The slots in the standard frames are predefined slots for the different elements a synchronous machine controller may have, i.e., the voltage regulator, the power system stabilizer, etc. The names of the input/output signals for each slot must match the DSL Model (ElmDsl) assigned to the slot. This means that if you create your own model, the names of the input and output signals in your new block diagram have to match the inputs/outputs of the slot, whereby not all signals of the slot have to be used in the inserted block diagram or vice versa.