how to make the constant block pick up parameter values from a 'clickfcn' annotation??

On running the simulink model attached herewith, I get the error "Error evaluating parameter 'Value' in 'quadruple_tank_interacting_oloop/4tanksystem/Constant1'. Undefined function or variable 'g'".I want the constant blocks to pick up their respective parameter values from the clickfcn annotation that I have used. How do I modify the constant blocks to pick up the values of a11,a22, g etc from the annotation block...?? Please help me with this....