CN104977096A - Temperature characteristic correcting device of thermistor and temperature characteristic correcting method of thermistor - Google Patents
Temperature characteristic correcting device of thermistor and temperature characteristic correcting method of thermistor Download PDFInfo
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Abstract
A measurement circuit unit (2) is configured to selectively connect measurement circuits (21, 22, 23) with a thermistor (1). The measurement circuits (21, 22, 23) are configured to enable the voltage change corresponding to changes of the resistance value to have similar linear characteristics for different temperature ranges measured by the thermistor (1). A CPU (4) switches connection between the thermistor (1) and each measurement circuit (21, 22, 23) according to changes of the A/D transformation data value output by the measurement circuit unit (2), and can read the coefficient corresponding to the measurement circuits which are connected with the thermistor (1) from a flash memory device (6) to perform three times of approximation to function calculation to obtain the temperature corresponding to the A/D transformation data value; and according to the area defined by the threshold value of the output variation exported from the required output characteristic, the data after transformation can be output to form linear characteristics for each temperature.
Description
Technical field
The characteristic revision that the present invention relates to the data value exported according to the temperature detected by thermistor is linear apparatus and method.
Background technology
The characteristic of the voltage exported as the thermistor of detector unit is non-linear, is thus difficult to directly be used, therefore proposes various for output voltage characteristic is transformed to linear technology in the past.Such as, in patent documentation 1, the temperature range that thermistor can be detected-10 DEG C ~+80 DEG C be divided into 3 temperature ranges (-10 DEG C ~+20 DEG C ,+20 DEG C ~+50 DEG C, + 50 DEG C ~+80 DEG C), and utilize variable resistance circuit to distribute resistance value R1 different separately, R2, R3.Further, produce the resistance value corresponding with the segmentation temperature range belonging to the detected temperatures of thermistor, and in each temperature range, make the output voltage in temperature sensing circuit portion roughly change relative to the change of detected temperatures respectively direct proportion.
But, due in patent documentation 1, not about the clear and definite benchmark that the scope of each temperature range setting direct proportion change is used, although thus may exist is that the scope of direct proportion change is as the part be excluded beyond usable range.If there is the scope be excluded like this, then consequently, making the resistive element increasing number used to cover temperature range, for no reason increasing components number.
Prior art document
Patent documentation
Patent documentation 1: Japanese Unexamined Patent Publication 6-168387 publication
Summary of the invention
Present invention has been made in view of the above problem, its object is to provide a kind of temperature characterisitic correcting device of thermistor and the temperature characterisitic modification method of thermistor, the characteristic revision of the data value that can be exported according to detected temperature by thermistor is efficiently linear.
In the temperature characterisitic correcting device of the thermistor of the disclosure first embodiment, voltage conversion circuit is configured to, multiple voltage dividing resistance circuit optionally can be connected with thermistor, above-mentioned each divider resistance value is set to, for the different temperature range that thermistor detects, the change in voltage corresponding to the change of the resistance value of thermistor is made to have similar linear characteristic respectively.That is, the change of the resistance value of original thermistor presents the characteristic of exponential function, but when the change of this resistance value is detected as the change in voltage via voltage dividing resistance circuit, obtains the region in substantial linear.
In memory circuit, have following coefficient for the area stores presenting the similar linear characteristic of being paid by each voltage dividing resistance circuit, this coefficient is the coefficient obtained to be A/D transformed value actual certain in divider resistance value carry out repeatedly approximation to function in advance relative to the characteristic that temperature variation presents.The change of the A/D transform data value of the voltage signal that computing circuit exports according to voltage conversion circuit, the connection of voltage dividing resistance circuit each in thermistor and voltage conversion circuit is switched, and, read the coefficient corresponding to the voltage dividing resistance circuit be connected with thermistor from memory circuit, carry out repeatedly approximation to function computing.Thus, based on the resistance value in each voltage dividing resistance circuit, the temperature closer to actual characteristic can be obtained continuously.And for the threshold value of the exporting change amount derived by required output characteristics and the region defined, the data after output transform, with for each temperature linearly characteristic.
According to formation described above, detected by thermistor and the temperature data exported by temperature characterisitic correcting device, in the scope meeting required output characteristics, become linear.And the quantity of necessary voltage dividing resistance circuit is Min. for this reason, therefore, it is possible to form temperature characterisitic correcting device by number of components less than ever.
Accompanying drawing explanation
By the detailed description done below in conjunction with accompanying drawing, above-mentioned purpose of the present disclosure and other object, feature and advantage become clearer and more definite.
