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 Level System |
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 Level System Schematic Diagram |
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The "Tank" is where the pump sends the water. The water drains by gravity
out of the tank. The system actually has two tanks to allow you to run experiments with either tank. One tank is about 6-inch diameter, the other about 2-inch diameter. From a useful diagram point-of-view, the existance of two tanks is not relevant. The level in the tank is detected (PT/307) by a piezoresistive pressure cell. It has an output of 0-5 VDC. This goes to a analog-to-digital board in the computer that converts it to a signal that the controller software recognizes. The computer is the level-recording-controller (PRC/307). The digital-to-analog board in the computer sends a voltage (0-100% of 10 volts DC) to an Analog Devices signal conditioner that converts it to a 4-20 ma signal that the pump driver (PZ/307) recognizes. The variable-speed pump receives a signal from the computer telling it how fast to pump the water.
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