【正文】 還比較高，因此應(yīng)該合理選用 PLC 的 I／ O 點的數(shù)量，在滿足控制要求的前提下力爭使用的 I／ O 點最少，但必須留有一定的裕量。在工藝過程比較固定、環(huán)境條件較好（維修量較?。┑膱龊?，建議選用整體式結(jié)構(gòu)的 PLC；其它情況則最好選用模塊式結(jié)構(gòu)的 PLC。當(dāng) PLC 處于停止模式時，只執(zhí)行以上兩種的操作。接著進(jìn)入程序執(zhí)行階段。 2）設(shè)置一個系統(tǒng)清除和搶答 控制開關(guān) REST/START，該開關(guān)由主持人控制?？梢哉f ,到目前為止尚無任何一種工業(yè)控制系統(tǒng)的可靠性能達(dá)到和超過 PC。 焦作大學(xué)機電工程學(xué)院畢業(yè)設(shè)計 目錄 目 錄 1 緒論 ........................................................................................................................... 1 PLC的認(rèn)識 ....................................................................................................... 1 PLC的應(yīng)用和特點 ............................................................................................. 1 2 設(shè)計目的及要求 .......................................................................................................... 2 設(shè)計目的 .......................................................................................................... 2 基本要求 .......................................................................................................... 2 3 硬件電路設(shè)計 ............................................................................................................. 3 PLC工作原理 ..................................................................................................... 3 PLC機型選擇步驟與原則 .................................................................................. 5 PLC的容量包括 I／ O點數(shù)和用戶存儲容量兩個方面 .......................................... 7 控制要求分析 ..................................................................................................... 7 搶答電路分析 ..................................................................................................... 7 程序流程圖 ........................................................................................................ 9 4 軟件設(shè)計 .................................................................................................................... 10 I/O分配表 ....................................................................................................... 10 ............................................................................11 5 仿真與調(diào)試 ............................................................................................................... 21 仿真軟件 GX ............................................................ 21 系統(tǒng)的仿真 ...................................................................................................... 21 工作過程分析 ................................................................................................... 22 致謝 ............................................................................................................................... 23 附錄 ............................................................................................................................... 24 參考文獻(xiàn) ........................................................................................................................ 25 焦作大學(xué)機電工程學(xué)院畢業(yè)設(shè)計 第 1 章 緒論 1 1 緒論 PLC 的認(rèn)識 PLC 是專為在工業(yè)環(huán)境下應(yīng)用而設(shè)計的一種數(shù)字運算操作的電子裝置 ,是帶有存儲器 ,可以編制程序的控制器。 關(guān)鍵詞 搶答器；可編程控制器； 焦作大學(xué)機電工程學(xué)院畢業(yè)設(shè)計 摘要 ABSTRACT PLC application field has been broaden from various fields, in daily life, intelligent vies to answer first device widely used in various petitions and vies to answer first occasion. Due to the PLC system responder relative stability, so imagine can use PLC for the design of the responder. Before start vies to answer first, the first through the reset button realize circuit reset, the questions later, open the selector switch start timer. In vies to answer first time, when a group of preemptive press vies to answer first button, the corresponding auxiliary relay on, at the same time cut off other vies to answer first circ