SIEMENS
5/3
Siemens PM 21 · 2017
Safety Integrated
Overview
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Function
Drive-integrated safety functions with SIMOTION D and
SINAMICS S110/S120
The main functions of the SINAMICS S120 drive system are inte-
grated into the SIMOTION D Motion Control System. The safety
functions of the SINAMICS S120 integrated into the drive can
therefore also be used in combination with SIMOTION D.
SIMOTION D and SINAMICS S110/S120 are characterized by a
large number of integrated safety functions. In combination with
the sensors and safety control generally required for the safety
functionality, they ensure that highly-effective protection for per-
sons and machines is implemented in a practice-oriented man-
ner.
They comply with the requirements of the following safety
categories:
•
PL d and Category 3 according to EN ISO 13849-1
•
SIL 2 according to IEC 61508 and IEC 61800-5-2
Note:
The Safe Brake Test (SBT) diagnostic function meets the require-
ments of Category 2 according to EN ISO 13849-1.
The Safety Integrated functions are generally certified by
independent institutes. You can obtain the corresponding test
certificates and manufacturer's declarations from your Siemens
contacts.
Drive Safety Data Block (DSDB)
The safety functions of a SIMOTION-assigned drive are con-
trolled via PROFIsafe or fail-safe digital inputs directly at the
drive.
Depending on the safety function that is selected, it makes
sense to respond appropriately to the selection of the function in
the SIMOTION user program to avoid limit violations on the drive
end.
Thus, for example, if the SLS function is selected, the speed of
the affected drives must be controlled by SIMOTION in the avail-
able time, under the respective SLS limit value.
If SOS is selected, the relevant axes must be brought to a stand-
still and kept in that state.
The information about which safety function has been selected
and which setpoint speed limit is currently in effect is transferred
via the DSDB. As a rule, the information is transferred from the
drive to the SIMOTION user program.
The selection of the SBT diagnostic function is transferred in the
opposite direction from the user program to the drive.
The integrated safety functions that are currently available are
described in the following. Their functional safety satisfies the re-
quirements 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 diagnostic 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)
Safe Torque Off (STO)
The STO function is the most common and basic drive-inte-
grated safety function. It ensures that no torque-generating
energy can continue to affect a motor and prevents unintentional
start-ups.
Effect
This function is a mechanism that prevents the drive from
restarting unexpectedly, in accordance with EN 60204-1,
Section 5.4. The STO function disables the drive pulses (corre-
sponds to Stop Category 0 according to 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
protective door is open (restart interlock) and is used on
machines/installations with moving axes, e.g. on handling or
conveyor systems.
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 2017