4-20mA output open channel flow meter river measurement

Ultrasonic Doppler Principle in Quadrature Sampling Mode is utilised to measure water velocity. The 6537 Instrument transmits ultrasonic energy through its epoxy casing into the water. Suspended sediment particles, or small gas bubbles in the water reflect some of the transmitted ultrasonic energy back to the 6537 Instrument’s ultrasonic receiver instrument that processes this received signal and calculates the water velocity.

Water depth is measured with two methods. An ultrasonic depth sensor measures water depth using the ultrasonic principle from a top mounted sensor on the instrument. Depth is also measured using the pressure principle from a bottom mounted sensor in the instrument. These two sensors provide flexibility in depth measurement. Some applications, for example measuring from the side of a pipe, better suits a pressure principle, while other applications in clear open channels better suit an ultrasonic principle.

The 6537 Instrument has a 4 electrodes conductivity instrument (EC) included to measure the quality of the water, with four electrodes exposed to the water at the top of the instrument. Water quality is measured on an ongoing basis and this parameter can be recorded along with velocity and depth to better analyse the nature of the water in open channels and pipes.