Fig. 1 is the process flow diagram of the action representing temperature characterisitic correcting device in the 1st embodiment,
Fig. 2 is the process flow diagram of the contents processing of step S4 when representing startup,
Fig. 3 is the process flow diagram of the contents processing of step S4 when representing usual action,
Fig. 4 (a) is that the figure of the codomain representing temperature range and the A/D transformed value distribute each metering circuit, Fig. 4 (b) represent that each codomain is finally arranged to the figure of the state of linear characteristic,
Fig. 5 is the figure representing that the numerical value of each metering circuit corresponding with Fig. 4 (a) is had a guide look of,
Fig. 6 (a) is the figure of the characteristic of actual A/D transformed value, Fig. 6 (b) represents figure Fig. 6 (a) being carried out to the curve after 3 approximations to function, Fig. 6 (c) is the figure representing the data value characteristic exported according to temperature by temperature characterisitic correcting device
Fig. 7 is the figure of an example of the accuracy of detection representing the A/D transform data finally obtained,
The figure of Fig. 8 (a) to be the figure of the structure representing temperature characterisitic correcting device, Fig. 8 (b) be example of the resistance value represented in each metering circuit,
Fig. 9 is the figure of the variation representing metering circuit,
Figure 10 is representation class like the figure of the relation of the range of linearity and accuracy of detection,
Figure 11 is the figure of the resistance variation characteristic representing the thermistor corresponding to temperature variation,
Figure 12 (a) represents the figure resistance variations of thermistor having been carried out to characteristic when A/D converts, and Figure 12 (b) is the figure of the characteristic representing the final A/D transformed value exported,
Figure 13 is the process flow diagram of the action representing temperature characterisitic correcting device in the 2nd embodiment,
Figure 14 is the figure be described the calculation process based on wave filter,
Figure 15 is the figure of the structure representing temperature characterisitic correcting device in the 3rd embodiment,
Figure 16 is the figure of an example of the resistance value represented in each metering circuit and each diagnostic circuit,
Figure 17 be when representing startup and usual action time the process flow diagram of process,
Figure 18 is the figure of the structure representing temperature characterisitic correcting device in the 4th embodiment,
Figure 19 is the figure of an example of the resistance value represented in each diagnostic circuit,
The figure of Figure 20 (a) to be the figure of an example of the accuracy of detection representing the A/D transform data finally obtained, Figure 20 (b) be example of the accuracy of detection representing the A/D transform data obtained for each diagnostic circuit,
Figure 21 be when representing startup and usual action time the process flow diagram of process,
Figure 22 is the figure of the structure representing temperature characterisitic correcting device in the 5th embodiment,
Figure 23 is the figure of an example of the resistance value represented in diagnostic circuit,
Figure 24 is the figure of an example of the accuracy of detection representing the A/D transform data obtained for diagnostic circuit.
Embodiment
(the 1st embodiment)
First, in the present embodiment, the principle in order to the corresponding A/D transform data of the temperature obtained with detect is described.As shown in figure 11, the resistance value of general thermistor is relative to the characteristic of the change exponentially function of temperature.Be specially, first, setting the constant of initial deviation as B, if the reference value of resistance value is R0, if when the reference value of temperature is T0, utilize formula (1) to try to achieve the resistance value R of thermistor and the relation of temperature T.
R＝R0×exp(B×(1/T-1/T0)) (1)
Thermistor is connected with voltage dividing resistance circuit etc., and A/D conversion is carried out to change in voltage, and the situation detecting the resistance change of this thermistor is more.Now, the A/D transformed value corresponding with temperature to become shown in Figure 12 (a) like that, and at low-temperature region and high-temperature area with nonlinearities change, but middle temperature area between which presents substantial linear change.Below, this region is claimed to be similar linear characteristic region.
When by thermistor detected temperatures, if use the similar linear characteristic region of A/D transformed value, then all right.In addition, even same thermistor, the temperature range and the slope that become similar linear characteristic region also can change according to the divider resistance value of connected voltage dividing resistance circuit, therefore, in patent documentation 1, the resistance value of variable resistance circuit is changed according to temperature range.
The A/D conversion characteristics of the temperature shown in Figure 12 (a) can use repeatedly function to be similar to, therefore, if carry out repeatedly approximation to function computing according to the divider resistance value of each voltage dividing resistance circuit and revise, then can obtain the more accurately temperature corresponding to the A/D transformed value of reality.At this, when carrying out correction computing, which kind of degree its accuracy requirement reaches is determined according to the specification of be suitable for application.Therefore, by switching the connection of multiple voltage dividing resistance circuit and their links being used, thus the similar linear characteristic region being met the scope of specification by revising computing is made to meet specification.Be specially, by the linear characteristic approximate transform in middle temperature area for requiring output characteristics.Finally, as shown in Figure 12 (b), the A/D transform data corresponding to detected temperatures becomes the linear of monotone increasing and exports.Below do more specific description.
As shown in Fig. 8 (a), the temperature characterisitic correcting device of present embodiment comprises: the metering circuit portion 2 be connected with thermistor 1, test section 3, CPU4, efferent 5 and flash memories 6.Metering circuit portion 2 is voltage conversion circuit, and CPU4 is computing circuit, and flash memories 6 is memory circuit.Metering circuit portion 2 has multiple such as 3 metering circuits 21,22,23.Metering circuit 21,22,23 is voltage dividing resistance circuit.3 resistive element R1 ~ R3 connect with 3 interrupteur SW (1 ~ 3,4 ~ 6,7 ~ 9) and form respectively by metering circuit 21,22,23 between power supply with ground connection.
