# 2.3.2 類比輸出

本產品亦內建一組4-20mA 類比電流輸出訊號，提供做量測值的類比輸出，相關使用事項如下： 

● 可以選擇流量、流速、上游溫度、下游溫度流體聲速、上下游溫度差等輸出。 

● 可自訂上下限。提供所需要的輸出範圍。 

● 本4-20mA 為無源訊號，需要外部電源輸入才罷驅動，請注意此電源必須為另一組獨立電源不能共用儀表電源否則會造成燒機的可能！接線時請依照標示的正負符號給電，外部電源的電壓範圍可以是2-30VDC，建議使用12V，較高的電壓可能帶來儀表的溫度上升。


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