Abstract: The invention is related to a system of identification of the location of a matrix-like sample tray on a plane (2) in an equipment for the treatment of the samples. The sample tray is placed in a frame having an L-shaped electrically conductive piece (8). The equipment for the treatment comprises a number, corresponding to the number of vertical lines of the tray, electrically conductive strips (9), a number, corresponding to the number of horizontal lines, electrically conductive strips (10), and means for transmitting an electric signal to the strips of the vertical line and for receiving from the strips of the horizontal lines.