PURPOSE: To automatically group output signals which can be diagnosed independently of one another as to a fault from the view point of the ladder program of a programmable logic controller(PLC).
CONSTITUTION: An output coil to be monitored is selected (step 101). A list of input/output contacts (including internal auxiliary contacts) that respective output coils refers to in the ladder program is generated (step 104). The degree of connection between two optional output coils is calculated on the basis of whether or not there are input/output contacts to be referred to in common or their number and output coils in subordinate relation are extracted (step 106). Those connection extent calculation and subordinate relation extraction processing are carried out for all selected output coils. The output signals are grouped so that mutually relative output coils are in the same group by referring to the degree of connection and the subordinate relation.
NISHIDAI HAJIME
IRIE ATSUSHI
SOMA KOJI
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