问题描述：
求教英语24V DC control voltages,
DC control voltages,
grounded (earthed) and ground free.
grounded (earthed)是不是指24V-
ground free指24V+
直流控制24V怎么还分接地和不接地的呢 哪个是24V-吗
另外24V+怎么说
DC control voltages,
grounded (earthed) and ground free.
grounded (earthed)是不是指24V-
ground free指24V+
直流控制24V怎么还分接地和不接地的呢 哪个是24V-吗
另外24V+怎么说
问题解答：
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