I have a Simulink xPC target application that has blocks with discrete states at several different sample rates and some sections using continuous states. My intention on keeping the continuous states is for better numerical integration. 

What creates the problem: One block is reading a device at a very fast rate (500 hz). The rest of the application can and should run at a slower rate (say, 25 or 50 Hz) because it would be overkill to run it at the highest rate, and because the processor simply cannot squeeze a full application cycle into the .002 secs of the faster rate. So I need both rates. However, the continuous states run by definition in Simulink at the faster discrete rate of the whole application! This means everywhere I have continuous states now they're forced to run at 500 Hz when 25 Hz would do!

Is there a way to force the continuous states in xPC target to a rate that is not the fastest in the application? Or alternatively, is there a way to allow certain block to run at a faster speed than the rest of the application?