Omron Sysmac 20

I have just been given a project to do with a sysmac 20. In the manual it states that internal relays are channels 12 to 15. But in the examples it uses 1000 as an internal relay, which has me a little confused. I would think if I needed a relay that the first one would be 1200, 1201... etc. Has any one here have any experience with these critters? Any help would be greatly appreciated. Thanks in advance.
stv

Any unused I/O relay becomes an internal relay by its lack of use.

OK OK I went to the appendix and it gives the internal relays as 1000 to 1800. I feel stupid for posting this before i checked the appendix.
stv

There is never a stupid question posted. Only stupid answers.:nodi: