为了保证PLC交流电梯安全运行,()电器元件必须采用常闭触点,输入到PLC的输入接口。
A、停止按钮
B、厅外呼梯按钮
C、轿厢指令按钮
D、终端限位行程开关
参考答案:D
---I really like the record you lent me last week.
---____.
---And thank you very much for letting me keep it so long.
A.I’m glad you like it
B.That’s all right
C.Don’t mention it
D.I hope you like it
吊装作业前应对吊装点进行识别如果识别不到位会产生哪些危害因素和后果?