SCADA Tank Level and Pump Control Guide

A tank-level SCADA system continuously monitors water depth using a level sensor and commands a pump to turn on when the tank falls to a pump-on setpoint and turn off when it reaches a pump-off setpoint. Key components include the level sensor (pressure transducer, ultrasonic, float switch, or bubbler), a controller (PLC or RTU) that makes start/stop decisions, a pump control output (relay or variable-frequency drive), a communication link to transmit data remotely, and a power supply with battery backup for sustained operation during outages.

Level sensors convert tank depth to an electronic signal. Pressure transducers and ultrasonic sensors provide continuous 4–20 mA analog output suitable for proportional control and trending; float switches provide only on/off signals and are limited to simple two-point control. Select a sensor with a range matching your full tank depth and mount it to minimize turbulence—submersible transducers near the tank floor, ultrasonic sensors at tank top center away from inlet splash. Route sensor cables in separate conduit away from 120/240 VAC pump power wiring to prevent electrical noise on the signal.

Proper installation prevents erratic pump cycling and false alarms. Seal all conduit entries with approved sealant to block moisture and insects, which can destroy electronics. Verify the 4–20 mA loop is correctly powered and wired before commissioning. A battery-backed UPS sized for 4–8 hours of runtime ensures the system continues monitoring and communicating during power loss, allowing the operator to respond before tank overflow or pump shutdown occurs.