8400 TopLine: FW version = 13.00.00.00
Response of the new version?
The dead time compensation has been corrected.
Which products are affected?
8400 TopLine: FW version ≤ 13.00.00.00
What is the response?
The control of synchronous motors becomes abruptly unstable with an output frequency fout≥650Hz. It is very likely that this trips the response of the OC1 monitoring function.
When does the problem occur?
The response occurs with synchronous motors with a speed feedback, which are actuated in the servo control SM motor control type (C006=1). The rotor position in the motor control in the BaseUnit BU is generated from the current encoder position from the ControlUnit CU and a dead time compensation value for data transmission. Starting from an output frequency fout≥650Hz, this compensation is too small by the factor 2 if the field weakening override point is set to C080=0.
Diagnostics options?
Vibration of the current controller can be recorded by means of the Engineer oscilloscope.
Short-term measures/recommendations?
None.
Evaluation:
Operation of the synchronous machine with f ≥ 650Hz is not possible.
Applications with synchronous motors with a required output frequency fout ≥ 650Hz are rare. The restriction is detected during commissioning.
