Remedied from?
9400 HighLine SW V5.0
Eliminated function restriction
Due to a function restriction the drive automatically restarted after a drive error or STO ('Safe torque off') although auto-start was inhibited after connecting to the mains (C00142=0) if a motor brake was controlled via the basic LS_Brake function (C2580<>0) because this automatically cancelled the inverter enable in the 'Error', 'Fault', and 'STO' device states. The result was that the 'Device is ready to start' state was reached without stopping when returning from these states. Due to revision the 'Device is ready to start' state is not reached without stopping anymore even if a motor brake is controlled via the basic LS_Brake function (C2580<>0).
Which products are affected?
9400 HighLine SW ≤ V4.1
What happens?
The drive is restarted automatically after a fault or STO (Safe torque off) although the automatic restart is inhibited after mains connection (C00142 = 0). If the inverter is only inhibited by the brake control (and not from another source in addition), the axis can be moved directly by the enabled basic function.
Expected behaviour:
If the automatic restart is inhibited after power on (C00142 = 0), the device control of the enabled controller must stop until the inverter has once been inhibited and enabled again after mains switching, trouble, fault or STO in the 'ready to switch on' state. If the trouble state covers a period shorter than 500 ms, the device is restarted automatically.
When does the problem occur?
The behaviour only occurs if a motor brake is controlled via the basic function 'LS_Brake' (C2580 <> 0). As a result, the controller enable is automatically changed back to the device states fault, trouble and STO which leads to the behaviour that the 'device is ready to switch on' state is executed without stopping when returning from the states mentioned before.
In addition, the call up interval of the application task influences the behaviour. In case of a 1 ms application task interval the device control stops as expected in the 'device is ready to switch on' when returning form the 'fault' state. The behaviour only occurs when returning from the states STO and trouble. In case of a 2 ms interval the behaviour occurs when returning from the states STO, trouble and fault.
Note:
An automatic return from the 'trouble' state can e.g. also be possible when in case of a control board supplied with 24 V the DC bus voltage assumes permissible values again after low voltage (LU) or overvoltage (OU) has been detected.
Possible diagnostics?
If the behaviour described above occurs the brake control is to be deactivated for test purposes via the 'LS_Brake' function. If this has been done the device control should afterwards stop as expected in the 'device is ready to switch on' state.
Short-term measures/recommendations?
None. If the LS_Brake function is used to control the motor brake, the automatic restart is not inhibited reliably.
Evaluation:
In case of applications in which an automatic restart is to be inhibited, this is checked during commissioning. However, the behaviour cannot be detected reliably since the interactions of the conditions are very complex. The protection of persons cannot be implemented even if the restart inhibit works correctly.
The automatic restart is avoided as expected with the parameters of the Lenze setting.
