Question

QUESTION 5 Serial communication between devices can be in three different modes. They (a) are simplex, half duplex and full duplex. Explain the different of all three serial communication modes and give one example of each mode. (7 marks) Discuss the advantages and disadvantages of RS-232 interface (b) (5 marks) Determine the binary equivalent of 8.735V for successive approximations ADC having (c) 4 bits output and reference voltage of +12V (6 marks) A control valve has a linear variation of opening as the input voltage varies from OV - (d) 1ov. A microcomputer outputs an 8 bit word to control the valve opening using an 8 bit DAC to generate the valve voltage Find the reference voltage required to obtain a full open valve (10V) (i) Find the percentage of valve opening for lbit change in the input word. (ii) (7 marks

Answer 1

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12 Resoluton 21 46 t0.75 Min ADC How GReselutim 8.735 fl164 E 11 5I01 Binany equivaen Fof 8-735 V IS 011 ence lov voltuge ful Scale given 419 te N 10 Resolutim Resal ution X(2"-1) Reference vol tage (i) x (19-1) 28 10 10 x25 10 x 255 27 E 9 96 V

oP valve opuning perentage The 2"-1) co (23-1) 0 39/ 0:41