A manufacturer produces two types of parts, one made of metal and one made of plastic. The machines that produce the parts dump them on a main conveyor. The company wishes to develop a sorting system that will sense which part is coming down the main conveyor and divert the part down the appropriate lane for packaging. It has been suggested that non-contact sensors be used to sense the part before it reaches the diverter lane. After a time delay, the diverter could be energized to push the part down the diverter lane. The diverter rods have limit switches that are enabled when they reach the end oftheir stroke. The situation is shown in Fig. 3.35. You have been asked to participate in the design of the system. (a) Which lane would you use to divert the plastic part and which sensors would you use? The metal part? (b) Assuming you are using a controller with parallel ports Band C as defined in Fig. 2.37, define all the inputs and outputs you would need to control the system.

Address Internal RAM OOFF 0100 O1FF Address User RAM Port A 1000 Port C 1003 Port B 1004 Port Replacement Unit 103 Port C DDR 1007 1008 1009 Port D B600 EEPROM B7FF Monitor ROM and Interrupt Vectors FFFF Fig, 2.37 Memory map of Motorola MC68HC11EVBU controller in signal chip mode. Address Internal RAM OOFF 0100 O1FF Address User RAM Port A 1000 Port C 1003 Port B 1004 Port Replacement Unit 103 Port C DDR 1007 1008 1009 Port D B600 EEPROM B7FF Monitor ROM and Interrupt Vectors FFFF Fig, 2.37 Memory map of Motorola MC68HC11EVBU controller in signal chip mode