Such as, about metering circuit 21, at the points of common connection place of resistive element R1 and R2, the points of common connection place of resistive element R2 and R3 and be inserted with interrupteur SW 1, SW2, SW3 respectively between resistive element R3 and ground connection.In metering circuit 22, replace interrupteur SW 1, SW2, SW3, be inserted with interrupteur SW 4, SW5, SW6, in metering circuit 23, be inserted with interrupteur SW 7, SW8, SW9 similarly.The break-make utilizing CPU4 to control these interrupteur SW 1 ~ SW9 switches, and any one metering circuit in metering circuit 21 ~ 23 is connected with thermistor 1.And as shown in Fig. 8 (b), in the middle of metering circuit 21 ~ 23 is respective, at SET1, SET2, SET3, the resistance value of resistive element R1 ~ R3 is different.
The voltage signal exported via metering circuit portion 2 is input to test section 3.Further, to the both end voltage of test section 3 input resistance element R2.Test section 3 has amplifying circuit and A/D transducer, after amplifying the voltage signal be transfused to, carries out A/D conversion and inputs to CPU4.The control program that CPU4 will perform and the coefficient data etc. revising computing is stored in flash memories 6.CPU4 reads in the data that are transfused to and carries out correction computing etc., then exports operation result to efferent 5.CPU4 by the linear characteristic approximate transform in middle temperature area for requiring output characteristics.Efferent 5 is such as SENT (monolateral nibble transmission: the data be transfused to are outputted to outside with the data layout corresponding to communication standard by the interface that SingleEdge Nibble Transmission) communication standard such as sender etc. and SENT is corresponding.
And, metering circuit in metering circuit portion 2 is not to use 3 resistive elements, such as can use 2 resistive elements R1, R2 as Suo Shi Fig. 9 (a), also can be made up of the series circuit of current source and resistive element R1 as Suo Shi Fig. 9 (b).In addition, being set to supply voltage is such as 3.3V, and the bit number being set to A/D conversion is 12.
Below the effect of present embodiment is described.As shown in Figure 1, when the resistance value of thermistor 1 changes according to temperature (S1), its change is the change (S2) of voltage in metering circuit portion 2.This voltage is exaggerated (S3) and by after A/D conversion (S4), carries out correction computing (S5) by CPU4 in test section 3.Then, carry out the adjustment (S6) of output data value according to the sensitivity be required, and utilize the data layout of such as SENT communication to export the value after adjustment to outside (S7) by efferent 5.And, in above-mentioned steps S4, A/D conversion is carried out to the voltage after amplifying in step s3, and carries out the selection of metering circuit 21 ~ 23 according to this A/D transform data value.
As shown in Fig. 4 (a), roughly cover measuring tempeature scope-30 DEG C ~ 180 DEG C by switching use 3 metering circuits 21 ~ 23.And, for each metering circuit 21 ~ 23, respective detected temperatures scope and expect according to its temperature range export A/D transformed value be configured to as shown in Figure 5.At this, the respective expectation A/D transformed value of each metering circuit 21 ~ 23 is selected as the codomain obtaining similar linear characteristic region.
Such as, via in metering circuit and the A/D transformed value obtained presents the characteristic as Figure 10 (a) time, the detection resolution corresponding to each detected temperatures shown in Figure 10 (b), declines at low-temperature region and high-temperature area, rises at middle temperature area.Can regard the temperature range in similar linear characteristic region as, which kind of degree is this detection resolution reach and different as requested.Therefore, be such as 8LSB/ DEG C by making to require detection resolution clearly, for 1 metering circuit, the temperature range can guaranteeing to regard as similar linear characteristic region is to greatest extent.Region Aa is the range of linearity in sensing range in the past.But, there is no clear and definite definition, to set the definition regarding the range of linearity as at every turn.Region Ab is the range of linearity in sensing range of the present disclosure.In addition, by being set as threshold value from output sensitivity characteristic and obtaining region Ab.
Thus, the switching carrying out metering circuit 21 ~ 23 as described below controls in step s 4 which.As shown in Figure 2, when the startup of temperature characterisitic correcting device, CPU4 reads in and switches to metering circuit 21 ~ 23 and the A/D transformed value obtained.Then, whether be within the scope of expected value corresponding separately according to the A/D transformed value obtained via each metering circuit 21 ~ 23, one in initial selected metering circuit 21 ~ 23.
And, as shown in Fig. 4 (a) He Fig. 5, in the expectation A/D transformed value relevant with each metering circuit 21 ~ 23, between each metering circuit 21 and 22, between metering circuit 22 and 23, there is equitant codomain.This is the switching carrying out metering circuit 21 ~ 23 in order to have hysteresis characteristic swimmingly.
If only the A/D transformed value of metering circuit 21 is expected value (S14: yes), then initial selected metering circuit 21 (S17), if only the A/D transformed value of metering circuit 23 is expected value (S18: yes), then initial selected metering circuit 23 (S19).And if metering circuit 21 and 22, or the A/D transformed value of metering circuit 22 and 23 is expected value (S16: yes), then initial selected metering circuit 22 (S17).This is because metering circuit 22 is set at middle temperature area, and therefore this metering circuit 22 of prioritizing selection is expected to reduce the frequency later carrying out switching.
