JP2017075888A - Humidity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suitable quantity of heat to a humidity sensor element according to the amount of sorbed substances when thermally cleaning the humidity sensor element.SOLUTION: A thermal cleaning part 17C monitors the transitions of the element temperature T and the element measurement value C of the humidity sensor element 14 after a heater 16 starts heating a humidity sensor element 14. If it is confirmed that the element measurement value C has arrived in a predetermined allowable range Ca where the element measurement value C exhibits recovery of performance of sensing humidity, at the point of arrival confirmed when the element temperature T stops rising and then starts rising again, the heater 16 stops heating.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a humidity measurement technique, and more particularly to a heat cleaning technique for cleaning a moisture sensitive element having a moisture sensitive film by heating.

  As a general humidity sensor, there is a humidity sensor that has a humidity sensing element whose element measurement value changes due to moisture contained in the moisture sensitive film, and measures ambient humidity based on the element measurement value detected from the moisture sensing element. . Since such a humidity sensor is directly exposed to the atmosphere of the measurement environment and measures humidity, gas such as moisture and chemicals / solutions in the atmosphere are sorbed to the humidity sensing element. For this reason, an error between the element measurement value of the moisture sensitive element and the initial element measurement value becomes large, and as a result, the measurement accuracy of the moisture sensitive element is lowered and further the humidity sensitive element is deteriorated.

  Conventionally, as a method of recovering such deterioration of the moisture sensitive element, a moisture sensitive element is provided by heating the moisture sensitive element by periodically driving the heater during periods other than humidity measurement. A technique has been proposed in which heat cleaning is performed to remove sorbents contained in the moisture and the deterioration of the moisture sensitive element is determined based on the difference between the measured value of the moisture sensitive element measured after the implementation and the initial value. (Refer to patent document 1 etc.). Accordingly, it is possible to suppress the progress of deterioration of the moisture sensitive element and to accurately determine whether or not the humidity sensitive element needs to be replaced due to the progress of deterioration.

Japanese Patent No. 5216442

In such a humidity sensor of the humidity sensor, there is a trade-off between the measurement accuracy recovery and the measurement life for heating cleaning, and therefore appropriate heating according to the amount of the sorbent is desirable during the heating cleaning. For example, when the amount of sorbed material is large, it is necessary to apply a sufficient amount of heat to the moisture-sensitive element, but when the amount of sorbed material is small, it is necessary to suppress the excessive amount of heat from being applied.
However, in the above-described conventional technology, when the moisture sensitive element is periodically heated and cleaned, the heater is driven only for a predetermined time regardless of the amount of the sorbed material. There was a problem that it was not possible to give a sufficient amount of heat.

  The present invention is to solve such problems, and provides a heating cleaning technique capable of giving an appropriate amount of heat to the moisture sensitive element according to the amount of the sorbent when the moisture sensitive element is heated and cleaned. The purpose is that.

  In order to achieve such an object, the humidity sensor according to the present invention has a humidity sensing element whose element measurement value changes according to humidity, and is based on the element measurement value detected from the humidity sensing element. A humidity sensor for measuring humidity in an atmosphere, wherein a heater that desorbs a sorbent adsorbed on the moisture sensitive element by heating the moisture sensitive element, and heating of the moisture sensitive element by the heater After the start, the transition of the element temperature and the element measurement value of the humidity sensitive element is monitored, and when the increase in the element temperature is stopped, the element measurement value indicates a recovery of the moisture sensitive performance. And a heating cleaning unit that stops heating by the heater when it is confirmed that it has reached the inside.

  Also, in one configuration example of the humidity sensor according to the present invention, the heating cleaning unit heats the moisture sensitive element with the heater after the arrival confirmation time, and the element temperature rises from the arrival confirmation time. According to the presence / absence, the presence / absence of deterioration of the moisture sensitive element in relation to the moisture sensitive performance is diagnosed.

  Also, in one configuration example of the humidity sensor according to the present invention, when the element temperature rises by the deterioration diagnosis temperature range before the predetermined determination time elapses from the arrival confirmation time, the heating cleaning unit It is diagnosed that there is no deterioration of the moisture sensitive performance, and if the element temperature does not increase by the degradation diagnostic temperature range even after the determination time has elapsed, it is diagnosed that the moisture sensitive performance is degraded.

