VIRTUAL TECHNIQUES FOR LIQUID LEVEL MONITORING USING DIFFERENTIAL PRESSURE SENSORS

The purpose of presented paper is to demonstrate an innovative approach for low cost continuous liquid level monitoring based on virtual instrumentation. Most o f the traditional measuring systems were designed a d implemented by complicated hardware circuitry. It made the prod uct expensive, with low functionality and with limi ted precision. With virtual measurement technology, more of the in strument can be substituted by software. Using this approach the cheaper and more versatile measurement system can b e developed. As introduction in order to select an appropriate method for liquid level monitoring the comparative analysis of more popular technologies is done. The method for obtaining both liquid density and liquid level with wo differential pressure sensors is suggested and co sidered. Some basic considerations about the modern integrated pr ssu e sensors and some aspects concerning their ca pability for liquid level measurement are done. Finally, a proto type of a liquid level monitoring system based on i ntegrated differential pressure sensors, multifunction data a cquisition board and LabVIEW environment is develop d for measuring liquid level accurately at distances up t o 10 metres. In order to illustrate flexibility of the designed system the front panel of the developed virtual instrument is presented. Measurements carried out in laboratory s how that the accuracy of some millimetres could be achieved.