A process data management system (1) has a number of modules (2 6) each of which can operate independently to capture, process, and record process data from machines (P1 P6). The modules also communicate with each other via a messaging service (21, 40) so that data can be routed between components (22 24, 42, 43, 45) of different modules using the Push mechanism. A Graphical data object (GDO) server (25, 45, 46) downloads applet instances to user browsers in response to the browser addressing a URL. The applet generates an output display in chart form of real time processed data.