12
Functional safety
Integrated Safety Technology
Operating Instructions – MOVIMOT
®
flexible
407
12.2
Integrated Safety Technology
12.2.1
MOVIMOT
®
flexible
The safety technology of the decentralized inverter described below has been de-
veloped and tested in accordance with the following safety requirements:
•
Safety Integrity Level 3 according to EN 61800-5-2:2017, EN 61508:2010.
•
PL e according to EN ISO 13849-1: 2015)
This was certified by TÜV Rheinland. Copies of the TÜV certificate and the corres-
ponding report are available from SEW-EURODRIVE on request.
12.2.2
Safe condition
For safety-related operation of the drive unit, Safe Torque Off is defined as safe state
(see STO drive safety function). The safety concept is based on this definition.
12.2.3
Safety concept
The drive unit is supposed to be able to perform the drive safety function "Safe Torque
Off" according to EN 61800‑5‑2:
•
The drive unit can be connected to an external safety controller or safety relay.
This external safety controller/safety relay disconnects the safety-related STO in-
put via a 2-pole 24 V switching signal (sourcing/sinking) when a connected com-
mand device (e.g. emergency stop button with latching function) is activated. This
activates the STO function of the drive unit.
•
An internal, dual-channel structure with diagnostics prevents the generation of
pulse trains at the power output stage (IGBT).
•
Instead of galvanic isolation of the drive from the supply system by means of con-
tactors or switches, the disconnection of the STO input described here safely pre-
vents the control of the power semiconductors in the output stage. The rotary-field
generation for the respective motor is deactivated even though the line voltage is
still present.
•
When the STO drive safety function is activated, the PWM signals generated by
the drive unit are interrupted and not transmitted to the IGBTs.
•
If the STO function detects a discrepancy between both channels, the PWM sig-
nals are inhibited. The inhibit can be revoked by a 24 V reset, or by a device reset
if F_STO_P1 and F_STO_P2 are not controlled with 24 V.
•
The STO drive safety function can be activated externally e.g. via an external
safety device via the STO input.
29128668/EN – 12/2019
