Pump modeling with characteristic curves or kennlinien,

Hello everybody at matlab.

                               I have a question, i don't have enough knowledge of Matlab/simulink. I have to design a model of a Pump(in simulink most probably)

i don't know the Resistance,Conductance, impedance ,inductance values .... the Pump is WP29 which i got from company.

I have to model it on the basis of its INPUT and OUTPUT curves

which are also called PErformance curves of a Pump.

can somebody tell me would it be possible to write the differential equations and then make a PUMP MODEL ? if you need more information about the PUMP please ask.

And i only want to make an equation, i don't want to use the following function.

http://www.mathworks.de/de/help/physmod/hydro/ref/centrifugalpump.html as it has limitations.

is there a way/Matlab function to find the unknown parameters of a system with known INPUTS and OUTPUTS ?