Corrected from:
- Inverter Drives 8400 StateLine V14.00.00
- Inverter Drives 8400 HighLine V14.00.00
- Inverter Drives 8400 TopLine V14.00.00
Response of the new version:
The setpoint feedforward control works with plausible quantisation even if C653/1 ≤ 12 bits.
Which products are affected?
Inverter Drives 8400 StateLine, HighLine, and TopLine up to the firmware version 12.01.00.00
What happens?
The torque setpoint LS_Motorinterface.nInputTorqueCtrl_a toggles between 0 and 100% during acceleration or 0 and -100% during deceleration. It is presumably noticed that the drive emits heavy control noises when accelerating/decelerating.
When does the problem occur?
The behaviour occurs with the following settings:
• Sensitivity of the setpoint feedforward control C653/1 ≤ 12 bits.
AND
• The sum of the moments of inertia of the motor and load (C273 and C919/1) is greater than zero
Note: If a Lenze motor from the Engineer motor catalogue is loaded, always the motor inertia in C273 is transferred.
Diagnostics options?
Check whether the feedforward control improves if a sensitivity of the setpoint feedforward control
C653/1>12 bits is parameterised.
The feedforward control component can be diagnosed best by recording the torque setpoint LS_Motorinterface.nInputTorqueCtrl_a.
Tip: With a very low gain in the speed controller, the influence of the feedforward control in the torque setpoint becomes clearer.
Short-term measures/recommendations?
• Sensitivity of the setpoint control C653/1 ≤ 12 bits.
Evaluation:
With an increasing reduction of the sensitivity, an increasingly stable feedforward control torque is expected. A toggling precontrol signal between max-min values cannot be used. The behaviour should be detected during commissioning. A remedy can be parameterised.
