JPH03138551A - Humidity measuring instrument - Google Patents

Abstract

PURPOSE:To provide a detector itself with a function which outputs the quantity of deterioration and to eliminate the need for calibration using special equipment by calculating the continuance of the dew condensation state of a humidity detecting element as the quantity of dew condensation and deciding the deterioration from the cumulative value. CONSTITUTION:The subject instrument is constituted of the humidity detecting element 1, an A/D converter 2 which converts the output signal into a digital signal, a temperature detecting element 3, an A/D converter 4 which converts its output signal into a digital signal, a CPU 5 which inputs those digital signals, a timer 6, a memory part 7, and a display part 8. Then when it is decided whether measured humidity corresponds to the dew condensation state or not and the dew condensation state is discriminated, the continuance of the dew condensation is measured. Then the quantity of the change with the lapse of time corresponding to the dew condensation time is calculated, and cumulated and stored, and the cumulative stored value is outputted as the quantity of deterioration. Namely, when the cumulative stored quantity is large, it is known that the deterioration of the humidity detecting element 1 due to the dew condensation is advanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a humidity measuring device, and particularly to a humidity measuring device capable of outputting the amount of deterioration of a humidity detecting element.

(b) Conventional technology In general, resistance-type or capacitance-type temperature sensors are used as sensors (elements) in humidity measuring devices, and output signals according to resistance or capacitance values that change depending on humidity. Humidity is measured based on the signal.

However, in this type of humidity sensor, if the moisture sensitive membrane part becomes dew condensed and continues for a long period of time, conductive carriers decrease when dew condensed water flows out, causing a sudden change in characteristics and increasing measurement errors. Therefore, in the past, calibration was performed periodically using a humidity generation tank and a hygrometer for calibration, and if the measurement error was extremely large, the element was assumed to be deteriorated and replaced.

(c) Problems to be Solved by the Invention Conventional humidity measuring devices do not have a function to detect deterioration of the humidity detecting element, so as described above, a humidity generating tank and a hygrometer for calibration are used. Calibration had to be done periodically. Therefore, it is necessary to prepare equipment for calibration, and the calibration must be performed periodically, which is complicated.

Furthermore, there is a problem in that if the element deteriorates between calibrations and the next calibration, measurement errors occur during that period.

This invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a humidity measuring device which has a function of outputting the amount of deterioration in the detection device itself and does not require calibration using special equipment. It is an object.

(d) Means and operation for solving the problems The humidity measuring device of the present invention includes a humidity detecting element, a means for measuring humidity based on the output of the humidity detecting element, and a means for determining whether or not there is condensation. a means for measuring the dew condensation time from when it is determined that there is condensation to when it is determined that there is no condensation; a means that calculates the amount of change over time according to the measured time of dew condensation; and a means for accumulating the amount of change over time. It consists of a storage means and a means for outputting the cumulative storage amount as the amount of deterioration of the humidity detection element.

In this humidity measuring device, for example, it is determined whether or not there is condensation based on the humidity measured by the humidity measuring means, and if it is determined that there is condensation, the time from the occurrence of the condensation to the end of the condensation is measured. . Then, the amount of change over time is calculated according to this dew condensation time, and this amount of change over time is stored cumulatively.
This cumulative storage amount is output as the amount of deterioration. The longer the dew condensation time is, the more the deterioration progresses, and the cumulative value becomes larger. Therefore, if the amount of deterioration, that is, the cumulative amount of memory, is large, it is known that the deterioration of the humidity detection element due to dew condensation is progressing. Can be done.

(B) Examples The present invention will now be explained in more detail with reference to Examples.

FIG. 1 is a block diagram showing the hardware configuration of a humidity measuring device in which the present invention is implemented. This humidity measuring device includes a humidity detecting element 1, an A/D converter 2 that converts an output signal of the humidity detecting element 1 into a digital signal, and a temperature detecting element 3.
, an A/D converter 4 that converts the output signal of the temperature detection element 3 into a digital signal, a CPU 5 that takes in the digital signal from the A/D converter 2.4, a timer 6, and a memory section 7. It is composed of a display section 8.

