【判断题】
可编程控制器输入指令时，可以使用编程器来写入程序，所依据的是梯形图和指令表。可编程控制器的程序结束指令是END； stepping，代表步进。
查看试卷，进入试卷练习
微信扫一扫，开始刷题
相关试题
【判断题】
三相变压器的额定容量，是给一次绕组放额定电压时，为保证部温升不超过额定值所允许输出的最大视在功率。它等于二次绕组额定电压与额定电流 乘积的 √3 倍。
【判断题】
晶闸管触发电路的形式很多，但都由脉冲形成同步移相和脉冲移相几部分组成。
【判断题】
晶体三极管的输出特性是指基数电流为常数时Ic与Uc之间的关系。
【判断题】
电磁式断电器的释放电压（电流）值，取决于衔铁吸上后的最终间隙和弹簧压力。若增加非磁性垫片的厚度或增加弹簧压力，可以提高释放值，从而提高返回系数。
【判断题】
肖特基二极管的开关时间长，故开关损耗远小于普通二极管； 适用于电压不高，而又要求快速、高效的电路中，与普通整流二极管相比，反向恢复时间短，工作频率高。
【判断题】
变压器的主要部件有：铁芯、绕组、油箱、油枕、呼吸器、防爆管、散热器、绝缘套管、分接开关、气体继电器、温度计、净油器等。
【判断题】
在调校仪表时，数据的记录和数据的处理应遵循的基本原则是有效数字原则。
【判断题】
测量方法和理论引起的误差属于偶然误差。
【判断题】
仪表的精度不仅与绝对误差有关，还与仪表的绝对误差、测量范围有关。
【判断题】
表示仪表精度的相对百分误差、非线性误差、变差等都是指仪表在检测过程中达稳态后的误差，都属动态误差．
【判断题】
干扰线与套管之间以及套管与信号线之间存在分布电容，所以容易形成静电感应，不能接地，这种静电感应才会消失。
【判断题】
差动电容式差压变送器主要包括变换器和测量电路两部分．
【判断题】
零漂是指仪表在参比工作条件下，输入一个恒定的值时的输出变化。
【判断题】
双闭环比值调节系统由三闭环回路，当主参数受干扰变化时副参数跟踪变化，当副参数受干扰变化时主参数不变化。
【判断题】
离心泵流量控制有直接节流、改变转速、旁路回流量调节等控制方式。
【判断题】
随着DCS和PLC的发展，两者之间的界线越来越模糊，功能相互渗透。
【判断题】
现代可编程序控制的输出信号有开关信号、数字信号、频率信号脉冲信号和模拟信号等。
【判断题】
差压计或差压变送器正负压室与测量管道的连接必须正确，引压管倾斜方向和坡度以及隔离器、冷凝器、沉降器、集气器的安装均应符合设计文件的规定。
【判断题】
综合控制系统是一个总称，它包括计算机控制系统、分散控制系统、可编程序控制系统、现场控制系统和计算机集成制造系统等。
【判断题】
仪表控制系统有检测系统、控制和调节系统、报警系统、联锁系统和综合控制系统等。
【判断题】
涡轮流量变送器输出信号的电压与流量成正比。
【判断题】
自动调节系统常用的参数整定方法有经验法、衰减曲线法、临界比例度法、反应曲线法
【判断题】
测量一个电路的电流，电流表必须和这个电路串联。为了使电流表的接入不影响电路的原始状态身的内阻抗要尽量小。
【判断题】
构成A/D转换器的方法有：计数式A/D转换、逐次逼近型A/D转换、双积分式A/D转换、串-并行A/D转换。
【判断题】
压力开关的工作原理是：当被测压力超过额定值时，弹性元件的自由端产生位移直接或经过比较后推动开关元件，改变开关元件的通断状态，达到控制被测压力的目的。
【判断题】
按输入信号形式分，数字显示仪表有电压型和电流型两类。
【判断题】
电压型数字仪表一般和输出电压的传感器或变送器配合使用。
【判断题】
频率型数字仪表一般和输出频率的传感器或变送器配合使用。
【判断题】
数—模转换器的功能是把连续变化的模拟量转变为在数值上等价的离散数字量，它是数字显示仪表的核心部件。
【判断题】
间称为仪表的反应时间。如果仪表不能及时反映被测参数，便要造成误差，这种误差称为静态误差。
【判断题】
自动调节仪表按所使用的能源不同可分为气动调节仪表，液动调节仪表，电动调节仪表和混合式调节仪表。
【判断题】
自动控制系统内测温传感器主要使用热电偶和热电阻两种。
【判断题】
PID调节器的整定参数是比例带，积分时间和微分时间。
【判断题】
集成运算放大器的应用电路包括信号运算和信号处理两种。
【单选题】
l．在封建社会，中国封建政府实行的阻碍商品经济发展的政策是 ___
A. 闭关锁国
B. 高利贷
C. 重农抑商
D. 重商抑农
【单选题】
中国封建社会政治的基本特征是 ___
A. 高度中央集权的封建君主专制制度
B. 族权和政权相结合的封建宗法等级制度
C. 国家统一和各民族经济文化紧密联系
D. 结构稳定、延续，发展缓慢、迟滞
【单选题】
中国封建社会宗法等级制度的核心是 ___
A. 夫权
B. 父权
C. 宗族家长制
D. 君权
【单选题】
中国封建社会的文化思想体系的核心是 ___
A. 法家思想
B. 道家思想
C. 墨家思想
D. 儒家思想
推荐试题
【单选题】
Tom is a book lover. ______ likes reading very much.
A. He B. She C. You D. It
【单选题】
—May I listen to the music here, Mr. White?
—Sorry, you’d better it like that．
