Corrected from:
9400 HighLine V15.00.09
9400 Servo PLC V09.00.09
Response of the new version:
In the event of a fail-QSP, no stopping torque is stored. In C2606 Minimum starting torque a minimum precontrol torque can be defined which is not fallen below.
What happens?
When the brake is released via the LS_Brake holding brake control, an unexpected torque is precontrolled when the drive was previously stopped via QSP.
When does this behaviour occur?
The behaviour occurs under the following conditions:
Holding brake control via the LS_Brake system block is activated: Operation mode brake C2580 < > 0
Source of starting torque C2588 = 1: Stopping value
When the drive was stopped last (C2581 was exceeded), the current torque did not correspond to the value required for holding the load.
This may e.g. happen when the drive is blocked or stopped by QSP.
Which products are affected?
9400 HighLine V08.24.00
9400 Servo PLC V04.15.00
Short-term measures:
If you cannot exclude scenarios in which a torque that considerably differs from the required holding torque is saved, the automatic storage of the last holding torque should not be used.
In this case, select the feedforward control torque via the fixed values Starting torque 1/2 (C2586 and C2587) and select C2588 = 0 as Source of starting torque.
Evaluation/recommendations:
By automatically saving the current torque in the worst case, it is also possible that a torque in the opposite direction could be precontrolled to the actually required holding torque. In this case, an active load could be accelerated 'downwards' when the brake is released. In this event, speed and position control would then first have to build up a correction torque to counteract this.