As the humidity detection element 1, for example, a resistance type temperature sensor is used. The CPU 5 uses the output signal of the humidity detection element 1 taken in via the A/D converter 2 and the output signal of the temperature detection element 3 taken in via the A/D converter 4 to generate a temperature-compensated humidity signal. It has a function to measure.

In a humidity sensor, if the continuous duration of a dew condensation state is defined as the amount of dew condensation, the amount of dew condensation becomes a type of stress and accelerates the progress of deterioration. In addition, the humidity sensor detects high temperatures, high temperatures [approximately 40
°C or higher and 90% RH (relative humidity) or higher], the progress of deterioration is accelerated. Therefore, this example device has a function to determine the occurrence of dew condensation, measure the duration, and output the accumulated amount as the amount of deterioration, as well as a function to detect high temperature and high temperature state, and to accumulate the time at high temperature and high temperature. It has a function to output the cumulative value as the amount of deterioration. These two deterioration detection processes are executed by the CPU 5, and the data used during the execution is stored in the memory unit 7.

Although this embodiment has two deterioration detection processing functions: detection of dew condensation amount deterioration and high temperature/high temperature deterioration detection, it is possible to sufficiently detect deterioration of the humidity sensor with only one of the processes.

The CPU 5 has a function of outputting and displaying a sensor error signal on the display unit 8 when the cumulative value exceeds a predetermined value in any of dew condensation amount deterioration detection, high temperature, and high temperature deterioration detection.

As the dew condensation time t, (min (minutes)) increases beyond 44 m1, the stress increases accordingly, so the relationship between the dew condensation time tq and the stress amount α6 is shown in Figure 3. A table is stored in the memory section 7. In this table, K, <K2, . . . , <K, l, and accordingly α8.

Note that the method of calculating the deterioration conversion amount (stress amount) from the amount of dew condensation is estimated based on the temporal characteristics (actual measurement data) of the relationship between the number of dew condensation times of the humidity detection element, the dew condensation time, and the amount of change over time (deterioration amount).

In addition, in a high temperature state (for example, 90% RH or higher), the stress increases as the high temperature state continues, so a table showing the relationship between the element temperature information TX ('C) and the stress amount α1 as shown in Fig. 4 is prepared. It is stored in the memory section 7. In this table, the temperature is T+ <Tz <-<T(n4
)<Tn, and accordingly the stress amount α is also α1. <α1
□Ku...KuαA,,.

Next, with reference to the flowcharts shown in FIGS. 2(a) and 2(b), the deterioration detection processing operation of the humidity measuring device of the above embodiment will be described.

<High temperature/high humidity deterioration detection> The deterioration detection process execution cycle is tp=1mtn, and l
Every min, the determination of "processing timing" in step ST (hereinafter abbreviated as ST) becomes YES, and then it is determined whether the measured humidity I (.) is 95% RH or more (Sr1). Humidity HX is 95% If it is not RH, the judgment will be No and Sr1
Move to. If the humidity HX is 95%RH or more, the determination of Sr1 is YES and the process moves to 5TI3. 5T13 and subsequent steps are frost amount deterioration detection processing, which will be described later.

When Sr1 is used and no condensation occurs, the flag FP is set.
-0, that is, the judgment of "Frost formation amount detection processing completed" is NO, and the process moves to Sr1, from which high temperature and high humidity deterioration detection processing begins. First, the humidity HX measured in Sr1 is 90% RH. Determine whether or not the humidity is above 90.
If the temperature is not higher than %RH, it is assumed that the temperature is not high and the standard life stress setting is performed. i.e. the value α. α. and store it (Sr1). Next, what is stored as α is the stress amount α during the current tP.

and store it (Sr1). Further, the stress cumulative value RI stored in the memory unit 7 is successively stored, and is set as the stress cumulative value Σ5(n-1) up to the previous time (Sr1).

