【多选题】关于S7-200系列PLC计数器,下列说法中正确的有:( )
A.
计数器 C 都具有断电保持功能, PLC 断电后计数器当前值保持不变。
B.
计数器 C 都具有驱动信号断开后当前值保持不变的保持功能。
C.
S7-200 系列 PLC 内计数器是无限的,想用多少有多少。
D.
计数器是用以记录脉冲信号个数的内部器件,利用输入脉冲上升沿累计脉冲个数。
【简答题】I once experienced an unforgettable trip to Gloucester to see some of the world’s most beautiful and exciting animals in their own habitat(栖息地), the North Atlantic Ocean. After a long trip by bus, we ...
【简答题】(服务员)点菜 take the ____________
【多选题】对于S7-200系列PLC的计数器,下列说法正确的是
C.
对于加计数器,CU端有上升沿输入时,计数器当前值加1
【单选题】The waiter seems to be in a hurry to take our order.
【简答题】火眼金睛,选出合适的答案。 1. 当服务员问你:“您准备点菜吗?”可以说: [ ] A. What is it? B. Are you ready to order? 2. “我买两个热狗。”可以说: [ ] A. I'll take two hot dogs, please. B. Two yuan. 3. “橡皮多少钱?”可以说: [ ] A. How much is ...
【判断题】After whale watching from boats or shore, a few companies are now offering the possibility of actually swimming with whales in the wild.
【单选题】Section B Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you ...
A.
By research with commercial whale watching tour.
B.
By research with navy marine.
C.
By research with whaling hunting.
D.
By research with local fishermen.