Sir, we are having a problem in Siemens Sinamics G120 power module 240  and contol unit CU240E. 

After Drive power ON and OFF, control unit LED no flashing and Display searching the parameter. 

When change the control unit 240E with new one. The new control unit becomes failed and no display. 

Then we fix old control unit again it is going on searching parameters. And no LED flashing. 

Please help us to understand the reason and root cause. 

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Split from G120 problems.

Try providing 24V power to the CU externally rather than providing it when the PM 240 powers on and provides 24VDC to the CU.

I find it helps a great deal figuring things out because you can remove the CU from the drive and still communicate with it using Starter (or StartDrive) to see what's going on inside the drive.  The last problem(s) with a drive are saved, and the control unit current state will tell you whether it is bad or ok.

Jindal Mithu

Sir, we are having a problem in Siemens Sinamics G120 power module 240  and contol unit CU240E. 

After Drive power ON and OFF, control unit LED no flashing and Display searching the parameter. 

When change the control unit 240E with new one. The new control unit becomes failed and no display. 

Then we fix old control unit again it is going on searching parameters. And no LED flashing. 

Please help us to understand the reason and root cause.