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Unformatted text preview: EE 4770
Problem 1: Homework 1 Due: 5 February 1997 Design a system for converting process variable x 2 0; 125 m , the length of magnetic 1 tape wound on a spool, to a oating-point number length = H x = x m . The tape is 15 m thick and does not shrink or stretch; it is wound tightly on the spool so there is no space between the layers of tape. The inner diameter of the spool without tape is 5 mm. The radius of the surface layer of tape can be determined by a mechanical contact free to move radially so its position is linearly related to the surface-layer radius. The solution should: Specify a transducer to convert the position of the mechanical contact to an electrical quantity. You are encouraged to choose the transducer so that the conditioning circuit is as simple as possible. Show the mapping between tape length and surface-layer radius. Show the mapping between outer radius and transducer response1. Use a 5-volt, 8-bit, analog-to-digital converter. Design the conditioning circuit to make full use of the ADC's dynamic range. Show the mapping between ADC output and length, Hf . Include a schematic showing all component and supply values. Include pseudocode for the interface routine; specify values for all constants. Determine the precision of the value written to length in the problem above. Problem 3: Design a system for converting process variable x 2 0; 125 m , the length of magnetic tape wound on a spool, to a voltage H x = x 10 V . The tape and mechanical parts are the same m as above. The solution should use only analog components. See footnote for hint2 .
Problem 2: 1 Since a variable resistor is the only transducer covered, transducer response" can be replaced with transducer resistance." 2 Hint: Use two variable resistor transducers measuring the same displacement and use each in a di erent inverting ampli er. 1 ...
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This note was uploaded on 11/28/2011 for the course EE 4770 taught by Professor Staff during the Fall '99 term at LSU.
- Fall '99