S215   081003

Lab HJ03-15 Right Half of System
(as viewed from grinder)
Unloading System (for wood pellet raw material)
OEES 215
10 points

Rules Unload Box 2 When us2 is low, turn hy2 on (because box has space). When us2 is high, turn hy2 off (because box is full) Unload Box 3 Same as unload box 2, except use us3 and hy3 stprh (Stop Right Half) If either us1 or us4 is high, send out a high on stprh If both us1 and us4 are low, send out a low on stprh Switches    us4  us1 us3 us2 LEDs            stprh hy3 hy2 Glossary hy2 = Hydraulics for operating the walking floor in the truck at box 2. hy3 = Same thing for box 3. stprh = Stop right half of system. (Used to shut down conveyors ub2, ub3, mxc, and uc.) us1 = Ultrasound sensor to sense when box 1 is getting full. (High = material has reached the level of the sensor). us2 = Same thing for box 2. us3 = Same thing for box 3. us4 = Ultrasound sensor to sense when the grinder is getting full. Explanation The grinder motor is so large, that turning it off and on is undesirable. Thus it is simply left on while the system is running. When us1 goes high, box 1 is almost full. However, the box still has room for material that is still on the discharge conveyor and in the grinder. In order to keep box 1 from overflowing, all conveyors on the right side of the system are shut off, and the grinder is allowed to process whatever material is inside it. The conveyors on the right side of the system are the following: ub2, ub3, mxc, and uc. When us4 goes high, the grinder is full, and all conveyors on the right side of the system are shut off. Thus, if either us1 or us4 go high, the conveyors on the right side are shut off. Unloading of material from trucks into boxes 2 and 3 may continue, even if conveyors on the right side are off. The hydraulic pumps continue turn off and on based on the status of us2 and us3. Of course, if the conveyors are shut down, the boxes will eventually become full and no more unloading can occur until the conveyors start up again.