Have a 2 question about system configuration

Dear Jeff.kim,

1. booksize ALMs contain the pre-charge device on board. In Chassis-units the pre-charge device is outsourced on AIM. Therefore you don't need a terminal for control signals on booksize.

In booksize a line contactor is optional. There is a function module for line contactors implemented. So you can apply a digital output of CU320-2 to control the line contactor. It is closed BEFORE pulses are enabled. You can verify sequence control in LH1:

https://support.industry.siemens.com/cs/ww/en/view/109760366

 Please note that in case you don't apply a line contactor you always have ~540V DC-link voltage even when switched OFF1.     

2. yes, centering is a good idea. And yes, you need to ensure max capacity of DC-link bars of each module in the chain. In your configuration I rather fear you exceed total power capacity of infeed. Nevertheless if you never apply full load on all MoMos simultaneous or just in partial load this configuration should work.