Sorter performance monitoring method and system

A method of sorting articles with a sorter apparatus and a sorter apparatus having a conveying surface that is adapted to transport articles in a direction of conveyance and a mechanism adapted to displace articles on the conveying surface, the sorter apparatus having an endless web of bodies travelling in an endless loop defining the conveying surface includes a distributed drive system having at least one drive that is adapted to produce to provide force with at least one of the bodies to propel the endless web. A diagnostic device traveling with the web and positioned at one of the bodies of the endless web. The diagnostic device is adapted to monitor operation of the sorter apparatus and includes at least one sensor that is adapted to detect at least one parameter of a proximate drive that is proximate to the at least one sensor, and a controller adapted to receive the at least one parameter from the at least one sensor. A stationary thermal sensor may also monitor the endless loop via another controller including receiving thermal data from the stationary thermal sensor and the another controller correlates the thermal images with a portion of the endless loop.