In step S4 after initial selected, carry out the process shown in Fig. 3.According to the result of initial selected, carry out A/D conversion respectively by metering circuit 21,22,23.As shown in Fig. 4 (a), the lower limit of the A/D transformed value used in metering circuit 21,22 is set to α 1, α 2 respectively, and the upper limit of the A/D transformed value used in metering circuit 22,23 is set to β 2, β 3 respectively.When having been carried out A/D conversion by metering circuit 21 (S21), if its A/D transformed value is α less than 1 (S22: yes), then return step S21, continued to use metering circuit 21.If described A/D transformed value, more than α 1 (S22: no), moves to step S23.
When having been carried out A/D conversion by metering circuit 22 (S23), if its A/D transformed value is β more than 2 (S24: yes) and is α less than 2 (S25: yes), then return step S23, continued to use metering circuit 22.If be judged as "No" in step s 24 which, then return step S21, if be judged as "No" in step s 25, then move to step S26.
When having been carried out A/D conversion by metering circuit 23 (S26), if its A/D transformed value is β more than 3 (S27: yes), then return step S26, continued to use metering circuit 23.If be judged as "No" in step s 27, then move to step S23.
Refer again to Fig. 1.As mentioned above, in step s 5, when selecting metering circuit 21 ~ 23 in step s 4 which, CPU4 uses 3 functions to revise for A/D transformed value.About the actual A/D transformed value X obtained
1, obtain coefficient A, B, C, D of 3 functions be assumed to be as the corresponding A/D conversion characteristics of the resistance value respective to metering circuit 21 ~ 23 in advance, and be stored in advance in flash memories 6.Then formula (2) is utilized to obtain temperature Y
1.
Y
1＝AX
1 3+BX
1 2+CX
1+D (2)
The temperature Y obtained as mentioned above
1become with Fig. 6 (b) Suo Shi such to the A/D conversion characteristics of reality carry out 3 times approximate after curve be worth accordingly.
Finally, in order to as shown in Fig. 4 (b) and Fig. 6 (c), export with communicate at SENT in transmit temperature data time the output characteristics (≒ 8LSB/ DEG C that must meet) digital value accordingly, by temperature Y
1as temperature X
2be updated to the formula (3) of output function, and export the digital value Y of monotone increasing
2.Wherein, E, F are coefficient.
Y
2＝EX
2+F...(3)
Carry out as mentioned above processing as a result, as shown in Figure 7, for temperature detection range-30 ° ~ 180 DEG C based on thermistor 1, the output characteristics be required and accuracy of detection 8LSB/ DEG C are guaranteed.In addition, the source (" SAEJ2716_Revised JAN2010Page42 of 56 ") of Fig. 6 (c) is marked.
As mentioned above, according to the present embodiment, metering circuit portion 2 is configured to, metering circuit 21 ~ 23 optionally can be connected with thermistor 1, these each metering circuits 21 ~ 23 are set as, for the different temperature range that thermistor 1 detects, the change in voltage corresponding to the resistance change of thermistor 1 is made to have similar linear characteristic respectively.
The change of the A/D transform data value of the voltage signal that CPU4 exports according to metering circuit portion 2, switch the connection of thermistor 1 and each metering circuit 21 ~ 23, and, the coefficient corresponding to the metering circuit be connected with thermistor 1 is read from flash memories 6, carry out 3 approximation to function computings, obtain the temperature corresponding to A/D transformed value.And for the region defined according to the threshold value of the exporting change amount derived by the output characteristics be required, the data after output transform, to become linear characteristic for each temperature.
Thus, detected by thermistor 1 and the temperature data exported by temperature characterisitic correcting device, in the scope meeting the output characteristics be required, become linear.And the quantity of necessary metering circuit is minimum limit for this reason, therefore temperature characterisitic correcting device can be formed by number of components less than ever.In addition, due to make in the temperature ramp de that detects at thermistor 1 to each metering circuit 21 ~ 23 carry out connecting switch threshold data used with carry out in the temperature decline process detected at thermistor 1 above-mentioned be connected to switch between threshold data used have difference, therefore CPU4 stably can carry out switchings control.
(the 2nd embodiment)
Below, for the symbol that the portion markings identical with the 1st embodiment is identical, and omit the description, different parts is described.As shown in figure 13, in the 2nd embodiment, CPU4 is provided with the step S11 performing filtering process computing between step S5, S6.When carrying out connection and switch between metering circuit 21 ~ 23, in order to make the change of the A/D transformed value corresponding with temperature after carrying out 3 approximations to function level and smooth, carry out this filtering process as such as weighted mean process.
Such as, as shown in figure 14, the data obtained up-to-date data, its previous and the first two are multiplied by weighting coefficient α, β, γ respectively and to the output valve of the value after their summations as this.In the present embodiment, the summation of weighting coefficient α, β, γ is 1.Thus, even if the A/D transformed value such as when being switched to metering circuit 22 from metering circuit 21 exists a small amount of deviation, also data value can be revised, to make the variation corresponding to this deviation less.
