HART375里面这几段话的含义

学习自控仪表

看到王天泽在现场仪表版说的HART375的极性问题，但是都是英文，看不懂啊。原文：手持终端的两根通讯线有极性吗
Connect the 375 Field Communicator with the appropriate connectors in parallel with the instrument or load resistor. The HART connections are not polarity sensitive.
In order for the 375 Field Communicator to function properly, a minimum of 250 ohms resistance must be present in the HART loop. There are three terminals on the top of the 375 Field Communicator.
Two of them are red and one of them is black. Each red terminal is a positive connection for its protocol. The black terminal is a common shared by both protocols. There is an access door to ensure that only one pair of terminals is exposed at any one time; see Figure 3-1. There are several markings to indicate which pair of terminals is for which protocol.

舞长安

Connect the 375 Field Communicator with the appropriate connectors in parallel with the instrument or load resistor. The HART connections are not polarity sensitive.
使用适当的连接器将375现场通讯器与仪器或负载电阻并联。 HART连接不对极性敏感。
In order for the 375 Field Communicator to function properly, a minimum of 250 ohms resistance must be present in the HART loop. There are three terminals on the top of the 375 Field Communicator.
为了使375现场通讯器正常工作，HART回路中必须至少存在250欧姆的电阻。 375现场通讯器顶部有三个端子。
Two of them are red and one of them is black. Each red terminal is a positive connection for its protocol. The black terminal is a common shared by both protocols. There is an access door to ensure that only one pair of terminals is exposed at any one time; see Figure 3-1. There are several markings to indicate which pair of terminals is for which protocol.
其中两个是红色的，其中一个是黑色的。 每个红色端子是其协议的正连接。 黑色终端是两种协议共享的。 有一个检修门，以确保只有一对端子在任何时间暴露; 参见图3-1。 有几个标记来指示哪一对终端是哪个协议。

gubai0348

将375与仪表并接，HART协议对极性无要求，为了通讯正常，请确保HART回路至少有250欧姆电阻。375的顶端有3个接线端，2红1黑。每一个红色都是它的协议的正极，黑色是公共端。但每次只能由一个协议可用，如图3-1，有几个标识表明哪对端子对应哪个协议。

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