题目内容

下列对PLC输入继电器的描述正确的是（）。

A. 其线圈只能由外部信号来驱动
B. 其线圈只能由程序来驱动
C. 输入继电器的线圈既可以由外部信号来驱动又可以由程序来驱动
D. 以上说法都不对

查看答案

搜索结果不匹配？点我反馈

更多问题

The author of this essay was an English tourist.

A. 对
B. 错

The idea of linking the British Isles with Europe started in the early 20th century.

A. 对
B. 错

The Chunnel will facilitate the transport between Great Britain and other European countries.

A. 对
B. 错

The Chunnel project was carried out in a uniform way on both British and French sides.

A. 对
B. 错