Automation and Drives
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
A&D SD
STO, SS1 and SLS
alternative wiring
Summary
Safety Standard Drives
Automation and Drives
Why safety functions?
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
In industry, drive inverters are frequently used to control the
speed of electric motors in machines. Generally, these drives
are associated with potentially hazardous motion that must
be safely shutdown using suitable protective equipment and
devices.
This is generally implemented using external circuits that in
some cases can be extremely complex.
Using the safety functions integrated in the SINAMICS G120,
in most cases these external circuits can be eliminated.
Summary
The following examples are implemented according to DIN
EN954-1, Cat. 3.
SINAMICS G120 is TÜV certified according to DIN EN954-1,
Cat.3 and IEC 61508, SIL2.
Automation and Drives
Overview of all A&D SD safety drives
A&D SD
Siemens A&D SD
Standard Drives
SINAMICS G120
SINAMICS G120D (IP65)
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
SIMATIC ET200S FC
SIMATIC ET200pro FC (IP65)
Summary
Certified according to EN 954-1 (Cat. 3) and IEC 61508 (SIL 2)
Automation and Drives
LED indicators on G120 Safety Control Units
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
Safety Digital Inputs
Safety Status LEDs
Automation and Drives
STO (Safe Torque Off)
What is this?
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO is the simplest safety function.
STO, SS1 and SLS
alternative wiring
After STO is activated, the energy supply to the motor is interrupted in a
safety-relevant fashion and as a consequence the motor coasts down
unbraked.
Summary
After STO has been activated it is not permissible that the drive generates
torque – resulting in hazardous motion.
Automation and Drives
STO (Safe Torque Off)
conventionally wired
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
After the Emergency Stop button has been pressed, the contactor safety combination opens
the two line contactors K1 and K2 and the motor coasts down unbraked.
- High wiring time&costs as a result of the safety relay and contactors.
- No protection against manipulation of the safety functions.
- Intensive service is required due to the mechanical shutdown.
- The power-on cycles of the drive inverter have to be taken into consideration as it is
disconnected from the line supply.
- No diagnostics of the drive inverter as the status display is no longer available after
shutdown.
Automation and Drives
STO (Safe Torque Off)
using the safety digital inputs of SINAMICS G120
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
After the Emergency Stop pushbutton has been pressed the firing pulses of the power unit
are cancelled in SINAMICS G120 in a safety-relevant fashion and the drive coasts down
unbraked.
Caution ! The motor is not electrically isolated from the line supply.
+ Cost saving as a result of minimized wiring costs and space-saving as the Emergency Stop
pushbutton is directly connected to the SINAMICS G120 digital inputs without using a
safety contactor combination.
+ Risks are minimized for the plant construction company by using password-protected
safety parameters in SINAMICS G120.
+ No wearing parts as the shutdown is electronic.
+ SINAMICS G120 remains connected to the line supply and its full diagnostics capability is
retained.
Automation and Drives
STO, comparison of the costs using a 1.5 kW drive as
example
A&D SD
Siemens A&D SD
Standard Drives
STO (Safe Torque Off) using the safety digital inputs of the SINAMICS G120:
Generally this connection version of the drives is selected where the drive terminal strip
is used for control and not via Profibus.
Introduction
Conventional wiring:
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
1
1
2
STO, SS1 and SLS
alternative wiring
2
Device
MM440 (without
Profibus and
encoder)
Safety relay
Contactors
Noise suppression
elements
Individual
price
Total price
No. of
connection
points
Space
requirement
(device only)
406
111
17
406
111
34
8
31
12
130
27
30
cm²
cm²
cm²
6
Total
12
£563
0
51
0
187
cm²
cm²
Space
requirement
(device only)
130
130
cm²
cm²
Summary
SINAMICS G120 (with integrated Profibus and encoder interface):
No. of
connection
Individual
Device
price
Total price
points
1
SINAMICS G120
522
522
15
Total
£522
15
Regarding price, wiring costs and space requirement SINAMICS G120 has clear advantages
over conventional wiring.
Automation and Drives
SS1 (Safe Stop 1)
What is this?
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
SS1 using the
SINAMICS G120
as an example
Contrary to STO where the drive coasts down unbraked, for SS1, the drive is
braked down to standstill (zero speed) and is then disconnected from the
power supply in a safety-relevant fashion (STO).
Application examples include machines and plants/systems where hazards
can occur due to motion continuing (e.g. production machines, centrifuges,
vehicles etc.)
Automation and Drives
SS1 (Safe Stop 1)
using conventional wiring
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
After pressing the Emergency Stop pushbutton a fast stop is activated in the drive inverter
via OFF 3 and the drive then brakes.
The contactor safety combination opens the two line contactors K1 and K2 after a time delay
(typ. 3s) (controlled stopping with a safely monitored deceleration time).
- While the drive is stopped using OFF3 motion is not monitored. -> If a fault condition
develops
the drive can accelerate and is only shutdown after the time delay has expired (typ. 3s).
- High wiring costs as a result of the safety relay and contactors.
- It is easy to change the value of the time delay without any specific authorization.
Automation and Drives
SS1 (Safe Stop 1)
using the safety digital inputs of the SINAMICS G120
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
After pressing the Emergency Stop button the Safe Stop 1 safety function in the SINAMICS
G120 is activated and the drive is decelerated using the safety ramp function. At zero speed
(from 2 Hz and below) STO is activated (controlled stopping with safely monitored braking
ramp).
Caution ! The motor is not electrically isolated from the line supply.
+ While the drive is stopping motion is continually monitored. If the drive does not
follow/track the parameterized ramp then STO is immediately initiated.
+ Speed feedback is not required using an encoder for the safety function.
