Container-tank full sensor-indicator using ultrasonic transceiver - stores fixed and false echo profile and subtracts from received signal to determine real amt.

摘要

The container-full indicator consists of A/D converter (2) receiving echo signals from ultrasound pulse illuminated surface of container contents. Echo pulses are filtered and digitised. A microprocessor (4) with memories (5,7) processes input data. Received echo pulses include returns from fixed objects in tank or container. A profile of return pulses is built up during filling/emptying of the container. The echo from the surface to be measured changes as the operation proceeds. Other fixed echoes remain constant and are stored as pulses to be cancelled. Pulses are distinguished by time delay from original transmitted pulse. USE/ADVANTAGE - Improved detector performance by rejection of interference and false echoes by storage of calibration data during filling/emptying operation.