If you have some system in a superposition of states, then when your measuring gadget interacts with it it becomes entangled with the original system and it too is in a superposition of states. If you walk over to look at your measuring gadget you too become entangled and enter a superposition of states, and so on up to and including the journal you publish the results in.
In real life we don't see macroscopic objects, cats or otherwise, in a superposition of states, and the reason is generally considered to be decoherence. The describes the interaction of a system with the rest of the universe and the loss of coherence that results. The rate at which a system decoheres increases with the complexity of the system, so while a superposition of states can be maintained for an atom or molecule, it is lost almost instantaneously for something the size and complexity of lab equipment, and your experiment returns a definite value for whatever you were looking at.
The largest system that has been observed in a superposition of states contains about ten trillion atoms.