This is clearly a Division by zero error as shown in the Diagnostic viewer. To know which block is causing this error, go to Configuration parameters>Diagnostics>Data Validity and set Inf or NaN block outputto error and run the model.
You will get the error as follows:
An error occurred while running the simulation and the simulation was terminated.
Caused by:
- Block 'BlockName' outputs 'NaN' for element x of output port x at major time step 0
where BlockName is the block which caused this error.
After identifying the block, further debugging can be done to ensure that zero is not passed to the denominator of a division block. This helps prevent `Inf` or `NaN` values from being fed into the integrator.