Bombardier Aerospace in Belfast, Northern Ireland, specializes in designing and manufacturing large aircraft parts, including fuselages, wings, engine nacelles and flight control surfaces. They use riveting and drilling machines by BRÖTJE-Automation at the production site based on PROFIBUS DP communications. A master system controls the riveting and drilling equipment and the lifting, lowering and swiveling of the components.
In spring 2011 one PROFIBUS network started failing sporadically.
To find the reason, BRÖTJE-Automation carried out measurements using the PB-INspektor tool and detected that one node was disturbing the system. The node could not be identified, however, and therefore an Indu-Sol instrument specialist was called for further investigation. The initial physical measurement showed no fault and a test by the line tester gave no clue as whether there was any faulty cabling. Finally one of the failures was recorded by the PB-INspektor and an analysis of the snapshot (pictured) confirmed that the "disturber" was a reader whose printed circuit board had heated up excessively causing the reader to scorch. The device was replaced and the bus checked again to make sure that no other device was causing trouble and no other defects were occurring. Since then the plant has run properly without any failure.
By using the appropriate test tool and based on respective technical experience even a quite sporadically failure in a PROFIBUS network could be identified.
And not PROFIBUS failed, but simply a PCB of a reader!