设置一个二级Matlab s函数块采样时间到特定的时间间隔

Matlab beginner here and I'm stuck on some problem and neither Matlab documentation nor other posts here could help me. I'm working on a Level-2 Matlab S-Function that receives a sensor signal via USB (Gyroscope, Magnetometer and Accelerator signals) and I have to analyze this data every 200ms for more high level tasks. At first I thought I can just set the simulation time of Simulink model to Start time 0 and Stop time 10 and make set my blocks sample time at 0.2 through block.SampleTimes = [0.2 0]; but then after getting some unexpected behavior I found out that through the documentation that simulation time is not the same as clok time in Simulink:Matlab beginner here and I'm stuck on some prob