A low-cost programmable timing controller for inspecting small components

In order to make electronic products such as personal digital assistants (PDA) and cellular phones be small and thin, their components must be also small and thin. Since it is very difficult to inspect these small components by human eyes, an automation system for inspecting them has been used. Compared with inspection systems for large or medium size components, those for small components need to be more precise. In particular, more precise timing for each action in the inspection system of small components is required. Programmable logic controllers (PLC) have been used for generating precise timing signals. However, it is neither convenient nor economical to generate timing signals by PLC. In this paper, a low-cost programmable timing controller to generate precise signals in the inspection system of small components is proposed and it is applied to an inspection system of multilayer chip capacitors (MLCC). Since the proposed controller is organized to have internal registers, counters, and software routines for generating timing signals, users do not have to program the details about timing signals and need not only send some values about an inspection system through an RS232C port. By selecting these values appropriate for a given inspection system, desired timing signals could be generated.