Siemens SINAMICS S120 Function Manual page 436

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Function modules

9.3 Extended Brake Control

Example 1: 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.

Now, only the brake opening time will delay the motor starting to rotate following activation of

the master switch. If the master switch is moved (deflected), then there is a "setpoint enable

from the control" (bit interconnected with p1142, r1229.3, p1224.0). The speed controller is

enabled immediately. Once the brake opening time has elapsed (p1216), the speed setpoint is

enabled. When the master switch is in the zero position, the speed setpoint is inhibited and the

drive brakes along the deceleration ramp of the ramp-function generator. The brake closes

when the speed drops below the standstill limit (p1226). After the brake closing time (p1217),

the speed controller is inhibited (no motor force!). The extended brake control is used.

Example of operating brake for a crane drive

Example 2: 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.

Function Manual, 06/2019, 6SL3097-5AB00-0BP2

Drive functions