Siemens SINAMICS S120 Function Manual page 437

Examples
Starting against a closed brake
When the device is switched on, the setpoint is enabled immediately (if the required enable
signals are issued), even if the brake has not yet been released (p1152 = 1). The factory
setting p1152 = r0899.15 must be separated here. The drive starts to generate torque
against the closed brake. The brake is not opened until the motor torque or current (p1220)
has exceeded braking threshold 1 (p1221). Depending on the type and design of the brake,
the time required to completely open the brake differs. Note that once the braking threshold
torque has been exceeded, the operation enabling signal (p0899.2) is interrupted while the
brake is being opened (p1216) to ensure that the motor current does not exceed the
permissible limit values during this period and/or the motor torque generated does not
damage the brake. Interval p1216 must be set on the basis of the time the brake actually
requires to release.
Emergency brake
In the case of emergency braking, electrical and mechanical braking should be realized at
precisely the same time. This can be achieved by using OFF3 as a tripping signal for
emergency braking:
p1219[0] = r0898.2 and p1275.00 = 1 (OFF3 to "Close brake immediately" and invert signal).
To ensure that the frequency converter does not operate against the brake, the OFF3 ramp
(p1135) should be set to 0 seconds. Regenerative energy can be generated, which must be
either fed back to the line supply or dissipated by means of a braking resistor.
Service brake on crane drives
For cranes with manual control, it is important that the drive responds immediately when the
control lever is moved (master switch). The drive is switched on with an ON command
(p0840) (the pulses are enabled). Speed setpoint (p1142) and speed controller (p0856) are
inhibited. The motor is magnetized. The magnetization time required for three-phase motors
(1-2 s), therefore, no longer applies.
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Function modules
8.3 Extended Brake Control
437