S7-300的模塊機架（起物理支撐作用，無背板總線），西門子提供五種規(guī)格的導軌。
電源模塊（PS）
將市電電壓（AC120/230V）轉換為DC24V，為CPU和24V直流負載電路（信號模塊、傳感器、執(zhí)行器等）提供直流電源。輸出電流有2A、5A、10A三種
正常：綠色LED燈亮
過載：綠色LED燈閃
短路：綠色LED燈暗（電壓跌落，短路消失后自動恢復）

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3SE21001DV000AH3

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671740AA100AA0
67178H000AE0

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3RV10210KA10
3RV10210KA15
3RV10211AA10
3RV10211AA15
3RV10211BA10
3RV10211BA15
3RV10211CA10