the function provides a shorter
reaction time than the conventional solution comprising electro-
mechanical components.
STO
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© Siemens AG 2015