How do you use the constant block as input to set the parameter value in the Cylinder block in simscape

I want to control the ‘stroke’ parameter value of the Cylinder in Injector1 in sh_diesel_injection model by the Constant block, and convert the whole model into a dynamic link library.

I set the stroke value through the Constant block and change the 'stroke' parameter value in the Cylinder block through the S-function. but it dosen't work.

set_param('sh_diesel_injection/Injector1/Cylinder','stroke', num2str(u(1)));   % 'test' S-Function

I get the following error:

Cannot change parameter 'Piston stroke (stroke)' of 'sh_diesel_injection/Injector1/Cylinder' while simulation is running.

How do I solve this problem? Somebody please help me in this regard.