Simulink random number blocks, as one would expect, output the exact same stream of numbers given the same seed. This becomes problematic if you have a large number of sensors and/or actuators, all with error represented as functions of random numbers. If you provide all random number generators with the same seed, all of your sensor errors will peak and trough in unison which is a pathalogical case. Conversely, if you seed random number generators with a random value, your sim is no longer repeatable.
The solution would seem to be to seed all of your blocks with a some global seed plus a value unique to each block. That way the sim is repeateable, all blocks provide "unique" random number streams, and you can easily vary the random number streams for monte carlo runs by simply varying the global seed value.
My question is, what is the best way to give each random number block its unique value. The brute force method of hand picking a number becomes tedious and difficult to keep track of pretty quickly. I forsee lots of complications here. For example, what do you do if you have a library block you use multiple instances of? Has anybody tackled this in a way they are happy with?