+ Cost saving as a result of minimized wiring costs and space saving as the Emergency Stop
pushbutton is directly connected to the SINAMICS G120 via the safety digital inputs without
safety contactor combination.
+ Risks are minimized for the plant construction company by using password-protected
safety parameters in SINAMICS G120.
Automation and Drives
SS1, comparison of the costs using a 1.5 kW drive as
example
A&D SD
Siemens A&D SD
Standard Drives
SS1 (Safe Stop 1) using the safety digital inputs of the SINAMICS G120:
This connection version is suitable for drives that are controlled via Profibus and if the
safety functions of the plant/system are implemented using an F-CPU.
Introduction
Conventional wiring:
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
1
1
2
STO, SS1 and SLS
alternative wiring
2
Device
MM440 (without
Profibus and
encoder)
Safety relay
Contactors
Noise suppression
elements
Individual
Total price
price
Number of
connection
points
Space
requirement
(only devices)
588
228
17
588
228
34
8
41
12
130
27
30
cm²
cm²
cm²
6
Total
12
£862
0
61
0
187
cm²
cm²
Space
requirement
(only devices)
130
130
cm²
cm²
Summary
SINAMICS G120 (with integrated Profibus and encoder interface):
Number of
Individual
connection
Device
price
Total price
points
1
SINAMICS G120
522
522
15
Total
£522
15
Regarding price, wiring costs and space requirement SINAMICS G120 offers clear
advantages over conventional wiring.
Automation and Drives
SLS (Safely Limited Speed)
What is this?
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
SLS using
SINAMICS G120
as example
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
In this case a safety monitoring function prevents the drive
from exceeding a specified speed (velocity) limit value.
Summary
Application examples include machines where hazards can occur if a
speed/velocity is exceeded (e.g. monitoring the speed of a tool, directly
working at/in a machine in the setting-up mode)
Automation and Drives
SLS (Safely Limited Speed)
using conventional wiring
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
The drive inverter is shutdown if the speed is exceeded.
- Extremely high wiring costs as a result of several safety relays and contactors. A speed
encoder, two initiators and a safety-relevant speed monitor are required to sense the speed.
- There is no protection against the safety functions being manipulated.
- Intensive maintenance & service required as there are many independent monitoring
devices and mechanical shutdown.
Automation and Drives
SLS (Safely Limited Speed)
using the safety digital inputs of the SINAMICS G120
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
After SLS is activated - depending on the parameterized mode - the drive is decelerated to the
parameterized SLS (Safety Limited Speed) or, if the speed is exceeded, STO is activated. In
addition, there is still a second safety function available – such as STO or SS1.
Caution! It is not possible to accelerate to the SLS (Safely Limited Speed) from standstill (zero
speed).
+ Neither external monitoring devices nor speed encoder required as the safety function
is integrated in SINAMICS G120 without any encoder (sensorless).
+ When SLS is activated the deceleration ramp is immediately monitored and the limited
speed. STO is immediately initiated if the drive does not follow/track the parameterized ramp
or the parameterized SLS speed is exceeded.
+ Cost saving through minimum wiring costs and space saving as the safety sensors
(Emergency Stop pushbutton, light curtains etc.) are directly connected to SINAMICS G120
via the safety digital inputs without requiring a safety contactor combination.
+ Risks are minimized for the plant construction company by using password-protected
safety parameters in the SINAMICS G120.
Automation and Drives
SLS, comparison of the costs using a 1.5 kW drive as
example
A&D SD
Siemens A&D SD
Standard Drives
SLS (Safely Limited Speed) using the safety digital inputs of the SINAMICS G120:
This connection version is generally selected for drives that are not controlled via Profibus - but
instead via the drive terminal strip.
Conventional wiring:
Number of
connection
points
Space
requirement
(only devices)
406
111
8
31
130
27
cm²
cm²
241
11
50
cm²
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
1
1
Safely Limited Speed
(SLS)
1
STO, SS1 and SLS
alternative wiring
Summary
1
1
2
2
2
Device
MM440 (without
Profibus and
encoder)
Safety relay
Speed monitor
Cable adapter
between the
encoder and speed
monitor
Encoder
Initiator
Contactors
Noise suppression
elements
Individual
price
Total price
406
111
Approx.
241
Approx.
28
108
31
17
cm²
28
108
62
34
2
0
6
12
25
0
0
30
cm²
cm²
cm²
6
Total
12
£1002
0
70
0
262
cm²
cm²
Space
requirement
(only devices)
130
130
cm²
cm²
SINAMICS G120 (with integrated Profibus and encoder interface):
Number of
Individua
connection
l price
points
Device
Total price
1
SINAMICS G120
522
522
15
Total
£522
15
Automation and Drives
Alternative wiring:
Series sensor circuit
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
It is permissible to activate the safety functions of the SINAMICS G120 via several Emergency
Stop pushbuttons connected in series.
Automation and Drives
Alternative wiring:
Shutting down drives in parallel
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
It is permissible to connect several SINAMICS G120 to a safety circuit.
This allows several drives to be simply combined to form Emergency Stop groups.
Automation and Drives
Summary
A&D SD
Siemens A&D SD
Standard Drives
Introduction
Safe Torque Off
(STO)
Safe Stop 1
(SS1)
Safely Limited Speed
(SLS)
STO, SS1 and SLS
alternative wiring
Summary
Safety-relevant drive applications can be implemented using
SINAMICS G120 with its integrated safety functions, for new
plants/systems as well as in modernizations.
It is possible to implement safety-relevant drive applications
simply and tamper proof.
With our SINAMICS G120 users have a future-orientated drive
inverter that is perfectly embedded in the SIMATIC family via
TIA.