In a production plant, heated metal boxes are cooled, by a strong blowing fan, as they move
Question:
In a production plant, heated metal boxes are cooled, by a strong blowing fan, as they move on a transfer belt (see figure). The timing belt is always moving. A presence sensor A (ON/OFF) as shown in the diagram provides a "high" signal as long as a box is passing under it and provides a "low" signal when there is nothing underneath. The metallic boxes should be cooled alternately fast or slow to produce harder or softer boxes. Therefore, "high" and "low" fan speeds should be used alternately with every other box (one fast-cooled, one slow-cooled, and so on).?
(a) You are asked to build a simple logic device (controller) that uses the presence sensor signal A as the input to generate an output Y that changes the speed of the fan, for every other box, to low and high (logic Y-0 for low fan speed and logic Y-1 for the high speed). To design this device, you have access only to one negative-edge triggered JK flip-flop and some other simple gates (the total number of the simple gates you may use cannot be more than five). Briefly explain how your designed circuit works and use timing diagram in your explanation when necessary. Hint: start by looking at the timing plot of the output of the sensor A and the timing requirements of the controller output Yas a result.
(b) To save cost, the management has decided to process their new type of non-metallic boxes in the same production line. As a result, there will be non-metallic boxes (with the same dimensions) coming on the same transfer belt in a random order. You decide to use a metal sensor M in the same place as the presence sensor A to detect if a part is metallic or not. Sensor M (outputs a logic high when it is in close proximity of metals and low for any other case). The non- metallic boxes are to be always cooled fast (high fan speed). However, for the metallic boxes, it is still very important to keep the same sequence (alternating slow and fast) as they enter the cooling station independently from occasional non-metallic boxes. Modify your logic device designed for part (a) of the problem to accommodate for this requirement. Again, you have access only to one negative-edge triggered JK flip-flop and some other simple gates (the total number of the simple gates you may use cannot be more than five). Briefly explain how your designed circuit works and use timing diagram in your explanation when necessary.
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Vector Mechanics for Engineers Statics and Dynamics
ISBN: 978-0073212227
8th Edition
Authors: Ferdinand Beer, E. Russell Johnston, Jr., Elliot Eisenberg, William Clausen, David Mazurek, Phillip Cornwell