A fluid-flow measuring ball valve includes a replaceable ball within a housing. An adaptor is fed with measured values of matter properties and measured values of controlled and uncontrolled outputs, to adapt the simulation model accordingly. The measured system operating parameters can include the load of the compressor and the pressure and temperature of refrigerant in the flash tank. The lens unit includes an electrically-controlled zoom lens disposed above the light-emitting element and retained by the support element. A pattern is formed employing the semitransparent phase shifting mask.