Next, the current stress amount α is added to the stress cumulative value ΣS (n-1) up to the previous time. is added to calculate the cumulative stress value ΣS (n) up to this time (Sr9). Then, this stress cumulative value ΣS (n) is stored as data D in the memory unit 7 (ST10), and the stress cumulative value ΣS (n) up to this time is compared with the deterioration judgment reference amount ΣS MAX, and ΣS ) It is determined whether IAX≦ΣS (n) (STII). If ΣS (n) has not reached ΣS i, ×, the current process ends with a NO determination in 5TII.

Then, when the next 1 min arrives, the ST
Execute the processing after I. Now, let αc-1 and Σ5HA
When setting X = 35040Hr, humidity H, is 9
If you continue measuring humidity for 4 years in a state where the RH is less than 0%RH, ΣS (n
) becomes 35040 hours, the judgment of 5TII becomes YES, sensor error processing is executed, and the LED of display unit 8
is lit. This notifies that the humidity detection element has deteriorated (ST12).

Humidity I(X
If measurement is continuously performed at 90% RH or higher, deterioration is determined at the earliest stage. Sr1 and 8.
If the determination of 290% RH is YES, the temperature is high, and in this case, from the measured temperature TX, the stress amount α
, is calculated. For example, if the temperature T is T2<TX<T3, the stress amount α is calculated from the memory unit 7 with reference to the table in FIG. is read out, and this stress amount αA3
is the current stress amount α. The current stress amount α0 (α.,) is added to the previous stress amount cumulative value ΣS (n-1) to calculate the current stress amount cumulative value ΣS (n). (Sr1.5T9
). Stress amount α. is set several times larger than the standard stress amount αゎ. Therefore, compared to accumulating αゎ during t2, if αゎ is accumulated every 1p, ΣS MAX This will be reached much earlier than four years, and sensor errors will be indicated sooner. Measured temperature T8 is 'ra <T, <'r
5, the corresponding stress amount is αA, and αA,
<αA, so the cumulative value ΣS (n) is ΣS ,4
It will reach AX even faster. In this way, in this embodiment, the longer the high humidity and high temperature conditions continue, the greater the amount of deterioration is output, and the earlier it is determined that the humidity detection element has deteriorated.

<Detection of deterioration in amount of dew condensation> If the measured humidity HX is 95% RH or more, it is determined here that there is dew condensation. Dew condensation is determined by:
The measured humidity HX may be set to an appropriate value between 95% and 100% RH, but the reason why it is set to 95% is that the measurement accuracy at an ambient temperature of 25°C is ±5% RH, and the difference of 5% RH is This is because when compared in terms of temperature, this corresponds to a variation of about 0.5°C, and this value can be judged to be sufficiently small considering the stability of the control environment.

If the determination of ``IHX≧95%RH or °'' is YES in Sr1, it means that a dew condensation state has occurred, and the process moves to 5T13, where it is determined whether the flag Fp=1, that is, whether dew condensation amount deterioration detection processing is in progress. .At the beginning when the condensation state has been reached, this judgment is N.
o, and here the condensation retention time t9 should be reset to 5T.
14),Flag F,.

II II II and start deterioration of dew condensation (S
T15). Then, the condensation retention time t9 until then is t
, to calculate the condensation retention time tQ (1) up to this time (ST16). Next, the condensation retention time tQ (I
5T17), t
If q fn+≧4 min is not satisfied, the determination is No and stress due to dew condensation is not considered and the process moves to Sr1. 5TI7
If (, q (n)≧4 min), the LED segment for displaying a condensation alarm on the display unit 8 is lit to notify that the humidity detection element is in a condensation state (S718).
, move on to Sr1. While the measured humidity H, is 95%RH or higher, it is assumed that dew condensation continues.
, 5T1B, . . . are repeated, and the measurement of the dew condensation retention time t9 is continued. During this time, the stress amount due to the deterioration of the amount of dew condensation is not integrated.

