Which section of a research paper is best to state that results also depend on equipment used?
I think it depends. In my opinion, it makes most sense to address equipment limitations (e.g. instrument resolution, reachable temperatures, etc.) in the method(ology) section, as was suggested by astronat. Limitations on your results, however, are more naturally addressed in the discussion (e.g. since we are resolution limited, we cannot definitively rule out alternative interpretations X, or Y, but our results are consistent with prevailing theory Z). If it is a particularly important qualifier that's central to your work, it can make sense to repeat it in the conclusion and possibly elsewhere.