The development and implementation of a prototype to improve the current maintenance procedure applied to the SIS, Safety Instrumented System, of the raw materials and products conveyor belts of the Coke Plant operational unit of CST are reported. Due to the continuous mode of operation, currently protection switches can only be inspected visually, which does not ensure a perfect operation. The aim of this new tool is to allow the online inspection and testing of the safety switches without interfering with the production and to maintain its functionalities.