JPS6329251Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an automatic calibration device that is used as an auxiliary device for a continuous analyzer and automatically corrects the zero point drift and span drift of the analyzer using an appropriate reference quantity.

Conventional automatic calibration equipment repeatedly detects errors and performs auxiliary operations at regular intervals, and if drift continues for longer than the set interval, sufficient correction cannot be made, and even if the drift is slow, it cannot be automatically corrected. Since the calibration operation is performed at a fixed set period, the flow cell type analyzer has the disadvantage that the reference sample is wasted.

This invention aims to provide an automatic calibration device that eliminates the above-mentioned disadvantages, and this invention will be explained below with reference to an embodiment of the device shown in the drawings.

The figure is a block diagram of an automatic calibration device built into a continuous gas analyzer, where 1 is an analyzer and its output goes into a reference value comparator 2 of the automatic calibration device. The reference comparator 2 compares the output of the reference value setter 3 with the reference value set corresponding to the reference amount of zero point gas or span sample gas of known concentration introduced into the analyzer 1 for calibration. The output value from the analyzer 1 during calibration is compared, the difference or ratio is detected by the error detector 4, and the output of the analyzer 1 is corrected (calibrated) by the correction value output device 5 based on this detection signal. taken outside.

On the other hand, the error storage 6 stores the error value from the previous calibration, and the storage 7 stores the correction value from the current calibration. The difference between these two is detected by the error comparator 8, and the ratio between the value of this difference and the allowable value based on the accuracy of the analyzer is calculated, and the time interval (cycle) for the next calibration is calculated using the automatic calibration cycle calculator. Determined by 9. According to this determined calibration period, the signal generator 10 at the time of calibration
outputs the next calibration start signal for analyzer 1 and the automatic calibration system. In other words, in the case of a gas analyzer, the operation of the automatic calibration system is started upon introduction of a reference amount of sample gas for zero point or span calibration.

Analyzers generally perform correction using a digital method in order to perform highly accurate correction, and the above example stores the previous error signal value and the current error signal value, respectively. The calibration cycle is controlled based on the difference, but when correcting in an analog way, only the previous error signal value is memorized and the difference with the current error signal value is directly detected.
A calibration start command can be issued based on the integral value.

According to this idea, by automatically determining the calibration period, accuracy is maintained regardless of the magnitude of the analyzer's drift, and in the case of analyzers using flow cells, the calibration interval is automatically determined when the drift is small. This allows the calibration cycle to be extended and the consumption of reference samples to be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an automatic calibration device according to an embodiment of this invention. 1: Analyzer, 2: Reference value comparator, 3: Reference value setter, 4: Error detector, 5: Correction value output device, 6:
Error storage, 7: Storage, 8: Error comparator, 9:
Calibration cycle automatic calculator, 10: Calibration signal generator.

Claims (1)

[Scope of utility model registration request] A device that periodically switches to a reference amount of sample during measurement, detects an error between the output value at that time and a preset reference value, and periodically calibrates the measured output value according to the error. An error storage device that stores the error value, an error comparator that compares this stored value with the current error value, an arithmetic unit that determines the calibration period based on the output of this comparator, and a What is claimed is: 1. An automatic calibration device comprising means for issuing a next calibration command signal, and shortening or extending a calibration cycle depending on an error in a reference amount of a sample.