  In addition, in one configuration example of the humidity sensor according to the present invention, the heater may be used when the element temperature of the moisture sensitive element rises from an upper limit temperature while the heat cleaning unit is heating the moisture sensitive element with the heater. The heating by is stopped.

  Further, in one configuration example of the humidity sensor according to the present invention, the heating cleaning unit is heating the moisture sensitive element with the heater, and when the element measurement value of the moisture sensitive element exceeds a limit value, Heating by the heater is stopped.

  In addition, another humidity sensor according to the present invention has a humidity sensing element whose element measurement value changes according to the humidity, and measures humidity in the measurement environment atmosphere based on the element measurement value detected from the humidity sensing element. A humidity sensor that heats the moisture sensitive element to desorb a sorbent adsorbed on the moisture sensitive element; and after the heater starts heating the moisture sensitive element, Monitor the transition of the element temperature and the element measurement value of the moisture sensitive element, and when the increase in the element temperature has stopped, the element measurement value has reached the predetermined tolerance range indicating the recovery of the moisture sensitivity performance. A heating cleaning unit that continues heating by the heater at the confirmed arrival confirmation time, and diagnoses the presence or absence of deterioration of the moisture sensitive performance of the moisture sensitive element according to whether the element temperature has increased from the arrival confirmation time; It has.

  In addition, another humidity sensor according to the present invention has a humidity sensing element whose element measurement value changes according to the humidity, and measures humidity in the measurement environment atmosphere based on the element measurement value detected from the humidity sensing element. A humidity sensor that heats the moisture sensitive element to desorb a sorbent adsorbed on the moisture sensitive element; and after the heater starts heating the moisture sensitive element, And a heating cleaning unit that monitors a decrease in the element measurement value of the moisture sensitive element and stops heating by the heater when the element measurement value exceeds a limit value.

  According to the present invention, when the moisture sensitive element is heated and cleaned, the heating stop timing is adjusted according to the amount of the sorbed material, rather than being heated by the heater for a predetermined period of time. The amount of heat can be applied to the moisture sensitive element. Therefore, it is possible to suppress the occurrence of measurement errors due to the shortage of heat to be applied, and to avoid deterioration due to excessive heat.

It is a block diagram which shows the structure of a humidity sensor. It is an example of 1 structure of a moisture sensitive element. It is a flowchart which shows the heat cleaning process with respect to a moisture sensitive element. It is a graph which shows the example of a change of the element measurement value and element temperature in heat cleaning.

[Principle of the Invention]
As described above, when the sorbent sorbs on the moisture sensitive film of the moisture sensitive element, the error between the element measured value of the moisture sensitive element and the initial element measured value increases, resulting in a decrease in the measurement accuracy of the moisture sensitive element. Furthermore, it causes deterioration of the moisture sensitive element. In the present invention, the element measurement value of the moisture sensitive element tends to increase as the sorbent increases, and the element measurement value corresponds to the detachment of the sorbent due to heating of the moisture sensitive element. It is noted that there is a tendency to decrease toward the initial element measurement value and stop.

  Based on such a tendency, a predetermined allowable range indicating the recovery of moisture sensitivity performance is set in advance with reference to the initial element measurement value, and heating of the moisture sensitive element by the heater is started. When it is confirmed that the measured value of the element has reached a predetermined allowable range indicating the recovery of moisture-sensitive performance at the time of arrival confirmation when the rise starts again after stopping the rise, the desorption of the sorbent is completed. Thus, it is assumed that the moisture sensitive performance has been recovered, and heating of the moisture sensitive element by the heater is stopped. Accordingly, when the moisture sensitive element is heated and cleaned, an appropriate amount of heat can be given to the moisture sensitive element without excess or deficiency depending on the amount of the sorbent.

[Humidity sensor]
Next, an embodiment of the present invention will be described with reference to the drawings.
First, a humidity sensor 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the humidity sensor.

