The purpose of this bachelor thesis was to investigate the PLC systems used in ABBs breaker factory in Ludvika and to create a system specification suitable to be used in the procurement of a back-up solution for this workshop. This work involved information gathering from different sources, such as archives, physical installations and interviews of maintenance personnel and operators. The results included the requested system specification (in Swedish) including suggestions for pilot test installations and evaluations. The work also resulted in an extensive listing of all PLC systems with placement, typedesignations, expansion modules and other pertinent information. This information ismade available as a macro enabled multipage Microsoft Excel document. A summary and suggestions for follow up work is also included.