Linearnost vezja mora biti taka, da ne pride do nobene napake, večje od 0,001 °C na kateri koli točki razpona med - 0,400 °C to - 0,600 °C, če se instrument uporablja pravilno.
The linearity of the circuit shall be such that no error greater than p 0,001 oC is introduced at any point within the range -0,400 oC to -0,600 oC when the instrument is correctly operated.