The stability of mobile cranes depends, among other things, on the extent to which the outrigger cylinders can be extended depending on the space available. In order to calculate the maximum permissible load depending on the support situation, it must be known how far the individual outrigger cylinders have been extended. WEBER-HYDRAULIK has developed a redundant position measuring system with an optical sensor for this purpose. An absolute binary laser code applied to the piston rod is monitored by a sensor that determines the current position of the piston rod. Due to its installation in the cylinder design, the position measurement system is particularly safe from external environmental influences.