(the 3rd embodiment)
In the temperature characterisitic correcting device of the 1st embodiment, voltage conversion circuit 2 has metering circuit 21 ~ 23, and any one of therefore such as interrupteur SW 1 ~ SW9 may be fixed on OFF state or ON state is constant or the resistance value of resistive element R1 ~ R3 rheological parameters' change with time may occur and measured temperature change.Thus, in the 3rd embodiment, there is the exception for detecting as described above and carry out the structure of fault verification.
As shown in figure 15, in the temperature characterisitic correcting device of the 3rd embodiment, the voltage conversion circuit 2 of the 1st embodiment is replaced into voltage conversion circuit 11.Voltage conversion circuit 11 comprises metering circuit portion 11M and diagnostic circuit portion 11D, and 11M its structure in metering circuit portion is identical with the voltage conversion circuit 2 of the 1st embodiment, for detected temperatures.In addition, as shown in figure 16, the metering circuit 21,22,23 of diagnostic circuit portion 11D and metering circuit portion 11M accordingly, there is at SET4, SET5, SET6 diagnostic circuit 121,122,123 respectively that be made up of same resistance value.Diagnostic circuit 121 ~ 123 is diagnosis voltage dividing resistance circuit.
In diagnostic circuit 121 ~ 123, the switch corresponding with the interrupteur SW 1 ~ SW9 of metering circuit 21 ~ 23 is interrupteur SW 11 ~ SW19.And the CPU13 replacing CPU4 uses diagnostic circuit 121 ~ 123 to carry out fault diagnosis or the abnormality detection of voltage conversion circuit 11.In the present embodiment, CPU13 is computing circuit.
Below, the effect of the 3rd embodiment is described.As shown in figure 17, the step S11 ~ S19 of the 1st embodiment performs (S31) as process during startup by CPU13, selects the metering circuit 2 used in temperature survey.Then, carry out the usual process performing step S21 ~ S27 in a same manner as in the first embodiment, obtain the 1st measured temperature T1 (S32).Then, use the diagnostic circuit 121,122,123 corresponding with metering circuit 2 used in the measurements similarly to perform and usually process, obtain the 2nd measured temperature T2 (S33).
Then, obtain the absolute value of the difference of the 1st measured value T1 and the 2nd measured value T2, judge that whether the absolute value of this difference is more than the threshold value Tt (S34) of fault verification.If described absolute value is less than threshold value Tt (S34: no), then returns step S32, proceed usual action.On the other hand, if described absolute value is more than threshold value Tt (S34: yes), be then judged to be that metering circuit 2 breaks down.In addition, preset threshold value Tt and be kept in flash memories 6.
As mentioned above, according to the 3rd embodiment, there is the diagnostic circuit 121 ~ 123 corresponding with the detected temperatures scope of the thermistor 1 covered by metering circuit 21 ~ 23, whether CPU13 obtains the difference of temperature data and the temperature data obtained by diagnostic circuit 121 ~ 123 obtained by metering circuit 21 ~ 23, and be that more than threshold value Tt carries out fault diagnosis according to the absolute value of described difference.Detect therefore, it is possible to be fixed on ON to the interrupteur SW that in metering circuit 2 or diagnostic circuit 12, at least one party occurs or be fixed on the fault that OFF etc. causes, the reliability of temperature characterisitic correcting device can be improved.
Further, the resistance value of diagnostic circuit 121 ~ 123 is set as the value identical with corresponding metering circuit 21 ~ 23.Thus, diagnostic circuit 121 ~ 123 has the linear characteristic identical with metering circuit 21 ~ 23, therefore, it is possible to carry out fault diagnosis with more high precision.
(the 4th embodiment)
As shown in figure 18, the temperature characterisitic correcting device of the 4th embodiment has voltage conversion circuit 14, and the diagnostic circuit portion 11D of voltage conversion circuit 11 is replaced with diagnostic circuit portion 14D by voltage conversion circuit 14.Diagnostic circuit portion 14D and metering circuit 21 ~ 23 correspondingly have diagnostic circuit 154,155.In the present embodiment, diagnostic circuit 154,155 is diagnosis voltage dividing resistance circuit.The value that each resistance value of the resistive element R1 ~ R3 in diagnostic circuit 154,155 is SET4, SET5 shown in Figure 19.
Figure 20 (a) in the same manner as Fig. 7, be the figure of an example of the accuracy of detection representing the A/D transform data finally obtained, Figure 20 (b) is for diagnostic circuit 154,155, carries out the result after 3 approximation to function computings identical with metering circuit 2.That is, utilize diagnostic circuit 154,155, cover the scope of temperature detection range-30 ° ~ 180 DEG C of thermistor 1 in the same manner as metering circuit 21 ~ 23, the maximal value of error is roughly 10LSB.To this, the tightness of linear characteristic is set slightly relax than metering circuit 21 ~ 23.Further, for diagnostic circuit 154,155, will be used for carrying out the coefficient storage of above-mentioned 3 approximation to function computings in flash memories 6 in advance.
