如果结果不匹配，请 
更多“HART通信程序也即为HART协议数据链路层和应用层的软件实…”相关的问题
A.HART频率点的回路阻抗不够，回路中另外串入一个250欧姆电阻。将引线接到电阻两端，检查通信是否恢复
B.现场设备终端处回路电流和电压不足，确认现场设备终端处至少有4mA电流和12VDC电压
C.现场设备可能设置成非零的HART地址(多节点模式),将轮询模式修改为除“从不轮询”以外的模式，例如，数字轮询
D.以上全是
A.SEND(发送)-把你已经输入的信息发给仪表
B.HOME(主菜单)-返回Online(在线)菜单
C.ABORT(放弃)-取消你的输入并返回到你已经选择的当前变量或例行程序的菜单，变量值不会改变
D.ENTER(进入)-发送你已经选择的信息给HART内部处理器或给将要发送的数字加上标记
Which of the following statements concerning Tennessee Williams is NOT correct？
A．He has been influenced by Anton Chekhov,D. H. Lawrence and Hart Crane.
B．His last Broadway play is named Clothes for a Summer Hotel.
C．The recurrent themes in many of his plays are loneliness and desire.
D．He was awarded Nobel Prize for his brilliance as a dramatist.
A.在主菜单上双击“HARTApplication”运行HART应用
B.在主菜单上双击“FoundationFieldbusApplication”运行现场总线应用
C.在主菜单上双击“Settings”查看设置菜单
D.在主菜单上双击“ListenforPC”，启动与PC的IrDA通讯(红外通讯)，推荐的最大距离为18英尺
听力原文：W: Hello. Worldwide Flowers. Ms. Hart is speaking.
M: This is John Hill. I'd like to order some flowers and have them sent to my home.
W: Fine, Mr. Hill. What kind of flowers did you have in mind？
M: I'd like to send a dozen red roses.
W: A dozen red roses. Our long-stem red roses are selling for twelve pounds a dozen this week, and they are really quite nice.
M: All right then. I'll take those.
W: I'll need your complete address with the zip code, Mr. Hill.
M: The address is 84 Richmond House, Park Village East, London NW 4 3ET, UK.
W: What would you like us to put on the card？
M: Hm, just something simple. How about: All my love, John.
W: Ok. Now, when should they arrive？
M: They should be there before five in the afternoon on June the 17th.
W: That should be no problem. Just one more question, Mr. Hill. How do you intend to make payment？
M: You can put it on my Visa card. The number is JH 327, 2645.
W: That should do it. Thank you for calling Worldwide Flowers, Bye.
(20)
A．A dozen long-stem red roses.
B．A dozen short-stem red roses.
C．A dozen long-stem white roses.
D．A dozen short-stem white
B、确认回路的阻抗至少为250欧姆。如果没有外部阻抗，通常总阻抗就是监视回路的过程指示设备的阻抗
C、根据过程指示设备的手册，确认其回路阻抗。如果过程指示设备的阻抗未知，则可以通过回路的电流和过程指示设备上的电压来确定。阻抗可以通过公式计算，阻抗=电压/电流
D、375型现场通讯器不可用于测量电压
The manufacturer who increases the unit price of his product by changing his package size to lower the quantity of delivered can, without undue hardship, put his product into boxes, bags, and tins that will contain even 8-ounce, one-pound, two-pound quantities of breakfast foods, cake mixes, etc. A- study of drugstore and supermarket shelves will convince any observer that all possible sizes and shapes of boxes, jars, bottles, and tins are in use at the same time and, as the package journals show, week by week, there is never any hesitation in introducing a new size and shape of box or bottle when it aids in product differentiation. The producers of packaged products argue strongly against changing sizes of packages to contain even weights and volumes, but no one in the trade comments unfavorably on the huge costs incurred by endless changes of package sizes, materials, shapes, art works, and net weights that are used for improving a product's market position.
When a packaging expert explained that he was able to multiply the price of hard sweets by 2.5, from 1 dollar to 2.50 dollars by changing to a fancy jar, or that he had made a 5-ounce bottle look as though it held 8 ounces, he was in effect telling the public that packaging can be a very expensive luxury. It evidently does come high. When an average family pays about 200 dollars a year for bottles, cans, boxes, jars and other containers, most of which can't be used any more but stuffing the garbage can.
What started the public and Congressional concern about deceptive packaging rumpus？
A．Consumers' complaints about the changes in the package size.
B．Expensive packaging for poor quality products.
C．A senator's discovery of the tricks in packaging.
D．The rise in the unit price for many products.
