The application described in this document is used to manage the level of a liquid in a tank. The tank is filled by a pump, and drained using a valve.
The level of the tank is measured with an ultrasonic sensor placed below of the tank.
The volume of the tank is shown by a digital display.
The desired level of liquid is defined by the operator, using a potentiometer
The application’s operation control resources are based on an operator screen, which shows the status of the various sensors and actuators, as well as the level of the tank.
The high tank level is defined through the operator screen.
This is the application’s final operator screen:
The operating mode is as follows:
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A potentiometer is used to defined the desired level.
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A Start Cycle button is used to start the filling.
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When the desired level of the tank is reached, the pump stops and the Tank ready led lights up.
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A Drain tank button is used to start the tank draining.
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When the low level of the tank is reached, the valve closes. The Start Cycle button is used to restart the filling.
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A Stop Cycle button is used to interrupt the filling. Pressing this button allows you to set the system to a safe level. The pump stops and the valve opens until the low level is reached (tank empty). The valve closes.
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The pump has a variable flow rate, the value of which can be accessed by the operator screen. The more the level of liquid is raised, the more the flow is reduced.
The flow rate of the valve is fixed.
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A safety measure must be installed. If the high level is exceeded, a safety measure is activated and the system is set to failsafe. The pump then stops and the valve opens until the low level is reached (tank empty). The valve closes.
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For failsafe mode, an error message must be displayed.
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The time that the valve is open and closed is monitored, with an error message being displayed if either of these is exceeded.
