Patent ID: 8072889
Filing Date: 2011-12-06
Classification: G05B

Abstract:
1. A programmable controller wherein a plurality of external input devices and a processing device for processing an input signal group inputted from the external input devices are multiplexed by a plurality of systems and wherein upon coincidence between the input signal groups in all the systems, correct input signals are judged to have been inputted while upon non-coincidence therebetween, an abnormality stop processing is performed, wherein the processing device in one system comprises: diagnosis pulse output means for parallel outputting a diagnosis pulse group to the processing device in another system at a timing unique to the one system; check means for inputting thereinto diagnosis pulses outputted from the diagnosis pulse output means in the another system and for interrupting transmission of the input signal group for a period of the diagnosis pulses only; and abnormality judgment means for executing an abnormality stop processing when a signal of the input signal group changes in response to the outputting of the diagnosis pulses from the diagnosis pulse output means in its own system, wherein the signal processing device in the one system includes: serial diagnosis pulse output means for serially outputting serial diagnosis pulses for each input terminal to a processing device in another system; and pulse check means for inputting serial diagnosis pulses that are serially outputted for each input terminal from serial pulse output means of the processing device in the another system and for making the judgment of abnormality to execute the abnormality stop processing when an input signal does not change in correspondence to the period of the serial diagnosis pulses.