level numbering

Hi again

i have a profilux 4, i have at the moment 3 level switch connected, one with splitter cable. I also have an expansion box 1, i would like to know at what level number i start with the expansion box? number 5?
levels 1-4 are for the the p4 plugs?

Thanks.

The P4 includes support for up to 4 Level sensors, built into 2 ports.
Port 1 - Level1/2
Port 2 - Level 3/4

If you get an expansion box, the first Level port would become Level 5/6.