问题 问答题 简答题

集散型控制系统是如何提高系统的功能和效率?

答案

参考答案:

集散型控制系统的功能和效率的提高是因为由微型机构成的控制装置,其控制功能通过程序来完成。过程控制中常用的功能块,如三态PID调节器、积分器、微分器、运算器、计时器、均衡器、峰值检测器、顺序工作器、比较器、记录器、多工转换器、超前滞后环节及跟踪保持环节等几十种功能模块,用相应的子程序群来实现,这些软件功能块通常以固件的形式构成。

通过操作按键,对这些功能模块可任意选择,进行串并连接以实现各种复杂的控制,如非线性控制、串级控制、前馈控制、优化控制、适应控制、超驰控制这就是通常所说的灵活组态功能。这种装置的最显著特点就是操作的简便性,技术人员或操作人员就像使用他原来熟知的模拟仪表一样,因而这种控制装置也称为伪模拟调节器,操作人员不需要考虑程序设计问题,他的主要精力集中在如何有效运用已有的功能模块来制定他所希望的控制方案。

阅读理解

When many of us take a vacation, more than anything, we seek to relax. We spend long, lazy days on a beach chair or in a hammock(吊床). But too often, we return home, tired.

It doesn’t have to be this way.

In fact active vacations are often the most relaxing of all. We don’t expect you to take up jogging(慢跑), or climbing. Rather, we ask the sedentary(久坐的) vacations among you to spend two to four hours a day doing things, such as walking in the city street, going to a zoo or biking along the ocean.

These kinds of activities aren’t just good for your physical health. They improve your mental health, even your spiritual health. Here are some fresh ideas to make your vacations as pleasurable as they are active and healthy.

A walk at dawn or dusk helps keep you young. Try to make this a daily habit of life when you’re away from home, and you will guarantee yourself both physical and spiritual refreshment.

Don’t allow yourself to spend all your time sitting in front of water. Whether it is the ocean, a swimming pool, or a tree-lined lake, make sure you get into the water for swimming or games, or even walking. Merely standing in waist-high water is a good workout, thanks to the action of the water. And you’ll feel so much more active!

Many of us spend a large chunk of our vacation on the road, either getting to and from our destinations, or using the car for sightseeing. But no matter how beautiful the scenery is, great, memorable vacations don’t happen in a car seat. Frequently get out and stretch, walk, picnic, shop, visit, and have fun. It’s important for your health and energy, and it makes traveling a lot more active and interesting

小题1: The idea in the text is mainly to _______.

A.suggest ways to make vacations relaxing

B.suggest places for relaxing vacations

C.explain the reasons for having vacations

D.explain the relationship between vacations and health小题2: Which of the following can be considered as a form of exercise?

A.Sitting by a lake.

B.Standing in water.

C.Staying in a car.

D.Enjoying beautiful scenery.小题3:In the last paragraph, the author seems to advise us to _______.

A.have vacations frequently

B.get out of the car frequently

C.go on vacations on foot

D.stay in a car seat

多项选择题