Operating Instructions

Safe Torque Off Function
Basic Function Description
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Safe Torque Off Function
Basic Function Description
The Climatix VFD provides a Safe Torque Off (STO) function. It uses dual-channel S1 and S2 signal inputs to turn
off IGBT switching, further preventing the generation of motor torque in order to achieve a safe stop. See the figure
below for the Safe Torque Off function circuit diagram.
The Safe Torque Off function meets the following international standards:
ISO 13849-1: 2015 Category 3 PL d
IEC 61508 SIL2
EN 62061 SIL CL 2
EN 60204-1 Category 0
Fig. 127:
Figure 17-1: The circuit diagram for the Safe Torque Off function
Safe Torque Off Terminal Function Description
The table below describes the STO (Safe Torque Off) related terminal functions.