Initialize logic block simulink

Hi I have implemented a set/rest D type flip flop in simulink. But am getting the following error "Cannot solve algebraic loop involving 'Set_Reset_D_Flip_Flop/Logical Operator3' because it consists of blocks that cannot be assigned algebraic variables" I'm pretty sure the error is occurring as some inputs depends on outputs of other blocks. Is there a way to set initial conditions on logic blocks in simulink?

Answer 1

[Fangjun Jiang]

1. There is no "initial condition" in a Simulink Logical Operator block. The output is solely dependent on the input/inputs.
2. By definition, there is no "initial condition" or state in a D Flip-Flop.
3. To be able to set an "initial condition" or initial state, you have to have a "memory". The "Initial Condition" block, or the "Memory" block, or the "Unit Delay" block can be used.
4. The "D Flip-Flop" block is available in Simulink library, "Simulink Extras"->"Flip Flops"