In rare occurances technicians may remove the bottom terminal from the AS or I/O Baseplate so that a power supply can fit. The backpanes inside the baseplates are not al the same and this will not work.
Visually determine which baseplate is for each module.
SmartStruxure Power Supply
SmartStruxure Automation Server
SmartStruxure I/O module
Incorect baseplate will not work on the SmartStruxure modules.
See picture for representation of Power Supply backplane, the other configuration is for Automation Server (and I/O modules).
For more detailed information please see the Hardware Reference Guide.