A. not to do B. not do to
C. dont do D. not do
【单选题】
3.—Did you have a good time at Lauras birthday party?
— Yes, indeed. Its several years ________ I enjoyed myself so much.
A. when B. before C. since D. that
【单选题】
4. —___________ is the Summer Palace from here?
About three kilometers away. You can take the No. 35 bus.
A. How long B. How far C. How often D. How much
【单选题】
5. I was looking for a birthday gift for my mother, but I couldnt find ______ suitable.
A. anything B. something C. nothing D. everything
【单选题】
6. A friend of my ____ and I are going to visit_______ next week．
A. father; Browns B. father's; Browns
C. father; the Browns D. father's; the Browns
【单选题】
7. She ______ very hard since she came to our school.
A. studies B. has studied C. is studying D. studied
【单选题】
8. — Who will send you to the new school, your mom or your dad?
— _______. Ill go there by myself.
A. Both B. Either C. Neither D. None
【单选题】
9.—Well do what we can ____English well this term．
—It’s high time for you to work hard．
A. study B．to study C. be studied D. be studying
【单选题】
10. —I’m going to Flower Bookstore. Could you tell me ______?
— Sorry, I don’t know. I’m new here.
A. where it is B. where was it C. where is it D. where it was
【单选题】
11. How do you like the dishes, Eric?
— Fantastic! Nothing tastes ________.
A. nice B. better C. terrible D. worse
【单选题】
12. ______ Lin Feng has to work late, she always wears a smile on her face.
A. Because B. If C. Until D. Though
【单选题】
13.You can save money _______ you buy cheaper things.
A. before B. unless C. if D. until
【单选题】
14. We will have a _________ holiday after the exam．
A. two-month B. two month’s C. two month D. two-months
【单选题】
15. —We will build an underground in Xuzhou before 2015．
— Wow, _______! Will it pass our place?
A. what an excited news B. how excited the news is
C. what exciting news D. how exciting
【单选题】
16. — Emily, here’s a dictionary．I hope it will help you in some way．
— Thank you．It’s ________ what I need．
A. almost B. still C. only D. just
【单选题】
17. —Oh．I’m hungry．Mum, can I have the hamburger on the plate?
—No．It tastes ．
A. terribly B. terrible C. good D. well
【单选题】
18. —We can invite our teachers to the farewell party next Saturday.
—Yes, ______? I’ll call them at once.
