Exponential Degradation model in simulink

I want to implement an "exponentialDegradationModel" in simulink. Basically I want to use simulink to read in each step a value from a sensor and update with this value the "exponentialDegradationModel" so to estimate RUL in every step. In Matlab environment is quite straight forward:

update(mdl,newValue); %mdl is the exponentialDegradationModel and newValue the value I use to update.

But when I do the same in Simulink using mdl and a newValue as input of the function block I get thefollowing error:

"Unsupported input format for From Workspace block 'RemainingLife/mdl'. Available formats are double non-complex matrix, a structure with or without time, or a structure with MATLAB timeseries as leaf nodes. All formats require the data to be finite (not Inf or NaN)".

I am reading mdl and newValue from workspace.