  This humidity sensor 10 has a humidity sensitive element whose element measurement value changes due to moisture contained in the moisture sensitive film, and has a function of measuring ambient humidity based on the element measurement value detected from the moisture sensitive element. Yes. For example, the humidity sensor 10 is used when measuring humidity by being directly exposed to the atmosphere of a measurement environment in the manufacturing process of various articles. At this time, a gas composed of moisture, chemicals, and solutions in the atmosphere, for example, a gas of an organic solvent such as methanol, ethanol, propanol, and acetone, is sorbed on the moisture sensitive element. For this reason, it has a function of desorbing the sorbed material adsorbed on the moisture sensitive element by heating and cleaning the moisture sensitive element.

  The humidity sensor 10 includes a communication I / F unit 11, an operation input unit 12, a display unit 13, a humidity sensor 14, a temperature sensor 15, a heater 16, and a control unit 17 as main function units. . The communication I / F unit 11 performs data communication with an external device such as an industrial controller connected via a communication line, so that a setting instruction, a measurement instruction, a heating cleaning instruction, and a humidity measurement result regarding humidity measurement are performed. It has a function of exchanging various data such as deterioration diagnosis results.

The operation input unit 12 includes an operation input device such as a button or a switch, and has a function of detecting an operation of the operator and outputting the operation to the control unit 17.
The display unit 13 includes a display device such as an LCD or an LED, and has a function of displaying various data such as setting contents related to humidity measurement, a humidity measurement result, and a deterioration diagnosis result.

  The moisture sensitive element 14 is an element whose element measurement value (element capacitance value) C changes due to moisture contained in the moisture sensitive film. FIG. 2 is a configuration example of the moisture sensitive element, FIG. 2A is a top view of the moisture sensitive element, and FIG. 2B is a front view of the moisture sensitive element. In addition, FIG. 2 is one structural example of a moisture sensitive element, and is not limited to this structural example.

  The moisture sensitive element 14 includes a first detection electrode 14E formed on the surface of the substrate 14B and a moisture sensitive film made of a polymer material having a specific cross-linked structure formed on the upper surface of the detection electrode 14E. 14F and a second detection electrode 14E formed on the upper surface of the moisture sensitive film 14F. That is, the two detection electrodes 14E are opposed to each other with the moisture sensitive film 14F interposed therebetween. These detection electrodes 14E are connected to the control unit 17 via lead wires L1 connected to pads 14P formed at the respective end points, and the detection electrodes 14E that change according to the moisture contained in the moisture sensitive film 14F. The element measurement value C in between is detected by the humidity measuring unit 17A and converted into humidity.

  A temperature sensing element 15 made of a resistance temperature detector is disposed on the back surface of the substrate 14B opposite to the detection electrode 14E, and is connected to the control unit 17 via a lead wire L2 connected to the pad 15P. The resistance value of the resistance temperature detector that changes in accordance with the temperature is detected by the control unit 17 and converted into the element temperature T of the humidity sensing element 14. The temperature sensing element 15 operates as a heater 16 that generates heat by the drive current supplied from the control unit 17 via the lead wire L2, and heat-cleans the moisture sensitive film 14F of the humidity sensing element 14 by heat generation.

  The control unit 17 includes a control circuit having a CPU and its peripheral circuits, and has a function of controlling a humidity measurement operation and a heating cleaning operation in the humidity sensor 10. The control unit 17 is provided with a humidity measurement unit 17A, a temperature measurement unit 17B, and a heat cleaning unit 17C as main processing units.

  The humidity measuring unit 17A converts the element measurement value C of the moisture sensitive element 14 detected via the lead wire L1 into humidity based on a preset function equation, thereby surrounding humidity including the moisture sensitive element 14 And a measurement result is displayed and output on the display unit 13 or output to an external device via the communication I / F unit 11.

  The temperature measurement unit 17B measures the element temperature T of the moisture sensitive element 14 by converting the resistance value of the temperature sensitive element 15 detected via the lead wire L2 into a temperature based on a preset function equation. It has a function.

