How do I tell which level sensor is which?

[MitchM]

As the title says...

I have:

P3 with level sensor hooked up
1 Expansion box without level sensor hooked up, but with a level sensor port
2nd Expansion box with a level sensor hooked up

The level sensor on the P3 is #1 and that is working well, but how do I number the level sensor on the 2nd expansion box? Would it be level sensor #2 or #3?
I've tried both numbers but neither seems to work.

Thank you

[Gunther]

but how do I number the level sensor on the 2nd expansion box? Would it be level sensor #2 or #3?

Asuming you have a PL3 (not ex and not 3.1) the PL has 1+2, the first exbox 3+4 and the 2th one has 5+6
Regardless if there is a connection to a level input or not, all physically avaiable inputs are counted.

[MitchM]

Great, thanks Gunther.
Yes, it is a PL3.