The Model 4042 Liquid Level Controller monitors, displays and controls water level up to 34.6 feet, in a tank or reservoir. The Model 4042 operates from the 4-20mA input signal provided by the Time Mark Model 450 Pressure Transducer. This 4-20mA signal represents the water level to be controlled, where 4mA equals zero feet, and 20mA equals 34.6 feet. A liquid crystal display (LCD) is provided to show the water level during normal operations, and the set-point values during calibration. There are four user-adjustable trip set-points. As the water level rises above each trip point setting, the front panel LED for that level illuminates, and the corresponding output relay energizes. A 4-20mA output, which tracks the 4-20mA input, is also provided. This signal output can be rescaled to different ranges of level by the user. A test control, that stimulates an input signal, is available on the front panel. The test control is useful for checking the trip set-points, and overall system operation.