(19)
(11)EP 2 477 017 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
11.12.2019 Bulletin 2019/50

(21)Application number: 12151308.9

(22)Date of filing:  16.01.2012
(51)International Patent Classification (IPC): 
G01K 7/24(2006.01)
G01R 31/28(2006.01)
G01K 15/00(2006.01)

(54)

Diagnostic system and method for a thermistor amplifier circuit

Diagnosesystem und -verfahren für einen Thermistorverstärkerstromkreis

Système de diagnostic et procédé pour un circuit amplificateur de thermistor


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 18.01.2011 US 201113008571

(43)Date of publication of application:
18.07.2012 Bulletin 2012/29

(73)Proprietor: ABB Schweiz AG
5400 Baden (CH)

(72)Inventors:
  • Vicente, Nataniel Barbosa
    Louisville, KY 40225 (US)
  • Greenwood, Todd Elliott
    Louisville, KY 40225 (US)
  • Williams, Craig Benjamin
    Louisville, KY 40225 (US)

(74)Representative: Aipex B.V. 
P.O. Box 30223
3001 DE Rotterdam
3001 DE Rotterdam (NL)


(56)References cited: : 
JP-A- S59 200 934
US-A1- 2009 110 022
US-A- 5 183 039
US-B1- 6 288 638
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION



    [0001] The subject matter disclosed herein relates to a diagnostic system for a thermistor amplifier circuit.

    [0002] In the field of healthcare US2009/110022 A1 describes a temperature detection circuit coupled selectively to a thermistor and one of two sources representing the impedance at respective ends of a temperature range. A processor is used to calibrate the thermistor.

    BRIEF DESCRIPTION OF THE INVENTION



    [0003] A diagnostic system for a thermistor amplifier circuit as defined in claim 1 is provided.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0004] The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

    FIG. 1 is a schematic of a motor control system having a diagnostic system for a thermistor amplifier circuit in accordance with an exemplary embodiment;

    FIG. 2 is a graph of an exemplary control signal utilized in the diagnostic system of FIG. 1 and two exemplary output signals generated by a thermistor amplifier circuit in the motor control system of FIG. 1;

    FIG. 3 is a schematic of a lookup table utilized in the diagnostic system of FIG. 1; and

    FIGS. 4-6 are flowchart diagrams for a diagnostic method for the thermistor amplifier circuit of FIG. 1 in accordance with an example not covered by the claims.



    [0005] The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

    DETAILED DESCRIPTION OF THE INVENTION



    [0006] Referring to FIG. 1, a motor control system 10 for controlling operation of a motor 44 is illustrated. The motor control system 10 has a diagnostic system 40 for a thermistor amplifier circuit 30 in accordance with an exemplary embodiment. The motor control system 10 includes a thermistor 20, the thermistor amplifier circuit 30, the diagnostic system 40, a contactor 42, and the motor 44.

    [0007] The thermistor 20 is configured to generate a signal indicative of a temperature level of the motor 44. The thermistor 20 is disposed proximate to the motor 44 and is electrically coupled between nodes 60, 154 of the diagnostic system 40.

    [0008] The thermistor amplifier circuit 30 is configured to amplify a voltage from the thermistor 20. The thermistor amplifier circuit 30 includes a voltage source 70, an amplifier 72, resistors 74, 76, nodes 78, 79, and a capacitor 80. The voltage source 70 is configured to supply an operational voltage to the thermistor amplifier circuit 30. As shown, a resistor 76 is electrically coupled between the voltage source 70 and the node 78. A resistor 74 is electrically coupled between nodes 76, 79, and the capacitor 80 is electrically coupled between the node 79 and electrical ground. The thermistor amplifier circuit 30 receives a signal from either the thermistor 20 or the diagnostic system 40 and amplifies an amplitude of the received signal and outputs an output voltage that is received by the microprocessor 190.

    [0009] The diagnostic system 40 is configured to apply a test voltage signal to the thermistor amplifier circuit 30 wherein an amplitude of the test voltage signal is indicative of a simulated thermistor temperature value. The diagnostic system 40 is further configured determine an amplitude of an output voltage of the thermistor amplifier circuit 30 and to determine a test temperature value based on the amplitude of the output voltage. The diagnostic system 40 is further configured to determine an inaccuracy value based on the test temperature value and the simulated thermistor temperature value.

    [0010] The diagnostic system 40 includes a transistor 100, a controllable resistor 102, resistors 110, 112, 114, capacitors 130, 132, inductors 140, 142, nodes 148, 150, 152, 154, 156, 160, the microprocessor 190, an input device 199, a memory device 200, and a display device 202.

