C="Zintbr (Backwards Rectangular Digital Integrator) Model:
Models the equation: y(k) = y(k-1) + dt*x(k) where y(k) is the output, x(k) is the input, and dt is the digital update time. The digital update time is set by the user in seconds. This approximation is often used in digital control applications and will become unstable for large values of dt. Note the external override of the pulse train block to externalize the time between samples parameter.
Limitations:
1. Digital Update Time, sec >0 and >simulation stepsize"