  The heat cleaning unit 17C has a function of driving the heater 16 to start heating of the moisture sensitive element 14 when the moisture sensitive element 14 is heated and cleaned, and an element temperature T and an element of the humidity sensitive element 14 after starting the heating. The function of monitoring the transition of the measurement value C and the arrival that the element measurement value C has reached the predetermined allowable range Ca indicating the recovery of the moisture sensitive performance when the increase in the element temperature T is stopped is confirmed. It has a function of stopping heating by the heater 16 at the time of confirmation.

  Further, the heat cleaning unit 17C has a function of heating the moisture sensitive element 14 by the heater 16 after the arrival confirmation time and the presence / absence of an increase in the element temperature T of the moisture sensitive element 14 from the arrival confirmation time. It has a function of diagnosing the presence or absence of deterioration related to moisture sensitive performance. More specifically, when the element temperature T rises by the deterioration diagnosis temperature width ΔT before a predetermined determination time has elapsed from the arrival confirmation time point, a function for diagnosing that there is no deterioration in moisture sensitivity performance, and from the arrival confirmation time point If the element temperature T does not increase by the deterioration diagnosis temperature range ΔT even after the determination time has elapsed, it has a function of diagnosing that there is a deterioration in moisture sensitive performance.

[Operation of this embodiment]
Next, the operation of the humidity sensor 10 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing a heat cleaning process for the moisture sensitive element.
The heat cleaning unit 17C of the control unit 17 performs the heat cleaning process of FIG. 3 periodically or in response to an instruction from the communication I / F unit 11 or the operation input unit 12.

First, the heating cleaning unit 17C drives the heater 16 to start heating the moisture sensitive element 14 (step 100), and measures the element temperature T by the temperature measurement unit 17B (step 101).
Here, the heat cleaning unit 17C checks whether or not the increase in the element temperature T has stopped (step 102).
Here, when it is confirmed that it has stopped (step 102: YES), the heating cleaning unit 17C monitors the transition of the element measurement value C sequentially measured by the humidity measurement unit 17A, and the element measurement value C When the measured value C falls within the predetermined allowable range Ca indicating the recovery of the moisture sensitive performance (step 103), it is not confirmed that the element measurement value C has reached the allowable range Ca (step 103). : NO), it returns to step 101.

On the other hand, when it is confirmed that the element measurement value C has reached the permissible range Ca (step 103: YES), the heat cleaning unit 17C detects the humidity-sensitive element 14 detected by the temperature-sensitive element 15 at the arrival confirmation time point. The element temperature T is stored as the reference temperature T0 (step 104), and it is confirmed whether or not the element temperature T is increased by the subsequent heating (step 105).
Here, when an increase in the element temperature T is confirmed (step 105: YES), when the element temperature T increases from the reference temperature T0 by a predetermined deterioration diagnosis temperature range ΔT, the heating of the moisture sensitive element 14 by the heater 16 is performed. Is stopped (step 106).

  Accordingly, after the element measurement value C reaches within the allowable range Ca, it can be confirmed that the element temperature T has risen and it can be determined that the moisture sensitivity of the moisture sensitive element 14 has been recovered. The sensor 14 is diagnosed as “sensor normal” indicating that the moisture sensitivity performance has not deteriorated, and the diagnosis result is output (step 107), and the series of heat cleaning processes is terminated.

  On the other hand, in step 105, if the increase in the element temperature T cannot be confirmed even after heating for a certain determination time after the arrival confirmation time point (step 105: NO), the element measurement value C has reached the allowable range Ca. Thereafter, the element temperature T does not rise, and it cannot be determined that the moisture sensitive performance of the moisture sensitive element 14 has been recovered. Therefore, the heating cleaning unit 17C stops the heating of the moisture sensitive element 14 by the heater 16 (step 109). A diagnosis of “sensor deterioration” indicating that the humidity sensing performance of the moisture sensing element 14 is degraded is output (step 110), and a series of heat cleaning processes is terminated.

If the element temperature T is not stopped at step 102 (step 102: NO), the heat cleaning unit 17C confirms whether the element temperature T is equal to or higher than a preset upper limit temperature Tlim (step 108). .
If the element temperature T is lower than the upper limit temperature Tlim (step 108: NO), the process returns to step 102. On the other hand, when the element temperature T rises by the upper limit temperature Tlim or more (step 108: YES), the heating cleaning unit 17C determines that it is abnormal and proceeds to step 109.

