The rack-based I/O system consists of a central rack and one or two 19 inch expansion racks intended for double size Euro boards. Each rack is equipped with a power supply unit PSF. ... The rack-based system is intended for industrial use and meets the EMC directive 89/336/EEC and the Low Voltage Directive, LVD, 73/23/EEG (Google source)
If this is it ...I think I struggle regardless, sadly