JPH1123512A - Measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make accurate calibration by installing a sensor with a memory means storing the date of production and the change data of sensitivity after lapse of time, calculating the period after production with a control means, and making a calibrating action based on the change data after lapse of time. SOLUTION: This measuring device is provided with a calibrating circuit 22 making span adjustment and zero-point adjustment and a display driving means 23. A control means 26 reads the data of the nonvolatile writable memory of a sensor and a calibration data memory means 25 via an interface 24 based on the command of a control panel 2 and control the inspection of the compatibility of the sensor and a calibrating action. When the shipped sensor is delivered to an end user and the gas sensor is replaced, whether it is a compatible sensor or not is judged. When the compatible sensor is installed, the elapsed period after production is calculated based on the date of production in the nonvolatile writable memory and the built-in clock of the gas measuring device, the initial value of a sensor cell is calculated based on the elapsed period and the change data after the lapse of time, and the initial value is used as calibration data for calibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring apparatus using a sensor which is detachable and has a storage means for storing sensor information.

[0002]

2. Description of the Related Art For example, to measure gas, an opening of a container is sealed with an electrode plate in which an electrode material such as platinum black is formed in a layer on a diaphragm having water repellency and gas permeability. An electrochemical gas sensor configured to contain an electrolytic solution such as dilute sulfuric acid in a cell, a semiconductor gas sensor that changes electrical characteristics in response to gas, and the like are used.

[0003] Since a gas measuring device using such a sensor generates a detection signal in response to a gas, it has a shorter life than other types of sensors for detecting temperature and displacement. Requires a short replacement.

However, since the sensor has a very similar configuration in appearance, it is easily misidentified, and in order to prevent this, a gas for detecting the shape of a plug or socket for making contact with the apparatus body is used. Therefore, it is necessary to take a countermeasure such as making the difference slightly depending on the type of the device, and there is a problem that the number of parts is increased and the cost is increased.

In order to solve such a problem, a memory in which data such as a gas to be detected and a manufacturing date is recorded is mounted on a sensor, and data in the memory is read out from the main body of the measuring apparatus.
Measuring devices for determining whether a mounted sensor is appropriate have been put to practical use.

It has also been proposed to further store the data relating to the initial sensitivity of each sensor to support the adjustment of the zero point and the span of the measuring apparatus main body.

[0007]

According to such a technique, not only is it possible to prevent erroneous detection due to incorrect mounting of the sensor, but also it is possible to correct variations in the sensor by the main unit, and to use the sensor. The allowable range of the sensor can be expanded, and the cost can be reduced. However, since the gas sensor generates a detection output based on the reaction with the test gas, the sensitivity of the gas sensor in the unused state changes over time in comparison with a sensor for detecting a physical quantity, such as a temperature sensor. Has the problem of causing a decline in

The present invention has been made in view of such a problem, and an object of the present invention is to consider a change with time during a storage period, and to provide a method of mounting the same in a measuring device,
An object of the present invention is to provide a measuring device capable of accurately performing initial settings.

[0009]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a detachable sensor having storage means for storing data relating to the date of manufacture and a change with time in sensitivity, and the sensor. At the stage when is mounted, a control means for calculating a post-manufacturing period based on the data in the storage means and performing a calibration operation based on the data relating to the change with time is provided.

[0010]

According to the present invention, the output characteristics of the sensor are estimated based on the elapsed time after manufacture, and the measuring device is calibrated based on the estimated output characteristics.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention, in which a measuring device is provided with a display 1 for displaying a measurement result and control information described later, a control switch, and a control panel 2 such as a numeric keypad. On one side of the case 3, a window 5 from which the sensor 4 can be attached and detached is formed, and a socket 6 corresponding to the plug 13 of the sensor 4 is provided.