FIG. 4 is a graph showing an example of changes in the element measurement value and the element temperature in the heat cleaning. The characteristic 20 shows the change in the element temperature T, and the characteristic 21 shows the change in the element measurement value C.
It is assumed that the element measurement value C indicates the measurement value C3 and the element temperature T indicates the temperature T0 at the time t0 when the heat cleaning starts. In addition, it is assumed that a range from Cah to Cal centered on the initial element measurement value C0 is set as a possible range of the element measurement value C in the initial state without a sorbent, that is, an allowable range Ca.

As shown in FIG. 4, when the heating of the moisture sensitive element 14 by the heater 16 is started from the time t0, the element measurement value C is constant at C3 in the section A from the time t0 to the time t1, and only the element temperature T is obtained. Increases from T0 to T1, and in the section B from time t1 to time t2, the element temperature T is constant at T1, and only the element measurement value C decreases from C3 to C2.
Similarly, in the section C from time t2 to time t3, the element measurement value C is constant at C2, and only the element temperature T rises from T1 to T2, and in the section D from time t3 to time t4, the element temperature T is constant at T2, and only the element measurement value C decreases from C2 to C1.

In general, the sorbents that sorb on the moisture sensitive element 14 each have a unique desorption temperature, and desorption is not initiated until the temperature of the sorbent reaches the desorption temperature. In addition, the sorbent as referred to in the present invention includes not only a single substance but also a mixture or composite of a plurality of substances.
In FIG. 4, there are a section B and a section D as sections in which the element temperature T is constant, the temperature T1 in the section B corresponds to the desorption temperature of the sorbent X, and the temperature T2 in the section D is the sorbent Y. This corresponds to the desorption temperature.

  Therefore, in the section A, the element temperature T does not reach the desorption temperature T1, and the sorbents X and Y do not desorb, so most of the thermal energy due to heating is used for temperature rise. For this reason, only the element temperature T increases while the element measurement value C remains substantially constant. On the other hand, in the section B, since the element temperature T reaches the desorption temperature T1 and the desorption of the sorbent X proceeds, most of the thermal energy due to heating is used for desorption. For this reason, only the element measurement value C decreases while the element temperature T remains constant.

  Similarly, in the section C, since the element temperature T does not reach the desorption temperature T2 and the sorbent Y does not desorb, most of the heat energy by heating is used for temperature rise. For this reason, only the element temperature T increases while the element measurement value C remains substantially constant. On the other hand, in the section D, since the element temperature T reaches the desorption temperature T2 and desorption of the sorbent Y proceeds, most of the thermal energy by heating is used for desorption. For this reason, only the element measurement value C decreases while the element temperature T remains constant.

  Thus, when the desorption of the sorbents X and Y is completed at time t4, the once stopped element temperature T starts increasing again, and the element measurement value C decreases to within the allowable range Ca, It stops at the measured value C1. Therefore, by confirming this state, it can be seen that the desorption of the sorbents X and Y has been completed. Therefore, if the heating is stopped at this time t4, that is, when the arrival is confirmed, an excess or deficiency is caused depending on the amount of the sorbent. And an appropriate amount of heat can be given to the moisture sensitive element 14.

  In addition, when heating is continued in the section E after time t4, if no sorbent remains and the moisture sensitive performance of the moisture sensitive element 14 is recovered, the element measurement value C does not change. Only the element temperature T rises. On the other hand, when the sorbent remains and the moisture sensitive performance cannot be recovered, only the element measurement value C changes and the element temperature T does not rise. Therefore, the presence or absence of deterioration of the moisture sensitive element 14 can be diagnosed depending on whether or not the element temperature T rises by heating the moisture sensitive element 14 after time t4.

  In this case, a deterioration diagnosis temperature range ΔT is provided, and at time t5 when the moisture sensitive element 14 is heated after time t4 and increased from the element temperature T2 at time t4 by ΔT, it is diagnosed that the moisture sensitive element 14 is normal, If the temperature does not rise from the element temperature T2 by ΔT within a certain determination time from the time t4, it is diagnosed that the moisture sensitive element 14 is deteriorated.

