TROUBLE DIAGNOSIS UNIT FOR PROGRAMMABLE CONTROLLER

摘要

PURPOSE:To avoid such a case where a trouble diagnosis program is produced by a user himself by attaining the changeover between a teaching mode and a diagnosis mode and at the same time providing a teaching operation control means and a diagnosing operation control means. CONSTITUTION:A trouble diagnosis unit 4 performs the teaching or diagnosing control in accordance with a teaching mode or a diagnosis mode. In a teaching control mode, an input/output pattern and the time elapsed from the changing time point preceding by a step are stored successively in a storage part 42 every time an output pattern changes. In a diagnosis control mode the diagnosis is carried out based on the input/output pattern and the time elapsed stored in the part 42. In other words, a trouble state is decided if no coincidence is obtained between the present output pattern and a reference output pattern within a reference priod of time. Then the discordant area between both patterns is delivered as a trouble related area.