Using Emergency Stop; Application Overview - Siemens SINAMICS DCM User Manual

1.2.3

Using EMERGENCY STOP

STO and SS1 are suitable for the EMERGENCY STOP function when the following
preconditions are carefully taken into consideration:
The user must evaluate as to whether an immediate shutdown of the energy feed for STO
does not result in dangerous states (uncontrolled stopping - STOP category 0 according to
EN ISO 13850).
When using SS1, if the line supply fails, the drive can no longer be actively braked - and it
must be taken into consideration that the drive only comes to an absolute standstill at a later
point in time.
Although actuating the EMERGENCY STOP switch disconnects the energy feed to the drive,
for a permanently excited DC motor that is still rotating, a voltage is still present at the
armature terminals corresponding to the speed.
With an EMERGENCY OFF function the system is brought into a no voltage condition after
switching off in an emergency according to IEC 60204-1. The motor must then come to a
complete standstill and the field supply must have been switched off.
EMERGENCY STOP function according to EN ISO 13850:
The function of the EMERGENCY STOP equipment must be designed so that after actuating
the EMERGENCY STOP device, hazardous motion and operation of the machine are
stopped in a suitable fashion without resulting in any additional risks and dangers.
1.3

Application overview

The following recommendations are described in this document:
Stop Category 0 (STO = Safe Torque OFF)
Stop Category 1 (SS1 = Safe Stop 1)
Overview of the various configurations
Switching device
1 3WL circuit breaker
1 power contactor
2x 3WL circuit breakers
2s power contactors
2x power units with
3WL circuit breaker
2x power units with
power contactor
The safety relays used are listed in Recommended safety relays (Page 73).
Application document for functional safety STO, SS1 (ISO 13849-1)
Compact User Manual, 09/2016, A5E34871844AM
STO SS1 Achievable Performance
Level (PL)
Sec. 3.2 Sec. 4.2 d
Sec. 3.3 Sec. 4.3 d
Sec. 5.2 Sec. 6.2 d
Sec. 5.3 Sec. 6.3 e
Sec. 7.2 Sec. 8.2 d
Sec. 7.3 Sec. 8.3 d
Introduction
1.3 Application overview
Achievable Safety
Integrity Level (SIL)
X
X
2
3
X
X
13