FIGS. 2 (a) and 2 (b) show an embodiment of the sensor 4 used in the above-mentioned measuring device, respectively.
0, the sensor cell 12 on the opening side,
In this embodiment, an electrochemical gas sensor cell is provided, a plug 13 is disposed on the rear end side, and a signal processing circuit 14 for performing analog processing on a signal of the cell 12 in a central portion, and an electrical storage circuit for storing sensor data described later. A non-volatile rewritable memory 15 such as an EEPROM or an interface means 16
Are mounted and accommodated on the circuit board 17.

With such a configuration, output signals from the electrodes 18 and 19 of the sensor cell 12 are subjected to predetermined processing by the signal processing circuit 14 and then output to the terminal of the plug 13.
The non-volatile rewritable memory 15 is read by the measuring device via the interface means 16.

The non-volatile rewritable memory 15 is provided in FIG.
As shown in the above, the sensor type, serial number, manufacturing date, detection target gas, full scale value, sensor output per unit concentration, aging characteristics, calibration characteristics, validity period, history, And maintenance data. The data of the aging characteristic is configured by digitizing data on the relationship between the period after shipment and the output value as shown in FIG. 4 or as a function. On the other hand, in the case of a sensor having a characteristic between the concentration of the gas to be detected and the output value which is not constant depending on the production lot or the like and showing a plurality of characteristics, a typical output characteristic indicated by these sensors is stored in a calibration data storage means 26 described later. A plurality of curves A, B, and C (FIG. 5) are stored in advance, and the data of the calibration characteristic is configured as data for specifying one of them.

Further, the history data is configured as data such as the date and time of an inspection performed for quality control before shipment, and the maintenance information is configured by voltage and current values to be set when using the sensor. Have been.

FIG. 6 shows an embodiment of the above-mentioned gas measuring device, which comprises a power supply means 20 for supplying driving power to the sensor, and a measuring signal of the sensor which is received via a preamplifier 21. A calibration circuit 22 that performs span adjustment and zero point adjustment under the control of a control unit 26 described later, a display driving unit 23 that displays measured values and control information on the display 1, The data in the nonvolatile rewritable memory 16 of the sensor 4 and the calibration data storage means 26 are read out via the interface 24 based on the interface 24, and the control means 26 controls the calibration of the sensor 4 and the inspection of the sensor compatibility. It is configured.

Next, the operation of the apparatus thus constructed will be described with reference to FIG.
A description will be given based on the flowchart shown in FIG. After production,
The sensor 4 is inspected as necessary, and at least the inspection date and its characteristics are stored in the nonvolatile rewritable memory 16 as history data.

Preferably, the data of full scale, change with time, and calibration characteristics are also updated, and more accurate data is stored in the nonvolatile rewritable memory 16. By repeating such work a plurality of times using the period until shipment, the subsequent characteristics of the sensor can be predicted. Therefore, caution must be taken based on data accumulated from accumulated research materials. If the items and the like are stored in the nonvolatile rewritable memory 16 as maintenance data, maintenance work can be supported.

When the sensor shipped through such a process is transferred to the end user's hand and the gas sensor 4 is replaced (step b), the data in the nonvolatile rewritable memory 16 built in the gas sensor 4 is read ( Step b), whether the sensor is within the warranty period is determined based on the sensor type data and whether the sensor is within the warranty period based on the data of the manufacturing date and the validity period. Is judged (Step c), and if not, a warning message stating "Sensor does not conform" is displayed on the display unit 1 (Step d), and the user is prompted for confirmation or replacement.

If necessary, the maintenance data stored in the non-volatile rewritable memory 16 is read out, and parameters to be set in the measuring apparatus main body, for example, the operating voltage and current supplied to the sensor are changed. By storing the maintenance data in this way, even if the specifications of the sensor are freely changed within a certain range in order to improve the characteristics of the sensor,
It can be easily handled on the measurement device side.