Below, the effect of the 4th embodiment is described.As shown in figure 21, the CPU16 replacing CPU13, after step S31, processes (S36) when carrying out the startup using diagnostic circuit 154,155.That is, the temperature range of judgement measuring object is suitable for any one of diagnostic circuit 154,155.Then, after execution step S32, any one utilizing diagnostic circuit 154,155 obtains the 2nd measured temperature T2 (S37).Then, perform step S34, S35 in a same manner as in the third embodiment.In the present embodiment, CPU16 is computing circuit.
As mentioned above, according to the 4th embodiment, with metering circuit 21 ~ 23 correspondingly, there is the less diagnostic circuit of quantity 154,155, and cover measuring tempeature scope.In addition, in flash memories 6, coefficient for carrying out 3 approximation to function computings is prestored for diagnostic circuit 154,155, CPU16 reads above-mentioned coefficient, obtain and by 3 approximation to function computings, revised temperature has been carried out to the data value after A/D conversion by diagnostic circuit 154,155, calculate and similar linear characteristic is transformed to the data after linear characteristic.
And, in a same manner as in the third embodiment, obtain the temperature data and the difference of the temperature data obtained by diagnostic circuit 154,155 that are obtained by diagnostic circuit 121 ~ 123, carry out fault diagnosis.Thus, although fault diagnosis precision is not as good as the 3rd embodiment, the probability broken down in diagnostic circuit 154,155 side reduces, therefore, it is possible to improve reliability further.
(the 5th embodiment)
As shown in figure 22, the temperature characterisitic correcting device of the 5th embodiment has voltage conversion circuit 17, and the diagnostic circuit portion 14D of the 4th embodiment is replaced with diagnostic circuit portion 17D by voltage conversion circuit 17.Diagnostic circuit portion 17D corresponds to metering circuit 21 ~ 23 and only has 1 diagnostic circuit 156.The each resistance value of resistive element R1 ~ R3 in diagnostic circuit 156 as shown in figure 23, in SET6, is the value that the metering circuit 22 corresponding with the zone line of measuring tempeature scope is identical.In the present embodiment, diagnostic circuit 156 is diagnosis voltage dividing resistance circuit.
And, in the 5th embodiment, the approximation to function computing of 3 approximation to function computings that metering circuit 2 carries out more high reps that diagnostic circuit 156 is compared.Figure 24 represents the result after carrying out 6 approximation to function computings and 8 approximation to function computings, and the scale of the longitudinal axis is 2 times of Figure 20.Namely, utilize diagnostic circuit 156, cover the scope of temperature detection range-30 ° ~ 180 DEG C of thermistor 1 in the same manner as metering circuit 21 ~ 23, the max value of error in 6 approximation to function computings is more than 30LSB, and the max value of error of 8 approximation to function computings is below 20LSB.
In flash memories 6, for diagnostic circuit 156, also prestore the coefficient for carrying out higher order functionality operate approximately, the CPU18 replacing CPU16 reads above-mentioned coefficient, obtain and by higher order functionality operate approximately, revised temperature has been carried out to the data value after A/D conversion by diagnostic circuit 156, calculate the data similar linear characteristic being transformed to linear characteristic.
And in the 3rd embodiment, step S33, CPU18 shown in Figure 17 utilize diagnostic circuit 156 to obtain the 2nd measured temperature T2, perform step S34, S35 later in a same manner as in the third embodiment.
As mentioned above, according to the 5th embodiment, in the repeatedly approximation to function computing that diagnostic circuit 156 is used, the function of 3 the approximation to function computing high orders using matching measurement circuit 2 to use, therefore relaxed the tightness of linear characteristic, the quantity of diagnostic circuit can have been cut down further.And, 1 diagnostic circuit 156 is only set, and its resistance value is set as the value identical with metering circuit 22, therefore, it is possible to carry out fault diagnosis under the state maintaining high reliability.
The present invention is not limited only to the embodiment recorded in above-mentioned or accompanying drawing, can carry out distortion as follows and expansion.
The quantity of metering circuit is not limited to 3, suitably can select according to the temperature range etc. as measuring object.
Revise and be also not limited to 3 approximations to function, also can use the function of more than 2 times or 4 times.
The bit number etc. of supply voltage and A/D conversion suitably can be changed according to respective design.In addition, accuracy of detection is also not limited to 8LSB/ DEG C.
In the 3rd, the 5th embodiment, the resistance value of diagnostic circuit 121 ~ 123,156 can be set as the value different from metering circuit 2.
6 times, 8 times are not limited to the higher order functionality operate approximately that diagnostic circuit 121 ~ 123,156 carries out, as long as the number of times higher than the number of times of metering circuit side.
Efferent 5 also can tackle the communication standard beyond SENT.In addition, can efferent 5 be set as required.
Memory circuit is not limited to be flash memories 6, also can be SRAM or DRAM etc.
The disclosure describes according to embodiment, but is interpreted as the disclosure and is not limited to this embodiment and structure.The disclosure also comprises the distortion in various variation and equivalent scope.And various combination and embodiment and comprise only key element in above-mentioned key element, comprise more key elements or comprise other combination and the embodiment of less key element, all bring in the scope of category of the present disclosure and technological thought.