    [0011] The transistor 100 is electrically coupled in series with the controllable variable resistor 102. In one exemplary embodiment, the transistor 100 is a field-effect transistor. Of course, in alternative embodiments, other types of transistors known to those skilled in the art could be utilized such as a BJT transistor or an IGBT transistor for example. As shown, the transistor 100 has an input terminal (G) also referred to as a gate terminal, a first output terminal (D) also referred to as a drain terminal, and a second output terminal (S) also referred to as a source terminal. The input terminal (G) is coupled to a node 150. The resistor 112 is electrically coupled in parallel with the capacitor 130 between the node 150 and electrical ground; and a resistor 110 is electrically coupled in series between the node 150 and the microprocessor 190. Also, the first output terminal (D) is electrically coupled to the thermistor amplifier circuit 30 via the inductor 142 that is electrically coupled between the node 60 and the node 79.

    [0012] The controllable variable resistor 152 is electrically coupled between the second output terminal (S) and electrical ground. In particular, the controllable variable resistor 152 is electrically coupled between the nodes 152, 154. The inductor 140 is electrically coupled between the nodes 154, 156; and the capacitor 132 and a resistor 114 are electrically coupled in parallel to one another between the node 156 and electrical ground. The controllable variable resistor 102 is configured to have a predetermined resistance in response to receiving a control signal from the microprocessor 190, and further configured to have another predetermined resistance in response to receiving another control signal from the microprocessor 190.

    [0013] Referring to FIGS. 2 and 3, the microprocessor 190 accesses a lookup table 300 stored in the memory device 200 to determine a predetermined resistance value in order to set a resistance of the controllable variable resistor 102 to simulate a desired simulated thermistor temperature value. As shown, the lookup table 300 has records 310, 312, 314 having associated resistance values and stimulated thermistor temperature values. For example, if the microprocessor 190 determines to utilize a simulated thermistor temperature value of 100 degrees Celsius to test the thermistor amplifier circuit 30, the microprocessor 190 would access the record 310 and retrieve the resistance value of 5,000 Ohms. Thereafter, the microprocessor 190 would send a control signal to the controllable variable resistor 102 to set the resistance of the resistor 102 to 5,000 Ohms.

    [0014] The transistor 100 is configured to apply a test voltage signal to the thermistor amplifier circuit 30 in response to receiving a control signal from the microprocessor 190. The amplitude of the test voltage signal is indicative of a simulated thermistor temperature value. It should be noted that the resistance of the controllable resistor 102 determines an amplitude of the control signal applied by the transistor 100 to the thermistor amplifier circuit 30 indicative of a simulated thermistor temperature value.

    [0015] The microprocessor 190 is electrically coupled to the transistor 100, the controllable variable resistor 102, the amplifier 72, the input device 199, the memory device 200, the display device 202, and the contactor 42. The microprocessor 190 is configured to determine an amplitude of an output voltage of the thermistor amplifier circuit 30 and to determine a test temperature value based on the amplitude of the output voltage. In one exemplary embodiment, the microprocessor 190 determines the test temperature value utilizing the following equation: test temperature value = Y x amplitude of output voltage, where Y is an empirically determined value.

    [0016] The microprocessor 190 is further configured to determine an inaccuracy value based on the test temperature value and the simulated thermistor temperature value. In one exemplary embodiment, the inaccuracy value is a percent inaccuracy value which is determined utilizing the following equation: percent inaccuracy value = ((test temperature value - simulated thermistor temperature value) / simulated thermistor temperature value) * 100. Also, the microprocessor 190 is further configured to store the inaccuracy value in the memory device 200 and to induce the display device 202 to display the inaccuracy value thereon.

    [0017] The input device 199 is configured to allow a user to input an acceptable inaccuracy range associated with the inaccuracy value. In one exemplary embodiment, the input device 199 is a keyboard. Of course, in alternative embodiments, the input device 199 could be other types of input devices known to those skilled in the art.

    [0018] The microprocessor 190 is further configured to induce the display device 202 to display a warning message when an inaccuracy value is outside of the acceptable inaccuracy range. Additionally, the microprocessor 190 is configured to generate a control signal to induce the contactor 42 to de-energize the motor 44 when the inaccuracy value is outside of the acceptable inaccuracy range.

    [0019] Referring to FIG. 2, a schematic of an exemplary control signal 208 generated by the microprocessor 190 that is received at the input terminal (G) of the transistor 100 is illustrated. The exemplary control signal 208 is generated during a time interval from T1-T2. The control signal 208 induces the transistor 100 to apply a test voltage signal to the thermistor amplifier circuit 30 indicative of a simulated thermistor temperature value.

    [0020] Also, a schematic of an exemplary output voltage 210 of the thermistor amplifier circuit 30 is illustrated. In this example, the output voltage 210 has a desired amplitude indicating that the thermistor amplifier circuit 30 is operating as desired.

    [0021] Additionally, a schematic of another exemplary output voltage 220 of the thermistor amplifier circuit 30 is illustrated. In this example, the output voltage 220 has an undesired amplitude indicating that the thermistor amplifier circuit 30 has degraded operation.

    [0022] Referring to FIGS. 1 and 4-6, flowchart diagrams for a diagnostic method for the thermistor amplifier circuit 30 will now be explained.

    [0023] At step 350, the controllable variable resistor 100 has a first predetermined resistance in response to receiving a first control signal from the microprocessor 190.

