| 摘要 |
PROBLEM TO BE SOLVED: To provide a process input/output unit having high reliability, maintainability and visibility, with the reduction of wiring manpower, incorrect wiring and inspection manpower. SOLUTION: In place of the conventional relay circuit, a processing input/output unit 3, etc. are realized by a microprocessor 301 and software. The software is stored in nonvolatile rewritable memory devices 302. The software is rewritable by means of a maintenance supervision unit 6. Further, by setting a limit value for the number of rewriting times, rewriting is inhibited when exceeding the above number of rewriting times. Also, to prevent rewriting by mistake, a rewrite permission/non-permission switch is provided. COPYRIGHT: (C)2007,JPO&INPIT
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