Siemens SINAMICS S150 - Safe Brake Control (SBC)

Safety Integrated Basic Functions
5.3 Safe Brake Control (SBC)
Safety Integrated
Function Manual, 05/2010, A5E03264275A
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5.3 Safe Brake Control (SBC)
General description
The "Safe Brake Control" function (SBC) is used to control holding brakes that function
according to the quiescent current principle (e.g. motor holding brake).
The command for releasing or applying the brake is transmitted to the Motor/Power Module
via DRIVE-CLiQ. The Motor/Power Module then carries out the action and activates the
outputs for the brake.
Brake activation via the brake connection on the Motor/Power Module is carried out using a
safe, two-channel method.
WARNING
The "Safe Brake Control" function does not detect electrical faults or mechanical defects.
The system does not detect whether a brake is worn, for example, or has a mechanical
defect, or whether it opens or closes.
A cable break or a short-circuit in the brake winding is only detected when the state
changes, i.e. when the brake either opens or closes.
Functional features of "Safe Brake Control"
● When "Safe Torque Off" (STO) is selected or when safety monitoring functions respond,
SBC is executed with safe pulse suppression.
● Unlike conventional brake control, SBC is executed via p1215 through two channels.
● SBC is executed regardless of the brake control or mode set in p1215. SBC is not
recommended, however, when 1215 = 0 or 3.
● The function must be enabled using parameters.
● If SBC is enabled, each time "Safe Torque Off" is selected, the holding brake is closed
immediately with forced dormant error detection.
● When the state changes, electrical faults, such as e.g. a short-circuit in the brake winding
or wire breakage can be detected.
● A debounce function can be applied to the terminals of the Control Unit and the
Motor/Power Module in order to prevent incorrect trips due to signal disturbances. The
filter times are set using parameters p9651 and p9851.
Enabling the "Safe Brake Control" function
The "Safe Brake Control" function is enabled via the following parameters:
● p9602 SI enable safe brake control (Control Unit)
● p9802 SI enable safe brake control (Motor Module)
The "Safe Brake Control" function is not triggered until at least one safety monitoring function
is enabled (i. e. p9601 = p9801 ≠ 0).