Limitation on Dwork numbers for S-function

Hi, guys,

I'm trying to apply a S-function, M-file, Level 2 for composing my own Kalman filter, in which there are some matrix i have to conserve for the calculation in the next cycle. Matlab version: 2015b

Since the Kalman filtering is a discrete system, thus i'm using Dwork to store the desired matrix through breaking the matrix into multiple vectors. However, the simulink system indicates that the number of Dwork can only be as many as 6: Caused by: Invalid Dwork index for 'learning_2/Level-2 MATLAB S-Function1'. Dwork index must be in the range from 1 through 6

Is there any chance i can customize this rule? Or any advice that i can store my matrix variable for the calculation in the next cycle?

Bruno Liu