Eventually, when the measured humidity HX becomes less than 95%RH,
That is, when the dew condensation state is interrupted, the determination of Sr1 becomes NO, and the process moves to Sr1. In Sr1, the flag Fp was ``1'' until then.
Since the dew condensation amount deterioration detection process is completed, the determination of "°°" is YES, and the flag Fp is set to "0" (5T19), and the dew condensation holding time L Q (11-11> 4
5T20), jQ(n-11
If it is less than 4 min, ignore the condensation condition and
Jump to r1.

At 5T20, the dew condensation amount retention time jQ (n-11 is 4 min
If it exceeds the 3rd level, it is considered that there is stress due to the amount of dew condensation.
With reference to the stress amount selection table in the memory section 7 shown in the figure, read out the stress amount α corresponding to the dew condensation amount holding time tq (5T21), and use this stress amount α8 as the stress amount α for addition. Close it and memorize it. Stress amount α shown in Figure 3
4, α8□, . . . 1 αB0 is a large value on the order of Hr (time).

For example, if the condensation retention time is 1, the stress α
B4 is α. It is stored together (ST22). And S
Proceeding to r8, the cumulative stress amount DM up to that point is read out from the memory section 7, and the cumulative stress amount ΣS up to that point is read out from the memory unit 7.
(n-1), and this stress amount ΣS (n
−1), stress amount α. (αB4) to calculate the current cumulative stress amount ΣS (n) (5T9), and store this ΣS (n) in the memory section 7.

(STIO) On the other hand, the deterioration judgment reference amount ΣS
Compare WAX and stress cumulative value ΣS (n),
If MAX<ΣS (n), it waits until the next processing timing arrives after t has elapsed, but ΣSM□〈
In the case of ΣS (n), the sensor error LED on the display section 8
lights up to notify you that it is time to consider that the humidity detection element has deteriorated.

As the dew condensation time increases (tqKani+, Kg, K3, etc.), the amount of stress increases extremely, so the accumulation of deterioration is greatly accelerated, and the lifespan ends much earlier than the standard lifespan of 4 years. has arrived, and can be accurately announced.

In the above embodiment, in order to obtain the stress amount corresponding to the dew condensation time in the dew condensation state, the relationship between the dew condensation time and the stress amount is created in a table and stored in the memory section.
Alternatively, an approximation formula showing the relationship between dew condensation time and stress amount may be stored, and the stress amount may be calculated by applying the measured dew condensation time to this approximation formula.

(F) Effects of the Invention According to this invention, the continuous duration of the condensation state of the humidity detection element is calculated as the amount of dew condensation, the amount of deterioration converted from the calculated amount of dew condensation is accumulated, and the deterioration is determined from this cumulative value. Therefore, the deterioration can be grasped quantitatively, the deterioration of the humidity detection element can be notified by oneself without using a special instrument, and the humidity detection element can be replaced as early as possible.
Humidity measurement can always be performed with small measurement errors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the hardware configuration of a humidity measuring device in which the present invention is implemented; FIG. 2(a), FIG. 2(1))
3 is a flowchart for explaining the deterioration detection processing operation of the humidity measuring device, FIG. 3 is a table diagram showing the correspondence between dew condensation time and stress amount stored in the memory section of the humidity measuring device, and FIG. The figure is a table diagram showing the correspondence between element temperature information and stress amount stored in the memory section of the humidity measuring device. 1: Humidity detection element, 3: Temperature detection element, 5: CPU,
6F timer, 7: Memory section, 8: Display section.

Claims (1)

[Claims] (1) A humidity detection element, a means for measuring humidity based on the output of the humidity detection element, a means for determining whether there is condensation, and a means for determining whether there is condensation or not. means for measuring the dew condensation time, means for calculating the amount of change over time according to the measured time for dew condensation, means for cumulatively storing the amount of change over time, and the cumulative amount of storage as the amount of deterioration of the humidity detection element. A humidity measuring device comprising: a means for outputting an output.