A method for controlling a position of a target point on a processing result relative to a focus point of a focusing sensor system for determining properties of the processing result which is located inside a cartridge, and where the focusing sensor system is stationary at a set position relative to a disc rotatable about a first axis by a first motor connected to a controller, and where the cartridge is rotatable about a second axis by a second motor connected to a controller, and where the cartridge is smaller than the disc and placed in and off-centre of the disc, comprising the following steps: a) defining a point within the cartridge as an initial focus point of the focusing sensor system, where the initial focus point is a point (r, θ), where r is a fraction of the radii of the cartridge, and θ is the angle between a first reference point on the cartridge and the initial focus point; b) controlling rotation of the cartridge and disc such that the focus point of the focusing sensor system corresponds to the initial focus point, by determining angular positions φ and Θ to be set for the cartridge and the disc such that the initial focus point of the focusing sensor system corresponds to the point (r, θ) within the cartridge, where angle Θ of the cartridge is determined relative to the first reference point on the cartridge, and angle φ of the disc is determined relative to a second reference point on the disc, characterized in c) checking whether the initial focus point of the focusing sensor system corresponds to the target point on the processing result by capturing images of the processing result in the cartridge and the initial focus point within the cartridge, and comparing (x, y) target positions in captured images with the initial focus point of the focusing sensor system, and adjusting rotation of the cartridge and disc such that the focus point of the focusing sensor system corresponds to the target point on the processing result, and d) detecting and examining signals received from the focusing sensor system for determining properties of the processing result at the target point wherein an area of the processing result is scanned by rotating the disc and cartridge to angles φ and Θ such that the focusing sensor system focus on a point (r, θ) within the cartridge corresponding to the target point and properties of the processing result are iteratively detected by turning disc and cartridge in steps for covering the area. a) defining a point within the cartridge as an initial focus point of the focusing sensor system, where the initial focus point is a point (r, θ), where r is a fraction of the radii of the cartridge, and θ is the angle between a first reference point on the cartridge and the initial focus point; b) controlling rotation of the cartridge and disc such that the focus point of the focusing sensor system corresponds to the initial focus point, by determining angular positions φ and Θ to be set for the cartridge and the disc such that the initial focus point of the focusing sensor system corresponds to the point (r, θ) within the cartridge, where angle Θ of the cartridge is determined relative to the first reference point on the cartridge, and angle φ of the disc is determined relative to a second reference point on the disc, characterized in c) checking whether the initial focus point of the focusing sensor system corresponds to the target point on the processing result by capturing images of the processing result in the cartridge and the initial focus point within the cartridge, and comparing (x, y) target positions in captured images with the initial focus point of the focusing sensor system, and adjusting rotation of the cartridge and disc such that the focus point of the focusing sensor system corresponds to the target point on the processing result, and d) detecting and examining signals received from the focusing sensor system for determining properties of the processing result at the target point wherein an area of the processing result is scanned by rotating the disc and cartridge to angles φ and Θ such that the focusing sensor system focus on a point (r, θ) within the cartridge corresponding to the target point and properties of the processing result are iteratively detected by turning disc and cartridge in steps for covering the area.