When the compatible sensor 4 is mounted in this way, the elapsed time after the manufacture of the sensor is determined by the date of manufacture of the nonvolatile rewritable memory 15 and the current date by the built-in clock of the gas measuring device. Then, the initial value of the sensor cell 12 is calculated based on the elapsed time and the data of the change with time, and calibration is performed using the initial value as calibration data (step E).

When the calibration characteristic data is stored in the non-volatile rewritable memory 15 (step F), a plurality of linearity data A and B stored in the correction data storage means 26 based on the data is stored. , C is selected and set for measurement (step). As described above, a plurality of data relating to the linearity of the sensor 4 is prepared in advance in the measuring apparatus main body side, and the data can be selected by the data in the nonvolatile rewritable memory 16 of the sensor 4. Not only can cost be reduced and measurement accuracy can be improved, but also erroneous purchase can be prevented.

Further, a plurality of calibration characteristics having a relatively large data amount are prepared in the measuring device, and the sensor 4 stores only data for specifying these calibration characteristics.
The storage capacity of the nonvolatile rewritable memory 16 built in the sensor, which is a consumable, can be significantly reduced, and the cost of the sensor 4 can be reduced.

When such preparation is completed, measurement becomes possible (step). During the measurement period, each time the calibration command button is operated, or every time a certain period of time, for example, one month has elapsed (step nu), the control means 26 reads the relevant sensor stored in the nonvolatile rewritable memory 15 of the sensor 4. The data of the change over time is read out, the period after manufacture is calculated from the date of manufacture and the current date, and the span and zero point are calibrated (step).

In principle, even in the case of a sensor cell which changes over time, the calibration operation using actual gas is not required, and the measuring device can be timely measured based on the data on the sensor accumulated in the manufacturing company. Calibration can be performed.

In the above-described embodiment, an explanation has been given by taking an example of an electrochemical gas sensor. However, a sensor whose output characteristics change with the lapse of time after manufacture, or which exhibits a large variation in linearity, for example, Obviously, the same effect is obtained even when applied to a semiconductor gas sensor.

[0027]

As described above, in the present invention,
A detachable sensor having a storage unit storing data on the date of manufacture, and the change over time of the sensitivity; and, at a stage where the sensor is mounted, calculating a period after manufacture based on the date of manufacture of the storage unit. And control means for performing a calibration operation based on data relating to aging, so that a current output value can be obtained based on an elapsed period after manufacturing, and accurate calibration considering aging can be performed. .

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing one embodiment of a measuring device of the present invention.

FIGS. 2A and 2B are a perspective view and a sectional view, respectively, showing an embodiment of a sensor.

FIG. 3 is a diagram showing data stored in a nonvolatile rewritable memory.

FIG. 4 is a diagram showing a temporal characteristic of a sensor stored in a nonvolatile rewritable memory.

FIG. 5 is a diagram illustrating an example of linearity of a sensor.

FIG. 6 is a block diagram showing one embodiment of the measuring device of the present invention.

FIG. 7 is a flowchart showing the operation of the above device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Display 2 Control panel 4 Sensor 6 Socket 11 Sensor case 12 Sensor cell 13 Plug 15 Non-volatile rewritable memory 17 Circuit board for sensors

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI G01N 27/12 G01D 3/02 N

Claims (4)

[Claims] 1. A detachable sensor having storage means for storing data relating to a manufacturing date and a change in sensitivity over time, and based on the manufacturing date of the storage means when the sensor is mounted. And a control means for performing a calibration operation on the basis of the data on the time-dependent change. 2. A calibration data storage means for storing a plurality of calibration characteristic data for defining linearity of the sensor group, wherein data for specifying the calibration curve data is stored in the storage means of the sensor. Item 2. The measuring device according to Item 1. 3. The measuring apparatus according to claim 1, wherein the storage means of the sensor is constituted by a rewritable nonvolatile memory. 4. The measuring apparatus according to claim 1, wherein the storage means of the sensor stores an inspection history and maintenance data.