mt_sol

mt_sol - Name Solution Real Time Computing Systems EE 4770...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Name Solution Real Time Computing Systems EE 4770 Midterm Examination 17 March 1999, 8:40-9:30 CST Alias Problem 1 (50 pts) Problem 2 (50 pts) Exam Total (100 pts) Good Luck!
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Problem 1: The partially designed circuit below is to be used to convert temperature x [ - 20 C , 40 C] to a floating-point number H ( x )= x/ K to be written into variable temp . The circuit uses an RTD, its model function is H t1 ( x )= R 0 (1+ α 1 x ), where R 0 = 100 Ω and α 1 =0 . 00398 / C. The RTD is connected to a - 7V source as shown. The ADC response is H ADC(10V , 16b) . + - v 1 v 2 R 2 R 3 -7 V ADC B I RTD ( a ) Complete the design (choose values for v 2 , R 2 and R 3 ), so that the ADC input is in [0 . 5V , 9 . 5V] over the range of temperatures to be measured. (20 pts)(For reduced credit [ < 20 pts] make full use of the ADC dynamic range.) First, find the voltage at the ADC input: H c ( H t1 ( x )) = - R 3 ± v 1 H t1 ( x ) + v 2 R 2 ² Call the resistance at the minimum temperature R min and the resistance at the maximum temperature R max .U s i n g the boundaries of the temperature range R min = H t1 ( - 20 C) = 92 . 04 Ω and R max = H t1 (40 C) = 115 . 92 Ω . As stated in the problem, the ADC input should be a minimum of 0 . 5V this occurs at the maximum temperature: H c ( H t1 (40 C)) = 0 . 5V= - R 3 ± v 1 R max + v 2 R 2 ² . Similarly the ADC input must be 9 . 5V at - 20 C or H c ( H t1 ( - 20 C)) = 9 . 5V= - R 3 ± v 1 R min + v 2 R
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 5

mt_sol - Name Solution Real Time Computing Systems EE 4770...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online