1. A method of monitoring the performance of a plant including devices, control loops and equipment comprising: a. performing diagnostics from a device level, to a control loop level and then to an equipment level; b. converting results of the diagnostics of each of said levels into respective Key Performance Indicators (KPIs); c. comparing said KPIs with predetermined operating benchmarks for each of the said devices, control loops and equipment; d. determining, using a comparator, performance levels of each of said devices, loops and equipment based on said comparing; and e. displaying the performance level as only three levels of performance.