Claims (10)
1. a temperature characterisitic correcting device for thermistor, comprising:
Voltage conversion circuit (2), there are the different multiple voltage dividing resistance circuit of divider resistance value (21,22,23), thermistor (1) can optionally be connected with each voltage dividing resistance circuit, described each divider resistance value is set to, for the different temperature range that described thermistor detects, the change in voltage corresponding to the resistance change of described thermistor is made to have similar linear characteristic respectively;
A/D transducer (3), carries out A/D conversion to the voltage signal that this voltage conversion circuit exports;
Computing circuit (4,13,16,18), is transfused to the data after described A/D conversion, row operation of going forward side by side; With
Memory circuit (6), stores and has carried out the repeatedly coefficient of approximation to function in advance, so that the similar linear characteristic of being paid by described each voltage dividing resistance circuit is transformed to linear characteristic,
Described computing circuit, according to the change of the data value after described A/D conversion, switches the connection of each voltage dividing resistance circuit in described thermistor and described voltage conversion circuit,
And, described computing circuit reads the coefficient corresponding to voltage dividing resistance circuit be connected with described thermistor from described memory circuit, obtain and utilize repeatedly approximation to function computing to carry out revised temperature to the data value after described A/D conversion, export for the region defined according to the threshold value of the exporting change amount derived by the output characteristics be required and described similar linear characteristic is transformed to the data after linear characteristic.
2. the temperature characterisitic correcting device of thermistor as claimed in claim 1,
The computing of described repeatedly approximation to function is 3 approximation to function computings.
3. the temperature characterisitic correcting device of thermistor as claimed in claim 1 or 2,
Carry out in the process that the connection carrying out described thermistor and described each voltage dividing resistance circuit in the process that described computing circuit makes the temperature that detects at described thermistor rise switches threshold data used, reduce with the temperature detected at described thermistor described connection switching threshold data used and having difference.
4. the temperature characterisitic correcting device of thermistor as claimed in claim 1 or 2,
The data that described computing circuit exports for the front and back switched in the connection carrying out described thermistor and described each voltage dividing resistance circuit, carry out based on average weighted filtering operation process.
5. the temperature characterisitic correcting device of thermistor as claimed in claim 1 or 2,
Having diagnosis voltage dividing resistance circuit (121,122,123,154,155,156), is the voltage dividing resistance circuit of the fault diagnosis corresponding with the detected temperatures scope of the described thermistor covered by described multiple voltage dividing resistance circuit,
Described A/D transducer also carries out A/D conversion to the voltage signal that described diagnosis voltage dividing resistance circuit exports,
In described memory circuit, also store for described diagnosis voltage dividing resistance circuit and carried out the repeatedly coefficient of approximation to function in advance, so that the similar linear characteristic of being paid by this diagnosis voltage dividing resistance circuit is transformed to linear characteristic,
Described computing circuit (13,16,18) also reads the coefficient of the diagnosis voltage dividing resistance circuit corresponding to voltage dividing resistance circuit be connected with described thermistor from described memory circuit, obtain and utilize repeatedly approximation to function computing to carry out revised temperature to the data value after A/D conversion by described diagnosis voltage dividing resistance circuit, calculate and described similar linear characteristic is transformed to the data after described linear characteristic
Whether the difference of data and the data obtained by described diagnosis voltage dividing resistance circuit obtained by described voltage dividing resistance circuit obtained by described computing circuit (13,16,18), be more than the threshold value of regulation, carry out fault diagnosis according to described difference.
6. the temperature characterisitic correcting device of thermistor as claimed in claim 5,
Described diagnosis voltage dividing resistance circuit (121,122,123) is provided with multiple with described multiple voltage dividing resistance circuit accordingly, and is set to the resistance value identical with voltage dividing resistance circuit corresponding separately.
7. the temperature characterisitic correcting device of thermistor as claimed in claim 5,
To the repeatedly approximation to function computing that described diagnosis voltage dividing resistance circuit uses, use the function of the repeatedly approximation to function computing high order that voltage dividing resistance circuit uses described in comparison.
8. the temperature characterisitic correcting device of thermistor as claimed in claim 7,
1 (156) described diagnosis voltage dividing resistance circuit is only set, and its resistance value is set as the value identical with the voltage dividing resistance circuit of 1 in described voltage dividing resistance circuit.
9. a temperature characterisitic modification method for thermistor,
Use multiple voltage dividing resistance circuit that divider resistance value is different, described each divider resistance value is set to, and for the different temperature range that thermistor detects, makes the change in voltage corresponding to the resistance change of described thermistor have similar linear characteristic respectively,
A/D conversion is carried out with the voltage signal exported under the some states be connected in described voltage dividing resistance circuit at described thermistor,
According to the change of the data value after described A/D conversion, switch the connection of each voltage dividing resistance circuit in described thermistor and described voltage conversion circuit,
In order to the similar linear characteristic of being paid by the voltage dividing resistance circuit be connected with described thermistor is transformed to linear characteristic, and use the coefficient having carried out repeatedly approximation to function in advance to carry out repeatedly approximation to function computing, export for the region defined according to the threshold value of the exporting change amount derived by the output characteristics be required and described similar linear characteristic is transformed to the data after linear characteristic.
