Siemens SINAMICS Series Function Manual page 40

Controlling the safety functions
5.2 Control of "STO" and "SS1" via terminal module for option K82
Recommended application
This option is used when the following requirements apply:
● Activation will be executed isolated in a voltage range of 24 VDC - 230 VAC.
● Using non-shielded control lines which are longer than 30 m.
● The devices are deployed in plants dispersed over a wide area (no ideal equipotential
bonding).
Principle of operation
Two independent channels of the integrated safety function are controlled via relays (K41,
K42).
Relay K41 controls the signal at the Control Unit that is necessary for the safety function and
relay K42, the corresponding signal at the Motor Module.
The selection and deselection must be simultaneous. The time delay that is unavoidable due
to mechanical switching processes, for example, can be adapted via parameters. p9650
specifies the tolerance time within which the selection/deselection of the two monitoring
channels must occur in order to be considered as "simultaneous".
The circuit is structured so that it is protected against wire break, i.e. if the relay's control
voltage fails then the safety function is active.
A checkback signal can be derived for information, diagnostics or troubleshooting from the
normally-closed contacts of the relay switched in series.
Wiring of the checkback signal can be performed optionally and is not part of the safety
concept.
Note
The checkback signal is not necessary for compliance with the standard DIN EN ISO 13849-
1 (formerly EN954-1) cat. 3 PL d and DIN EN 61508 SIL2.
The selection of the safety function must be performed in two channels. A switch according
to ISO 13850/ EN 418, positive opening according to EC 60947-5-1, or a certified safety
controller must be used as actuating element.
Danger to life as a result of failure of the safety functions through unsuitable selection of the
actuating element
An unsuitable actuating element may cause the safety function to fail which can result in
death or serious injury.
• Select the correct actuating element for the purpose of compliance of the overall system
40
WARNING
with the required standard (DIN EN ISO 13849-1 (formerly EN954-1) Cat. 3 PL d or DIN
EN 61508 SIL2).
Safety Integrated
Function Manual, 07/2016, A5E03264275A