8 STO (safe torque off)
8.4
Purpose
As processes become increasingly automated, protecting persons against potentially
hazardous movements is continuously gaining in importance. Functional safety describes
the necessary measures in the form of electrical or electronic devices for the reduction or
elimination of hazards caused by malfunctions. Under normal operating conditions,
protective devices and guards prevent human access to danger areas. However, in
certain operating modes, e.g. during set-up, persons are required to be present in these
danger areas. In these situations, the machine operator must be protected by way of drive-
and control-system-related measures.
The integrated functional safety technology provides the control-system- and drive-
specific conditions for the optimal realisation of protective functions. As a result, planning
and installation become less labour-intensive. The use of integrated functional safety
technology leads to an enhanced machine functionality and availability compared to the
levels achieved by conventional safety technology.
Product manual BL 4000-C
Page 195 of 298