There are provided a band-shaped tray 12 having grasping grooves 12a for grasping opposite side ends of wafers 1, and a cleaning tank 20 to which the wafers 1 inserted in the tray 12 are conveyed by a conveyor robot 2 to be cleaned. The devices are operatively coupled to a host device running a host application and the analyser is adapted to be housed in an enclosure which, in use, houses at least one of the devices. The PWM driver provides a series of fan drive pulses on the output terminal, and the limiter prevents the voltage on the output terminal from falling below a predetermined voltage. The invention is distinguished in that its operation does not require knowledge of either the transmitted power or antenna gain of the intruding signal source. Optical interference signals of the reference beam and the signal beam penetrating the medium are respectively detected and converted into heterodyne interference electrical signals. When the diagnostic tool recommends and executes a data intensive application as the further diagnostic tool, it automatically configures a controller of the process control network to collect the data needed for such a tool.