The present invention relates to a system and to a method of controlling a fluid pump, as well as to a linear compressor and a cooler provided with means to calibrate the respective functioning at the time of the first use or in cases of problems caused by electric or mechanical failures. According to the teachings of the present invention, the fluid pump is provided with a piston-position sensing assembly, the electronic controller monitoring the piston displacement within the respective cylinder by detecting an impact signal. The impact signal is transmitted by the sensing assembly upon occurrence of a impact of the piston with the stroke end, the electronic controller successively incrementing the piston displacement stroke upon a trigger signal as far as the occurrence of the impact to store a maximum value of piston displacement.