Need Some Help With These Home Work Problems 1 (80.06 KiB) Viewed 13 times
Speed If we have a 8 cylinder engine operating at 10,000 RPM, approximately how fast a processor do we need if we would want to control the timing of each spark? Lets make some assumptions here: • 8 sparks per revolution • The processor takes 20 just a number I picked for computation sake) clock cycles to do the processing for each spark. First calculate the revolutions per second: Next calculate the clock cycles per second required as Hz (cycles/second) Does the clock speed fall into the realm of microcontrollers (10's of MHz) or microprocessors (-Ghz)? PLC's - how do they fit into this? Many of you have taken PLC classes and ask how do PLCs fit into the picture? A functional diagram of a PLC system as shown below is cquivalent to what a microcontroller does. The hardware is usually optimized for ruggedness to operate on the factory floor and to use the specialized programing environment of PLCs. Depending on the requirements of a PLC, the underlying processor may either by a microcontroller, a microprocessor, or some specialized processor arrangement. Programming Device External Component, HMI Programmer Communicate wis come Communication Interface RAM Memory EPROM Permanent RAM w ROM Owing ws
Take an example of a beverage bottling line running at 200 bottles per minute. Just as an example let's assume each battle requires 100 lines of PLC code with each line taking a processor cycle. 1. Converts bottles per minute to bottles per minute 2. Calculate cycles per second = a Your answer should come out well within the range that a microcontroller running at 20MHz can handle. However, note that PLCS may do a lot more, for example handling high speed Ethernet communications so some have processors closer to the range where a typical microprocessor may be used for the control. 1
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