How To Prevent Automatic Disarm?

I am currently working on an R&D project that involves a quadcopter. I need to be able to arm the motors and have them not spin, as well as to remain armed for several minutes. The automatic disarming feature on my quadcopter disarms it after 15 seconds of being armed, and that will not work for my project.

I know that there is an option for preventing the motors from spinning when it is armed, but is there one for keeping the motors armed for an extended period of time?

I am using an APM-mini 3.1.