A. what for B. what C. why not D. why
【单选题】
19.You can ________ ask the old man to move away to any other place because he has lived ________ here for at least sixty years．
A. hardly; alone B. hard; alone
C. hardly; lonely D. hardly; lonely
【单选题】
20.—I’m going back to see my grandparents this weekend．
—________．
A. It’s very nice of you B. You’d better hurry
C. Say goodbye to them D. Give my best wishes to them
【单选题】
21.—Why not take ____ umbrella with the sign “Made in China”? It is useful.
—What _______ good advice it is!
A. an; a B. a; a C. an; \ D. \; a
【单选题】
22. —Do you know the boy________ is sitting next to Peter?
— Yes. He is Peter’s friend. They are celebrating his ________ birthday.
A. who; ninth B. that; ninth C. /; ninth D. which; ninth
【单选题】
23. It was dark, ______ I couldnt see what was happening.
A. or B. though C. but D. so
【单选题】
24.—You can use MSN to talk with Vivien on the Internet.
—I know. But can you tell me ________?
A. what I can use it B. when I can use it
C. why can I use it D. how can I use it
【单选题】
25. _______ are you going to the School Uniform Exhibition, Amy ?
To learn about different styles of school uniform.
A. What B. Where C. Which D. Why
【单选题】
( ) 26. Where does the writer of "The little Prince" come from?
A．England． B．France． C．America． D．China．
【单选题】
( ) 27. What does the prince do after the fox tells him a secret?
A．He cares more about a flower and a sheep．
B．He meets many more strange adults on other planets．
C．He realizes his love for the rose and he goes back to his planet．
D．He discovers interesting things such as a snake, other roses and a fox
【单选题】
( ) 28. What does "The little Prince" mainly talk about? It' s about _________．
A．the adult world B．the planet B -612
C．a rose and a fox D．the adventure of a young prince
【单选题】
( ) 29. What is the writer's main purpose（目的）in writing this passage？
A．To tell the readers his life story．
B．To tell people what kind of person his father was．
C．To tell the readers what present he got from his father．
D． To let people know how poor he was．
【单选题】
( ) 30. Why did the father not ask his son not to do this and do that？
A．Because he felt quite confident of his son．
B．Because he was born from a poor family．
C．Because he was a man of few words．
D．Because he didn't want to be much too strict with his son．
【单选题】
( ) 31. What would someone learn from this passage？
A．How to live by oneself． B．How to stand on one's own feet．
C．What a good father should do． D．What the self-important is like．
【单选题】
( ) 32. What may be the proper Chinese for the underlined part in the passage？
A．闲暇时光 B．学费 C．精神空虚 D．经济不足
【单选题】
( ) 33. Why did Natalie Smith pay for the six cars behind her?
A. She had seven tickets.
B. She hoped to please others.
C. She knew the car drivers well.
D. She wanted to show kindness.
【单选题】
( ) 34. Judy Foreman copied down the phrase because she ___ .
A. thought it was beautifully written
B. wanted to know what it really meant
C. decided to write it on a warehouse wall
D. wanted her husband to put it up in the classroom
【单选题】
( ) 35. Who came up with the phrase according to the passage?
A. Judy Foreman. B. Natalie Smith. C. Anne Herbert D. Alice Johnson.
【单选题】
( ) 36. What can we infer from the last paragraph?
A. People should practice random kindness to those in need.
B. People who receive kindness are likely to offer it to others.
C. People should practice random kindness to strangers they meet.
D. People who receive kindness are likely to pay it back to the giver.
【单选题】
( ) 37.The greatest river for navigation is ___________.
A. the Nile B. the Amazon C. the Mekong D. the Mississippi
【单选题】
( ) 38. From a dam, people can use the water for ___________.
A. keeping the rivers clean B. only making electricity
C. irrigation and making electricity D. washing clothes
【单选题】
( ) 39. The water in the river is polluted because of _____________.
A. people's drinking water too much B. people's swimming in the river too much
C. chemicals and other materials D. people's building a dam across a river
【单选题】
( ) 40. The best title of the passage is ___________.
A. Rivers in Cities B. The importance of Rivers
C. Transportation D. Natural Resources
