Thread Subject: linearising simscape model ?

hi,

i have created a non linear model of a thermal lumped mass system using simscape blocks with simulink signals defined as input and outputs. I want to get the state space representation of such a system for which I am trying to linearise using the "Simulink Control Deisgn"toolbox. However the command 'linearize' does not give me proper results. my b, c and d matrices are all zero matrices.

Any ideas on what could be the issue ? Its a vague question, but any ideas regarding this system might help.
Also, in the thermal blocks I have on custom built block with non linear functions that represents a peltier element. Can this be an issue, using custom built blocks ?

Regards,
Dipan