问题 问答题 简答题

工业控制计算机的特点是什么?

答案

参考答案:工业控制计算机在结构性能上与通用机有共性,但由于它专供自动控制用,故在应用上又有其特殊性。它的特点是:

①可靠性高:因为工业过程往往是昼夜运行的,一般的生产装置往往几个月甚至几年才修一次,这就要求控制生产的计算机的可靠性尽可能地高,而故障率要低,平均故障时间要短。

②相对而言,对计算机的精度、运算速度要求较低:工业控制机多为定点机,一般字长较短(16~24位,多为16位),速度较低(每秒几万次至100万次),内存容量较小,当然,随着工业自动化的发展,对工业控制计算机的规模、速度、精度的要求也在不断提高。

③实时响应性好:为及时处理被控对象随时发生的变化并保持诸多数据的同时性,要求计算机在某一限定时间内必须完成处理的工作,即实时响应要好。

④要求有比较完善的中断系统:工业控制计算机要控制生产过程,就必须能自动快速地响应生产过程和计算机内部发出的各种中断请求。这就要求控制机有比较完善的中断系统。

⑤有比较丰富的指令系统:为适应生产过程的自动控制的需要,计算机必须具备较丰富的指令系统,尤其是逻辑判断指令和外围设备控制指令。

⑥要求有较完善的外部设备,特别是过程输入输出设备和各种工业自动化仪表要配套。

⑦有比较完善的软件,包括具有比较完整的操作系统,配备有过程控制所需要的应用软件,使机器的使用更加合理,控制质量更高。

阅读理解

I was offered several part-time jobs at university. Finally I decided to give one of them a go. Now I work in a dining hall on campus(校园). My main duties are to serve food and wash dishes.

I discovered I would have to stand still for at least three hours at a time and was afraid it was not going to be as much fun as I had thought. Smiling all the time and remembering all the strange food names have been a challenge(挑战), too.

I have had really funny experiences. One of the sauces is called "marinara" which is a kind of tomato-based sauce like salsa(辣茄酱). Before I knew what it was, someone asked me to give him the sauce, and I replied: "What? The marijuana(大麻) sauce?" He was astonished. Marijuana is an illegal(非法的 ) drug and has nothing to do with sauce. It was quite embarrassing(使人尴尬的)! I have never forgotten the word "marinara" since then.   

I also had to make a wrap(卷饼) for the first time. I had tasted Mexican wraps many times in China, but making one was a different matter. I could feel my face was burning with sweat and embarrassment as I broke the thin wraps again and again while people were waiting impatiently. Mexican wraps taste great when they're soft, but I do wish they could be made thicker and harder so they wouldn't break so easily.

My favorite part of the job is working in the kitchen. I hold the water cannon(水枪) like a policeman about to fight with "criminals” ----the dirty dishes. It's quite exciting to feel the water rushing out of the pipe. I usually get thoroughly(彻底地) soaked, but it feels good, a bit like taking a shower. Sometimes our boss allows us to play music to cheer us up. I often hum along to the music while washing dishes.  

This is my first experience of being a student worker. It is hard work, but it's turning out to be quite fun.

小题1:Which of the following statements is TRUE according to the article?

A.When the writer works, he has to stand still all day long.

B.The writer had never imagined working in a dining hall could be fun.

C.The writer found making Mexican wraps very challenging.

D.The writer found it easy to keep track of all the weird food names.小题2:When the author made Mexican wraps for the first time, ______.

A.he failed to make them thick and hard

B.he ended up with a few dissatisfied customers

C.he had never tasted Mexican wraps before

D.he was proud of what he had made小题3:What part of the job in the dining hall does the author like best?

A.Making Mexican wraps.

B.Delivering food to customers.

C.Washing dishes in the kitchen.

D.Making all sorts of sauces.小题4:What does the underlined word “soaked “ mean? It means _______

A.湿透了的

B.酗酒的

C.浸泡的

D.渗出的小题5:What is the point in the article?

A.To describe the writer’s fun campus life in the US.

B.To explain the culture of part-time work in the US.

C.To teach readers how to make Mexican wraps.

D.To share the author’s experience of part-time work.

单项选择题