A processing apparatus includes a carrier receiving region configured to receive a sample carrier with at least one channel that carries at least one sample. The apparatus further includes a thermal control device configured to thermal cycle the sample carrier when the sample carrier is installed in the carrier receiving region, thereby thermal cycling the sample carried therein. The apparatus further includes a thermal control system configured to control the temperature control device based on a predetermined set of target sample temperatures and a temperature map, which maps the predetermined set of target sample temperatures to a set of temperatures of the temperature control device. The set of temperatures of the temperature control device is different from the predetermined set of target sample temperatures, and the set of temperatures of the temperature control device thermal cycle the sample carrier with the temperatures of the predetermined set of target sample temperatures.