To solve the problems occurred during the application of fieldbus in thermal power units

the technical schemes about fieldbus online monitoring and intelligent diagnosis are proposed. On this basis

an intelligent bus diagnostic instrument is designed and developed. This instrument can monitor and record bus frames in real time. The recorded frames are then computed

checked and classified to generate the diagnosis data of running state of the master and slave device. The actual test and application data show that

this intelligent bus diagnostic instrument can monitor each slave station equipment in real time

analyze and compute the bus running status dynamically

and provide a basis for fieldbus diagnosis and problem analysis.