Siemens SINAMICS S120 Function Manual page 173

Figure 4-27 Gearbox switchover with increased position tolerance
Diagnostics
The selected gearbox stage is displayed for diagnostic purposes in parameter r9720, bits 24
to 26.
The selected gearbox stage is displayed for diagnostic purposes in parameter r9720, bit 27.
"Safe gearbox switchover" and referencing
The gearbox stage switchover means that the reference position and the user agreement are
lost. This means that after a gearbox switchover, initial referencing is required, to return to
the "safely referenced" state (see Chapter "Safe referencing (Page 190)").
Safety Integrated
Function Manual, 12/2018, 6SL3097-5AR00-0BP1
Description of Safety Integrated functions
4.2 Safety Integrated Extended Functions
171