Patent Document ID: 8060221
Application ID: 12304632
Patent Flag: 1

Claim One:
1. A programmable-logic-controller peripheral device that is connected to a programmable logic controller, which controls an external apparatus based on a sequence program, and verifies an operation state of the sequence program in the programmable logic controller, the Programmable-logic-controller peripheral device comprising: a tracing-result optimization processing unit that generates an optimized tracing result obtained by correcting, based on performance of the external apparatus, a tracing result obtained by the programmable logic controller executing sequence processing corresponding to a predetermined signal input/output unit out of external apparatuses; a tracing-result collation processing unit that collates the optimized tracing result and a time chart as a basis of the sequence processing for the external apparatus and detects shift of the optimized tracing result; and a tracing-result storing unit that accumulates and stores therein a tracing result obtained by the programmable logic controller executing, at predetermined time intervals, the sequence processing for the predetermined signal input/output unit out of the external apparatuses, wherein every time the tracing result is stored in the tracing-result storing unit, the tracing-result optimization processing unit generates the optimized tracing result, and the tracing-result collation processing unit has a function of performing collation of the optimized tracing result and the time chart and detecting shift of timing due to elapse of time.