  Therefore, when the humidity sensing element 14 is normal, the heating of the moisture sensing element 14 by the heater 16 is stopped at time t5, so that in the section F, the element temperature T gradually decreases from T3, and thereafter time t6. Return to the original T0. When the moisture sensitive element 14 is deteriorated, the heating of the moisture sensitive element 14 by the heater 16 is stopped after the determination time has elapsed from time t4.

  If the sorbent does not desorb even when the moisture sensitive element 14 is heated, the element temperature T gradually increases as shown by the characteristic 20A. Therefore, when the element temperature T rises above the upper limit temperature Tlim, the heating of the moisture sensitive element 14 by the heater 16 is stopped, so that excessive heating of the moisture sensitive element 14 is avoided, and the moisture sensitive element 14 deteriorates. Is diagnosed.

  In addition, when the element measurement value C has reached the allowable range Ca at the time when the element temperature has once started to rise again after the element temperature has stopped rising, it is determined that the desorption of the sorbent is complete, Although the case where heating of the moisture sensitive element 14 by the heater 16 is stopped as an example has been described, the limit value Clim is set in advance, and when the element measurement value C decreases and exceeds the limit value Clim, It may be determined that the desorption is completed, and the heating of the moisture sensitive element 14 by the heater 16 may be stopped.

In this case, as the limit value Clim, a value that can be reached by the element measurement value C may be selected as long as the deterioration state is within an allowable range, such as the upper limit value Cah of the allowable range Ca. Thereby, the completion of the heating cleaning can be determined by a simpler process than the determination algorithm described in FIG.
Further, as the limit value Clim, for example, a value that is lower than the lower limit value Cal of the allowable range Ca and that the element measurement value C cannot reach in a normal deterioration state may be selected. Thereby, it is possible to avoid that the element measurement value C decreases beyond the allowable range Ca due to a failure or the like and the heating by the heater 16 becomes excessive.

Further, in the present embodiment, as shown in FIG. 2, a capacitive humidity sensing element 14 that detects humidity based on a capacitance change between two sensing electrodes 14E that are opposed to each other with a moisture sensing film 14F interposed therebetween is used. However, the present invention can be similarly applied to a case where a resistance type humidity sensitive element that detects humidity based on a change in resistance value between the detection electrodes 14E is used.
At this time, as shown in FIG. 4, contrary to the element capacitance value C, the element resistance value R increases as the collection proceeds, but the heating cleaning determination method and the deterioration determination method are as follows. The same method as in the case of using the capacitance type moisture sensitive element 14 described above can be used.

[Effects of the present embodiment]
Thus, in the present embodiment, after the heating cleaning unit 17C starts heating the moisture sensitive element 14 by the heater 16, the transition of the element temperature T and the element measurement value C of the moisture sensitive element 14 is monitored, and the element The heating by the heater 16 is stopped at the arrival confirmation point when it is confirmed that the element measurement value C has reached the predetermined allowable range Ca indicating the recovery of the moisture sensitive performance when the increase in the temperature T is stopped. It is a thing.
As a result, when the moisture sensitive element 14 is heated and cleaned, the heating stop timing is adjusted according to the amount of the sorbed material, rather than being heated by the heater for a predetermined period of time. It can be applied to the moisture sensitive element 14. Therefore, it is possible to suppress the occurrence of measurement errors due to the shortage of heat to be applied, and to avoid deterioration due to excessive heat.

In the present embodiment, the moisture sensitive element 14 is heated by the heater 16 after the arrival confirmation time, and the moisture sensitivity of the moisture sensitive element is determined according to whether the element temperature T of the humidity sensitive element 14 has increased since the arrival confirmation time. It is designed to diagnose the presence or absence of deterioration related to performance. More specifically, if the element temperature T rises by the deterioration diagnosis temperature range ΔT before a predetermined determination time has elapsed from the arrival confirmation time point, it is diagnosed that there is no deterioration in moisture sensitive performance, and the determination time from the arrival confirmation time point If the element temperature T does not rise by the deterioration diagnosis temperature range ΔT even after the lapse of time, it is diagnosed that the moisture sensitive performance is deteriorated.
Accordingly, as described above, it is possible to determine whether or not the moisture sensitive element 14 is deteriorated without giving an excessive amount of heat, and it is possible to avoid the promotion of deterioration due to the excessive amount of heat.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In addition, each embodiment can be implemented in any combination within a consistent range.

