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A method and apparatus for calibrating a liquid level measurement system of the type having capacitive sensors, by simulating the electrical effects of sensors in an empty condition and their interconnecting cables, at a time when the sensors are full or partially filled. By a sequential balancing t

A method and apparatus for calibrating a liquid level measurement system of the type having capacitive sensors, by simulating the electrical effects of sensors in an empty condition and their interconnecting cables, at a time when the sensors are full or partially filled. By a sequential balancing technique, using a conventional bridge circuit, a precision, highly stable variable impedance device is adjusted to individually simulate the effects of each sensor and cable combination with the sensor in an empty condition. The settings of the variable impedance device are recorded, and at a later time when the sensors are no longer empty, these settings are reproduced, so as to recreate the electrical effects of each sensor cable combination one at a time. The individual effects are separately transferred into a network having a plurality of variable impedance channels, until each channel simulates the effects of a corresponding sensor and cable. This allows all of the earlier characterized effects to be simultaneously imposed on the measurement system.

대표청구항 ▼

Apparatus for calibrating a measurement system of the type having a plurality of measurement sensors, a control unit and a plurality of cables, each of said cables interconnecting one of said sensors to said control unit, and wherein the combination of a sensor and its associated cable has an effect

Apparatus for calibrating a measurement system of the type having a plurality of measurement sensors, a control unit and a plurality of cables, each of said cables interconnecting one of said sensors to said control unit, and wherein the combination of a sensor and its associated cable has an effect on the measurements made by said system, said apparatus comprising: a plurality of information transfer channels, there being at least one such channel for each sensor and cable combination; means for individually simulating the effect on said measurement system of each combination of a sensor in a predetermined condition and its associated cable; means for transferring the individually simulated effects of all said sensor and cable combinations into respective ones of said plurality of information transfer channels; and means for interconnecting said plurality of information transfer channels to said control unit, in place of said plurality of sensors and plurality of cables, whereby the effects of all said sensors in said predetermined condition and their associated cables are simultaneously imposed on said measurement system.