Siemens SINAMICS G150 Operating Instructions Manual page 562

Functions, monitoring, and protective functions
9.3 Extended functions
Extended brake control when braking with feedback
When braking with a feedback signal (p1275.5 = 1), the brake control reacts to the feedback
signal contacts of the brake. If the timer p1216 is greater than the time to the feedback
signal, then the approach is delayed by the corresponding time difference.
In order to be able to approach with as little delay as possible, the opening time set in p1216
must be shorter than the time to the feedback signal. However, if the timer in p1216 is set
shorter, then alarm A07931 "Brake does not open" appears.
Remedy:
1. Activate the "Release with feedback signal" (p1275.6 = 1).
The pulse enable (BO: r1229.3) and setpoint enable (BO: r0899.15) are now independent
of the set timer (p1217, p1216). The associated enable is determined only by the
feedback signal (BI: p1222, BI: p1223). The timers (p1216, p1217) only affect the
warnings A07931 "Brake does not open" and A07932 "Brake does not close".
2. Optional: To make the two warnings stop appearing, set both timers (p1217, p1216) to 0 ms.
Result: The monitoring of the brake and the display of the alarms are switched off.
Example 1: Starting against a closed brake
When the device is switched on, the setpoint is enabled immediately (if other 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 first establishes a torque against the
applied brake. The brake is not released 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 release the
brake differs. It must be taken into consideration that, once the braking threshold torque has
been exceeded, the operation enable signal (p0899.2) is interrupted for the time interval that
the brake is being released (p1216) to ensure that the motor current does not exceed the
permissible limit values during this period and the motor torque generated does not damage
the brake. Time interval p1216 must be set depending on the time the brake actually
requires to release.
This configuration is used, for example, when the drive is connected to a belt that is under
tension (loop accumulator in the steel industry).
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Converter cabinet units
Operating Instructions, 07/2016, A5E03347396A