Fig 1.0 Distance E and F is known while distance L is calculated by measuring time travel D
Radar gages are extremely popular because of their ability to measure tank levels non-intrusively in the Philippines. Previously only a handful of manufacturers were able to produce high quality microwave based measuring devices but now with the wide acceptance, this type of gage has become more prevalent in applications that previous used some hydrostatic, magnetic or electrical based type of level measurement.
How do radar gauges work?
Sometimes radar gauges are confused with ultrasonic level gauges because both are using non-intrusive techniques. The radar gage operates at much higher frequencies than ultrasonic technologies and the system is low powered while able to execute a very short pulse. In fact, the wave velocity is sent at the speed of light. The microwave pulses are sent into the tank (normally from the top) and the time taken for the pulse to reflect back from the substance in the tank (whether liquid or solids) is measured. Coupling this technique with modern day electronics and software, it is possible to easily reject a false echo.
Accuracies to millimetre levels can be achieved using a properly selected and installed radar level gage. The tank level can be programmed to send a remote reading through a 4-20mA signal to a digital display , PLC or through a Modbus system.
