This applies to the Legacy Saffire Interfaces (Saffire, Saffire LE, Saffire Pro 10, Saffire Pro 26 I/O)
There are two choices for using the Saffire pro in standalone mode.
Tracking Mode will route the analogue inputs to the ADAT outputs, and the ADAT inputs to the analogue outputs.
Mixer Mode will leave the Saffire set up exactly as it was when disconnecting from the computer.
In both cases, make sure that you've selected the sampling rate that you want to work at.