Instrumentation for Simultaneous Recording of Water Level in Digital and Graphical Forms

Abstract

ABSTRACT THE increasing demand for reliable and detailed water-use data in irrigation has encouraged the use of digital data acquisition systems. An instrumentation system for simultaneous recording of water table heights in digital and graphical forms was developed. The major components of this device were a Stevens Fl recorder, an electronic datalogger, and a float-potentiometer (float-pot) unit. The instrumentation system has worked very well for monitoring water levels at a stream flow station in an irrigation canal, where water level changes rapidly. The Float-Pot unit electronically transferred absolute water level positions to an electronic datalogger in any preset incremental time interval, while mechanically operating the clock-driven pen carriage and chart drum recorder. Data stored in the datalogger were transferred to floppy disk through an RS-232 communication interface and a portable IBM-compatible microcomputer. The raw data were processed, transformed into water levels, and compared with those simultaneously obtained by the chart. The results indicated that the data obtained by the float-pot/electronic datalogger were highly accurate. The proposed sytem has provided an excellent concurrent digital and graphical record of the water level positions with a high level of accuracy.