The Greyline Instruments Bigfoot level velocity transmitter is a sealed, ultrasonic sensor for continuous water measurement in open channels and partially filled pipes. Bigfoot can be mounted on the bottom of a pipe or channel to accurately measure and transmit both water level and velocity. No calibration is required.

The Bigfoot can be powered from batteries, solar charging systems, or DC power supplies. Its 4-20mA outputs can be connected to data loggers, SCADA systems or PLC measuring systems. Flow is calculated from the Bigfoot transmitter outputs by using the formula: Flow = Area x Velocity, where Area is the cross-sectional area of the channel at the level measured by the Bigfoot, and Velocity is the speed of the water. It can be mounted in pipes, culverts, channels, or ditches with defined dimensions. Bigfoot generates ultrasonic signals that are projected into the water to measure flow velocity and level. Some solids or bubbles in the water are required for proper velocity measurement.

Level measurement range is 1.8 to 144.8in (45.8 to 3678mm) from bottom of sensor with accuracy of ±0.25% of actual range or 0.04in (1mm), whichever is greater. Velocity measurement range is 0.1 to 9.84 ft/sec (0.03 to 3.0 m/sec) with accuracy of ±2% of reading. Repeatability and linearity are ±0.1%. Outputs are 4-20mA for both velocity and level with 1000 ohm load capability at 24VDC. Power input is 12-24VDC, 200mA max. Automatic continuous temperature compensation ensures accurate measurements across varying conditions. The 50ft (15m) submersible sensor cable is 6-conductor, 18 ga. Applications include irrigation, stormwater, stream flow, and wastewater.