Operating instructions

Functions
5.12 Safety functions
CU240S and CU240E Control Units, FW 3.2
Operating Instructions, 03/2009, A5E02440075B AA
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5.12 Safety functions
5.12.1 Overview
Functional safety
Machine components operated by electrical drives are intrinsically hazardous. If a drive is
incorrectly used or acts in an unexpected manner in the event of a malfunction, not only can
this damage the machine but it can also cause severe injury or death. Functional safety
reduces this risk of accidents caused by machines to an acceptable residual risk.
Integrated safety functions in SINAMICS G120
The CU240S DP-F and CU240S PN-F Control Units feature a range of integrated safety
functions, which are certified in accordance with Cat. 3 to EN 954-1 and SIL 2 to IEC 61508:
Table 5- 89 Integrated safety functions
Abbreviation Description (DE/EN) Function
STO Sicher abgeschaltetes
Moment
Safe Torque Off
The motor is switched safely to zero torque.
SS1 Sicherer Stopp 1
Safe Stop 1
The motor is brought to a controlled standstill.
SLS Sicher begrenzte
Geschwindigkeit
Safely Limited Speed
The speed of the motor is restricted in a controlled manner.
SBC Sichere
Bremsenansteuerung
Safe Brake Control
The motor holding brake is safely controlled.
Basic prerequisites for using fail-safe functions
1. The machine risk assessment (e.g. in compliance with EN ISO 1050, "Safety of
machinery - Risk assessment - Part 1: Principles") allows the use of inverter safety
functions in accordance with SIL 2 or category 3.
2. The speed control of the inverter must function perfectly. Each fail-safe drive (drive =
inverter + motor + brake + driven machine) must be set up in such a way that all
operating procedures performed by the driven machine can be properly monitored and
that the inverter operates below its limit values (for current, temperature, voltage, etc.).
The performance and parameters of the inverter must be compatible with both the
connected motor and the application in question.
3. Once the machine has been successfully commissioned, you must review the typical
operating conditions and operate the machine close to the permissible limit values. The
fail-safe drive must not malfunction under any circumstances.