s71500 power fail even if supplied from PS

we have the below s71500 hardware installed. we supplied 24vdc power only to the PS module. but the CPU displayed power fail, and could not detect the memory card. so we supplied 24vdc also to the CPU, then all was ok. 

question: doesn't the CPU get all its internal power from the PS through the inner backplane bus?

Hi,

Try to check the "No connection to supply voltage L+" option under the CPU properties.

Regards

Hello Ziemens,

Could you please tell us what you get as result if you check the mentionned option and only supply the PS module ? did you solve your problem ?

Regards

the PS power is not enough to supply all the 22 modules at its right side. the problem was solved by supplying external 24 vdc to the PS and also to the CPU.