常規狀態下，壓力變送器都是4-20mA電流輸出的，而4-20mA電流輸出的壓力變送器接線都是兩線制，但是還是有很多用戶不知道如何接線。下面昆山丹瑞先詳細說明下兩線制4-20mA電流信號輸出的壓力變送器接線，接線實物圖如下圖：  

打開壓力變送器后蓋，你會看到有四個壓力變送器接線端子，OUT正負和TEST正負，這里我們接OUT正負，TEST正負是廠家用來標定壓力變送器用的，現場使用就不用管著兩個端子的有什么作用，直接OUT正負就行。   

三線制接線實物圖如上圖所示，24V電源供電，24V＋接OUT正，24V－接OUT負。這樣，簡單的兩步即可完成壓力變送器接線，當然，市面上還有一些三線制的壓力變送器，那么三線制壓力變送器接線怎么接呢？ 三線制變換器的接線圖如圖 2 所示，電流輸出系統除了兩根電流傳輸線以外，還有一根電源線向變壓器提供電源。 三線制就是電源正端用一根線，信號輸出正端用一根線，電源負端和信號負端共用一根線。 其供電大多為 DC 24V ， 輸出信號有 DC4-20mA ，負載電阻為 250Ω 或者 DC0-10mA ，負載電阻為 0-1.5kΩ ；有的還有 mA 和 mV 信號，但負載電阻或輸入電阻，因輸出電路形式不同而數值有所不同。      

其實壓力變送器接線問題即便有客戶不懂，聯系昆山丹瑞廠家電話指導也非常簡單。現在設備無論變送器還是電子顯示儀還是其他閥門或者泵閥都是有接線端子圖或者直接兩個正負極端子，一目了然非常簡單。

Under normal conditions, pressure transmitters are 4-20 mA current output, and 4-20 mA current output pressure transmitter wiring is two-wire system, but there are still many users do not know how to wiring. The following Kunshan Than Shwe first details the connection of the pressure transmitter with 4-20mA current signal output from the next two-wire system, as follows:

Open the back cover of the pressure transmitter, you will see that there are four pressure transmitter terminals, OUT positive and negative and TEST positive and negative, here we connect OUT positive and negative, TEST positive and negative is used by the manufacturer to calibrate the pressure transmitter, site use does not need to care about the two terminals have any effect, direct OUT positive and negative on the line.

As shown above, 24V power supply, 24 V + OUT positive, 24 V to OUT negative. In this way, a simple two-step pressure transmitter connection can be completed, of course, there are also some three-limit pressure transmitters on the market, so how to connect the three-limit pressure transmitter connection? The wiring diagram of the three-wire converter is shown in Figure 2. In addition to two current transmission lines, the current output system has one power line to supply power to the transformer. The three-wire system is that the positive end of the power supply uses a wire, the positive end of the signal output uses a wire, and the negative end of the power supply and the negative end of the signal share a wire. Its power supply is mostly DC 24V, the output signal is DC4-20mA, the load resistance is 250_or DC0-10mA, the load resistance is 0-1.5k; Some also have mA and mV signals, but the load resistance or input resistance, due to the different form of the output circuit and the value is different.

In fact, pressure transmitter wiring problems even if customers do not understand, contact Kunshan Than Shwe manufacturer telephone guidance is very simple. Now the equipment, whether transmitter or electronic display or other valves or pump valves are wiring terminal diagram or direct two positive and negative terminals, at a glance is very simple.