Patent ID: 8896820

Claim:
A base module for an optical measurement instrument, the base module comprising: a mechanical structure for forming a measurement chamber and for supporting one or more optical measurement elements, a reception device inside the measurement chamber for receiving samples to be measured, heating resistors placed at different places of the measurement chamber, each heating resistor being arranged to warm the measurement chamber, at least one temperature sensor, each temperature sensor being arranged to produce a temperature signal responsive to temperature of the measurement chamber, and a controller arranged to control electrical power supplied to each of the at least one heating resistor on the basis of the at least one temperature signal produced by the at least one temperature sensor, wherein the controller is arranged to control the electrical powers supplied to the heating resistors so that the electrical power supplied to a first one of the heating resistors is proportional to B 1 ×q and the electrical power supplied to a second one of the heating resistors is proportional to B 2 ×q, wherein q is a quantity controlled on the basis of one of the at least one temperature signal, B 1 is a pre-determined balancing coefficient specific to the first one of the heating resistors, and B 2 is a pre-determined balancing coefficient specific to the second one of the heating resistors, the balancing coefficient B 1 having a different value than the balancing coefficient B 2 in order to compensate effect of differences in temperature/power-characteristics related to surroundings of the first and second ones of the heating resistors.