用傳感器跟蹤工業過程

　　工業過程的成功在很大程度上是建立在穩定、可重復的條件下進行的。這有助于減少過程中的可變性，提高創建一致輸出的機會，并且使故障排除問題更加容易。

　　傳感器可用于建立測量、反饋和控制系統，以穩定工業過程的操作條件。但是你衡量什么呢？我們將研究一些與工業過程控制相關的基本傳感器類型，它們測量溫度、壓力、濕度、液位、氣體濃度和質量流量等因素。了解什么是傳感器，它們是如何工作的，以及它們的功能和局限性，有助于設計者創建監控系統，提供必要的精確信息，以確保工業過程的穩定性和可重復性。

　　Temperature

　　Tracking temperature is one of the most basic elements of process control. Although we are used to thermistors and temperature probes， other approaches are emerging to make it easier to gather multiple temperature readings from large installations.

　　Take Maxim’s DS18S20， a ‘1-wire’ digital thermometer， which only needs a single data line to communicate with a host controller. The part is available in a three-leaded TO-92 package， on which two of the leads are dedicated to power and ground and the third is the data output， and in an 8-pin Small Outline package with five unconnected leads. The thermometer can even draw its power from the data line， removing the need for a separate supply and simplifying installation.