24 line outputs using three interfaces (UR824 as main)

I think I have already found the answer to my question in another thread, but I don’t have a third interface to hook up and actually test my theory. Anyways, I’m going to describe my situation:

Right now I have my UR824 connected to my computer via USB and it’s selected as my default playback device (Windows audio preferences) and is selected as my master interface in Cubase via the Yamaha Steinberg USB Asio driver. I am running 8 channels of 44.1khz to my Profire 2626 (slave) which is connected via ADAT A (there are no other connections other than power). These 8 channels of audio are exiting the Profire 2626 via the 8 line outputs. This gives me 16 simultaneous line outputs.

I can setup the UR824 mix software accordingly and everything works as I would expect.

I’m looking to add another 8 channels of 44.1khz line outputs so that I can have 24 simultaneous line outputs. Is this possible? I would guess that it is possible, given Norbury Brook’s response and given the description that Steinberg gives of the UR824 as being able to handle 24 channels of simultaneous I/O.

However, when I try to configure the second set of ADAT outputs (ADAT B) in the mix control software, I am only able to select from DAW Out 1 through 16. I’m already using all 16 DAW Outs with my UR824 and Profire 2626.

Why isn’t there an option to select DAW Outs 17 through 24? The only other available options are Mix 1 through 4 and Analog In 1 through 8. Is this really the only options? The interface is advertised at having 24 simultaneous outputs. Am I just completely missing something here? Or do I actually have to connect a third interface (slave) and then the software will recognize this and allow me to select DAW Outs 17 through 24, but only after successfully connecting this third interface via ADAT proper?

Here’s something visual:
UR824.jpeg

I do something similar. I have mine setup so that the analog outs are Mix 1-4 and ADAT outs are DAW 1-16. If you want the Mix outs to act as simple line outs, then go into the appropriate mixer and mute everything except the DAW input.

Hmm, I’m not sure how having only DAW input is going to give me 8 more line outputs. Isn’t that just simply choosing my analog inputs to be routed out via the Mix 1 through 4? Basically directly monitoring the inputs?

But either way, I’ve decided to stick with three interfaces, using my UR824 outputs as Mix 1-4, Saffire Pro 40 outputs as DAW 1-8 (ADAT A), and Profire 2626 outputs as DAW 9-16 (ADAT B). Having Mix 1-4 helps me for recording, while the DAW 1-16 is used for mixing, so I guess I’m not too worried about having these limits.

Mix 1 through 4 (L+R) using only DAW inputs = 8 outputs
ADAT A = 8 outputs
ADAT B = 8 outputs
TOTAL = 24 outputs