  DESCRIPTION OF SYMBOLS 10 ... Humidity sensor, 11 ... Communication I / F part, 12 ... Operation input part, 13 ... Display part, 14 ... Humidity sensitive element, 14B ... Substrate, 14E ... Detection electrode, 14F ... Humidity sensitive film, 14P ... Pad, 15 ... temperature sensitive element, 15P ... pad, 16 ... heater, 17 ... control part, 17A ... humidity measuring part, 17B ... temperature measuring part, 17C ... heating cleaning part, L1, L2 ... lead wire, C ... element measured value, Ca ... tolerance, Clim ... limit value, T ... element temperature, Tlim ... upper limit temperature, ΔT ... deterioration diagnosis temperature range.

Claims (7)

A humidity sensor that has a humidity sensing element whose element measurement value changes according to humidity and measures humidity in a measurement environment atmosphere based on the element measurement value detected from the humidity sensing element,
A heater that desorbs the sorbent adsorbed on the moisture sensitive element by heating the moisture sensitive element;
After the heating of the moisture sensitive element is started by the heater, the transition of the element temperature and the element measurement value of the moisture sensitive element is monitored, and the element measurement value is detected when the increase in the element temperature is stopped. A humidity sensor comprising: a heating cleaning unit that stops heating by the heater when it is confirmed that it has reached a predetermined allowable range indicating recovery of performance. The humidity sensor according to claim 1,
The heating cleaning unit heats the moisture sensitive element with the heater after the arrival confirmation time, and deteriorates the moisture sensitivity performance of the moisture sensitive element according to whether or not the element temperature has increased from the arrival confirmation time. A humidity sensor characterized by diagnosing the presence or absence. The humidity sensor according to claim 2,
The heating cleaning unit diagnoses that the moisture sensitive performance is not deteriorated when the element temperature rises by a deterioration diagnosis temperature width before a predetermined determination time elapses from the arrival confirmation time, and the determination time elapses. However, if the element temperature does not increase by the degradation diagnosis temperature range, the humidity sensor is diagnosed as having degraded the moisture sensitive performance. In the humidity sensor according to any one of claims 1 to 3,
The heating cleaning unit stops heating by the heater when the element temperature of the moisture sensitive element rises from an upper limit temperature while heating the moisture sensitive element by the heater. In the humidity sensor according to any one of claims 1 to 4,
The heating cleaning unit stops heating by the heater when an element measurement value of the moisture sensitive element exceeds a limit value while heating the moisture sensitive element by the heater. A humidity sensor that has a humidity sensing element whose element measurement value changes according to humidity and measures humidity in a measurement environment atmosphere based on the element measurement value detected from the humidity sensing element,
A heater that desorbs the sorbent adsorbed on the moisture sensitive element by heating the moisture sensitive element;
After the heating of the moisture sensitive element is started by the heater, the transition of the element temperature and the element measurement value of the moisture sensitive element is monitored, and the element measurement value is detected when the increase in the element temperature is stopped. Heating by the heater is continued at an arrival confirmation point when it has been confirmed that it has reached a predetermined allowable range indicating performance recovery, and the moisture sensitivity is determined depending on whether or not the element temperature has increased since the arrival confirmation point. A humidity sensor comprising: a heating cleaning unit that diagnoses the presence or absence of deterioration related to the moisture-sensitive performance of the element. A humidity sensor that has a humidity sensing element whose element measurement value changes according to humidity and measures humidity in a measurement environment atmosphere based on the element measurement value detected from the humidity sensing element,
A heater that desorbs the sorbent adsorbed on the moisture sensitive element by heating the moisture sensitive element;
After the heating of the moisture sensitive element is started by the heater, the decrease in the element measurement value of the moisture sensitive element is monitored, and the heating by the heater is stopped when the element measurement value exceeds the limit value And a humidity sensor.