Eliminated from:
Inverter Drives 8400 StateLine, HighLine and TopLine from firmware version 12.00.00.00
Behaviour of the new version?
After activation of the 'DC-bus supply with charging connection' option in bit 8 of the MCTRL special settings C2865/1, a charging time of 10s instead of previously 300 ms is taken into consideration for the SU03 monitoring. This renders a DC supply of the inverters via power supply modules with an additional charging current limitation possible.
Which products are affected?
Inverter Drives 8400 StateLine, HighLine and TopLine with a firmware version lower than 12.00.00.00
What happens?
When switching on the power supply of a DC-bus connection system, the 'Too frequent mains switching' SU03 monitoring responds sporadically in the case of 8400 devices.
When does the problem occur?
The SU03 monitoring responds if the charging process of the electrolytic DC bus capacitors is still not completed within 300 ms after the LU threshold has been exceeded (LU off).
The charging process can be considerably longer if the inverters are connected to a DC supply, which limits the charging current at switch-on. This is for instance the case if a DC supply via 9400 power supply modules or 9400 axes > 30 kW is used.
In this constellation, the charging current has a double limitation, firstly in the 9400 device, and secondly in the 8400 DC bus.
Diagnostics options?
By means of an oscilloscope or the PCAN Explorer (LS_MotorInterface.nDCVoltage_a variable), the voltage characteristic of the DC-bus voltage can be recorded.
Short-term measures/recommendations?
None. For a DC supply of the 8400 devices, the charging time constant of the supplying device must be < 300 ms.
Evaluation:
A DC supply of the inverter is not possible with any 9400 device. The earliest time the restriction is detected is during commissioning; possibly it only occurs later during operation. The error message does not imply the actual cause.