10. the temperature characterisitic modification method of thermistor as claimed in claim 9,
The computing of described repeatedly approximation to function is 3 approximation to function computings.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
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| JP2014077742 | 2014-04-04 | ||
| JP2014-077742 | 2014-04-04 | ||
| JP2014260385A JP2015200633A (en) | 2014-04-04 | 2014-12-24 | Device for correcting temperature characteristic of thermistor and method for correcting temperature characteristic of thermistor |
| JP2014-260385 | 2014-12-24 |
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| CN104977096A true CN104977096A (en) | 2015-10-14 |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105955338A (en) * | 2016-07-19 | 2016-09-21 | 浙江绍兴苏泊尔生活电器有限公司 | Plateau self-adaptive method for food processor |
| CN107655588A (en) * | 2016-07-25 | 2018-02-02 | 宝沃汽车（中国）有限公司 | A kind of temperature multrirange device for accurately measuring and method |
| CN108362400A (en) * | 2018-01-17 | 2018-08-03 | 广东美的厨房电器制造有限公司 | It is capable of the temperature measuring equipment of self checking and the method for temperature measuring equipment self checking |
| CN108571395A (en) * | 2017-06-23 | 2018-09-25 | 株式会社电装 | Engine temperature measurement device and engine temperature assay method |
| CN108710392A (en) * | 2018-04-26 | 2018-10-26 | 广东美的厨房电器制造有限公司 | Oven preheating control method, device and computer readable storage medium |
| CN109601009A (en) * | 2017-08-01 | 2019-04-09 | 泰合意株式会社 | The bearing calibration of temperature sensor |
| CN111623898A (en) * | 2020-06-24 | 2020-09-04 | 广东纽恩泰新能源科技发展有限公司 | NTC thermistor temperature and resistance detection method and temperature sensor detection method |
| CN112187263A (en) * | 2020-08-28 | 2021-01-05 | 国电南瑞南京控制系统有限公司 | AD sampling value compensation coefficient iteration method and system for resistance voltage division sampling technology |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2544591A1 (en) * | 1975-08-06 | 1977-04-14 | Degussa | Linearising circuit for measuring probes - uses summing amplifier with decade selector switch for matching non:linear characteristics |
| US4106341A (en) * | 1977-01-03 | 1978-08-15 | General Electric Company | Linearized thermistor temperature measuring circuit |
| JPH06168387A (en) * | 1992-11-30 | 1994-06-14 | Matsushita Electric Works Ltd | Thermal sensor |
| CN203396511U (en) * | 2013-06-04 | 2014-01-15 | 广东芬尼克兹节能设备有限公司 | High-precision temperature detecting device based on thermistor |
-
2015
- 2015-04-03 CN CN201510158036.7A patent/CN104977096A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2544591A1 (en) * | 1975-08-06 | 1977-04-14 | Degussa | Linearising circuit for measuring probes - uses summing amplifier with decade selector switch for matching non:linear characteristics |
| US4106341A (en) * | 1977-01-03 | 1978-08-15 | General Electric Company | Linearized thermistor temperature measuring circuit |
| JPH06168387A (en) * | 1992-11-30 | 1994-06-14 | Matsushita Electric Works Ltd | Thermal sensor |
| CN203396511U (en) * | 2013-06-04 | 2014-01-15 | 广东芬尼克兹节能设备有限公司 | High-precision temperature detecting device based on thermistor |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105955338A (en) * | 2016-07-19 | 2016-09-21 | 浙江绍兴苏泊尔生活电器有限公司 | Plateau self-adaptive method for food processor |
| CN107655588A (en) * | 2016-07-25 | 2018-02-02 | 宝沃汽车（中国）有限公司 | A kind of temperature multrirange device for accurately measuring and method |
| CN108571395A (en) * | 2017-06-23 | 2018-09-25 | 株式会社电装 | Engine temperature measurement device and engine temperature assay method |
| CN109601009A (en) * | 2017-08-01 | 2019-04-09 | 泰合意株式会社 | The bearing calibration of temperature sensor |
| CN108362400A (en) * | 2018-01-17 | 2018-08-03 | 广东美的厨房电器制造有限公司 | It is capable of the temperature measuring equipment of self checking and the method for temperature measuring equipment self checking |
| CN108710392A (en) * | 2018-04-26 | 2018-10-26 | 广东美的厨房电器制造有限公司 | Oven preheating control method, device and computer readable storage medium |
| CN111623898A (en) * | 2020-06-24 | 2020-09-04 | 广东纽恩泰新能源科技发展有限公司 | NTC thermistor temperature and resistance detection method and temperature sensor detection method |
| CN112187263A (en) * | 2020-08-28 | 2021-01-05 | 国电南瑞南京控制系统有限公司 | AD sampling value compensation coefficient iteration method and system for resistance voltage division sampling technology |
| CN112187263B (en) * | 2020-08-28 | 2022-07-01 | 国电南瑞南京控制系统有限公司 | AD sampling value compensation coefficient iteration method and system for resistance voltage division sampling technology |
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