Ina whakamahia mō ngā tono aroturuki ahumahi, ka taea e ngā pūoko te tuhi i ngā āhuatanga o te āhuarangi. Ka whakamahia ngā tohu pūoko i roto i te tukanga hei aroturuki tonu i ngā huringa ki te rohe e aroturukitia ana. Ka taea te puta ngā tohu matihiko me ngā tohu anaro.
I te nuinga o te wā ka puta he ngaohiko hiko, he iahiko rānei e rite ana ki ngā taurangi ā-tinana e aro turukihia ana.
E hiahiatia ana te tukatuka tohu anarau ina me pupuri tonu, me eke rānei ngā tukanga aunoa ki ngā āhuatanga kua tautuhia. He mea nui tēnei mō ngā tono aunoatanga tukanga. Ko ngā tohu hiko paerewa te tikanga e whakamahia ana mō te hangarau tukanga. Kua whakapūmautia ngā au / ngaohiko paerewa anarau 0(4)...20 mA/ 0...10 V hei taurangi ine me te whakahaere ā-tinana.