| Summary: | 碩士 === 國立屏東科技大學 === 食品科學系 === 90 === The sterilization of the canned food is a crucial operation for the canning. The criterions in sterilization are temperature and time. In this study, a PLC-based fuzzy controller was designed for decreasing temperature error. The result showed that it could reduce its error within ± 0.4℃ and sterilization time would be adjusted determined by sterilization value (F0 value). In order to avoid over sterilization on the canned food, grey prediction method was proposed to predict proper F0 value to end the sterilization. The calculation of F0 value had been coded into the ladder diagram of PLC, in the way of lookup table. The result showed that using fuzzy temperature control could obtain the better sterilization quality. By statistical analysis, there is no significant difference for the calculated results both obtained from PLC on-line and PC off-line. Accordingly, the function of small size PLC has been enhanced not only for its control precision but also for improving sterilization process. Meanwhile the communication protocol between PLC and PC and intranet between PLCs were constructed, and displayed on website by associating with network camera to monitor the whole process.
Key words： PLC、 Fuzzy control、F0 value、Grey prediction
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