Sinamics S120 problem during saving RAM to ROM

Hello,

I know it's an old topic but I just came across an issue with this alarm.

I'm doing a propulsion systems with S120LC ALM of 1400KW and S120LC MoMo of 1200KW with the CU320-2PN version 4.6.

During commissioning I did stationary identification and speed optimization with encoder and it was successful.

Did a RAM to RAM that the alarm appear. we didn't do the Power On or P972 to 1 immediately.

We test the drive in speed mode and also Torque control because they have to do Fast Load reduction in case the generator on the ship is overloaded. all successful,

Problems appear when we decided to do hardware reset P972=1 to remove this alarm. The torque mode was not working anymore, we had instability on the torque feedback and when we were switching for speed to torque the motor is overspeeding like it's not following the torque setpoint.

We had re-do identification of the motor and speed optimization to come back to normal but the alarm came back with ram to rom .

Do you know if the problem is solve with version 4.7

Where are doing the P972 to 1 only in the control unit drive object, but P972 exist in the Infeed ALM DO and Vector DO.

Propulsion system is very critical and torque mode is essential .

Have you heard about this problem

Martin Plouffe

Siemens Canada

Hi, 

I have exactly same problems with torque after power on! One drive give negative torque with positive current! 

How did you solve the problem? 

Luca

If you selected copy ram to ram on the starter, and made a power cycle on the inverter you lost the parameters you programmed. So to torque control would not work properly.