Ultrasonic level sensor

As previously mentioned you have many options for level transmitters, one of the most prominent is an ultrasonic level sensor. The ultrasonic level sensor is mounted on the top of a holding tank, side mounted into a pit or sump, or even used for small tank monitoring as they are becoming more and more affordable. The issue with submersible level sensors is that the operator must be aware of the media’s specific gravity. This is because submersible level sensors are continuously monitoring the weight on a diaphragm. If the operator is unaware of the specific gravity or if it changes due to temperature, then he will often look at installing aultrasonic level sensor. The ultrasonic level sensordetects the current level and monitors it continuously by transmitter a sound, the sound then travels and bounces off of a reflective surface and the ultrasonic level sensor measures the time of flight. 

The ultrasonic level sensor will then transmit a 4-20mA signal or 0-10V to a remote display / controller or PLC unit. It is often found that in large facilities the ultrasonic level sensor will be directly wired into a SCADA system so that the operator can monitor the reading from the ultrasonic level sensor on a PC or television. The operator can zoom in and highlight each independent ultrasonic level sensor and view the current readings remotely making it very simplistic to determine which condition his tanks are in. Some ultrasonic level sensors will actually have relay outputs often used for pump or valve control. For example, if the ultrasonic level sensor were to read a low level input that the operator entered it will activate the relay output and close a valve to prevent more liquid from leaving that holding tank. Alternatively, once the ultrasonic level sensor could continuously monitor the tank level and once the ultrasonic level sensor detects a high level it could activate a pump. The ultrasonic level sensor would let the pump know that it is time to pump down the liquid level to the operators desired level and then turn off.

There are several applications where an ultrasonic level sensor should not be recommended and those involve factors such as foam, vapor, turbulence and condensation. These factors will not be ideal for the ultrasonic level sensor and you can expect inaccurate readings which will mislead the operator or equipment that is connected to the ultrasonic level sensor. Having a sensor such as an ultrasonic level sensor that requires a return signal from the emitted noise you need to ensure that the sensor does not go lost or you will lose your reading. There are ways to install an ultrasonic level sensor and prevent some of the factors in the tank from misleading it. One of which is to install a standpipe around the ultrasonic level sensor, this liquid level will travel up the standpipe and the foam and vapor will remain on the outside of the standpipe. So if you are installing aultrasonic level sensor in an application where these factors are present that you will want to take precautions and install a standpipe.

Our more products: Liquid Level Sensor, Level Sensor