Connect the outputs (3,4,5,6,7 or 8) on your Digi 001 to the inputs on the RNC. Then connect the outputs of the RNC to an input on the 001 to bring the signal back. So the signal goes
Digi 001 output 3 > Input 1 RNC > Output 1 RNC > Digi 001 Input 4
Under the I/O setup name the output used above "compression send" [You don't have to name the output but it might make more sense if you do]. Name the input that the RNC is coming back through, "compression return". In Pro Tools create an Aux track name this compression return. Also create a audio track to print the compressed sound to.
Now we are going to have 3 tracks to set the in's and outs on.
Track 1 - original source [audio track]
Track 2 - Compression Return [aux track]
Track 3 - Track we are recording the original source compressed to [audio track]
On track one set the output to the compression send output (or whatever name/output you want to use). We aren't inputing anything to this track so it can be set to none.
On track 2 Set the input to "compression return" or which ever one you used to bring the signal back into the 001. I.E What is the output of the RNC plugged into on your 001?
On track 2 set the output to a bus lets call this bus 4 for the sake of what we are doing.
On track 3 set the input the bus 4 (it could be any bus)
On track 3 set the output to your main outs.
So the signal flow will be
Track 1 - original source [audio track] > Digi 001 output 3 > Input 1 RNC > Output 1 RNC > Digi 001 Input 4 > Track 2 INPUT- Compression Return [aux track] > Track 2 OUTPUT- Bus 4 [aux track] > Track 3 INPUT Bus 4 > Track 3 OUTPUT (speakers, main out etc)
Ok now, I think you can do this without the Aux track, but i'm at work and wrote that from memory, so if anyone wants to correct it please do so, otherwise I will double check when I get home.