    [0024] At step 352, the transistor 100 applies a first test voltage signal to the thermistor amplifier circuit 30 in response to receiving a second control signal for a first time interval from the microprocessor 190. An amplitude of the first test voltage signal is indicative of a first simulated thermistor temperature value.

    [0025] At step 354, the thermistor amplifier circuit 30 outputs a first output voltage in response to receiving the first test voltage signal.

    [0026] At step 356, the microprocessor 190 determines an amplitude of the first output voltage of the thermistor amplifier circuit 30 and determines a first test temperature value based on the amplitude of the first output voltage.

    [0027] At step 358, the microprocessor 190 determines a first inaccuracy value associated with the first test temperature value based on the first test temperature value and the first simulated thermistor temperature value.

    [0028] At step 359, the microprocessor 190 determines a first corrected temperature value based on the first temperature value and the first inaccuracy value. In one exemplary embodiment, the first inaccuracy value is a first percent inaccuracy value. If the first percent inaccuracy value is a negative number, the first corrected temperature value is calculated utilizing the following equation: first corrected temperature value = first test temperature value + (first percent inaccuracy value / 100 * first test temperature value). Alternately, if the first percent inaccuracy value is a positive number, the first corrected temperature value is calculated utilizing the following equation: first corrected temperature value = first test temperature value - (first percent inaccuracy value / 100 * first test temperature value).

    [0029] At step 360, the microprocessor 190 stores the first inaccuracy value associated with the first test temperature value, and the first corrected temperature value in the memory device 200.

    [0030] At step 362, the display device 202 displays the first inaccuracy value and the first corrected temperature value received from the microprocessor 190.

    [0031] At step 364, the microprocessor 190 makes a determination as to whether the first inaccuracy value is outside of an acceptable inaccuracy range. If the value of step 364 equals "yes", the method advances to step 366. Otherwise, the method advances to step 370.

    [0032] At step 366, the display device 202 displays a first warning message received from the microprocessor 190. After step 366, the method advances to step 368.

    [0033] At step 368, the contactor 42 de-energizes the motor 44 in response to a receiving a third control signal from the microprocessor 190. After step 368, the method advances to step 370.

    [0034] At step 370, the controllable variable resistor 102 has a second predetermined resistance in response to receiving a fourth control signal from the microprocessor 190.

    [0035] At step 372, the transistor 100 applies a second test voltage signal to the thermistor amplifier circuit 30 in response to receiving a fifth control signal for a second time interval from the microprocessor 190. An amplitude of the second test voltage signal is indicative of a second simulated thermistor temperature value.

    [0036] At step 374, the thermistor amplifier circuit 30 outputs a second output voltage in response to receiving the second test voltage signal.

    [0037] At step 376, the microprocessor 190 determines an amplitude of the second output voltage of the thermistor amplifier circuit 30 and determines a second test temperature value based on the amplitude of the second output voltage.

    [0038] At step 378, the microprocessor 190 determines a second inaccuracy value associated with the second test temperature value based on the second test temperature value and the second simulated thermistor temperature value.

    [0039] At step 379, the microprocessor 190 determines a second corrected temperature value based on the second temperature value and the second inaccuracy value.

    [0040] At step 380, the microprocessor 190 stores the second inaccuracy value associated with the second test temperature value, and the second corrected temperature value in the memory device 200.

    [0041] At step 382, the display device 202 displays the second inaccuracy value and the second corrected temperature value received from the microprocessor 190.

    [0042] At step 384, the microprocessor 190 makes a determination as to whether the second inaccuracy value is outside of the acceptable inaccuracy range. If the value of step 384 equals "yes", the method advances to step 386. Otherwise, the method is exited.

    [0043] At step 386, the display device 202 displays a second warning message received from the microprocessor 190. After step 386, the method advances to step 388.

    [0044] At step 388, the contactor 42 de-energizes the motor 44 in response to a receiving a sixth control signal from the microprocessor 190.

    [0045] The diagnostic system 40 and the diagnostic method provide a substantial advantage over other systems and methods. In particular, the diagnostic system and diagnostic method provide a technical effect of utilizing a transistor and a controllable variable resistor to apply a test voltage signal to the thermistor amplifier circuit indicative of a first simulated thermistor temperature value.


    Claims

    1. A diagnostic system (40) for a thermistor amplifier circuit (30) of a motor control system, comprising:

    a transistor (100) being electrically coupled in series with a resistor (102), the transistor (100) having an input terminal, a first output terminal, and a second output terminal, the first output terminal being electrically coupled to the thermistor amplifier circuit (30), the resistor (102) being electrically coupled between the second output terminal and electrical ground;

    the transistor (100) configured to apply a first test voltage signal to the thermistor amplifier circuit (30) in response to receiving a second control signal from a microprocessor (190), an amplitude of the first test voltage signal being indicative of a first simulated thermistor temperature value;

    the microprocessor (190) configured to determine an amplitude of a first output voltage of the thermistor amplifier circuit (30) and to determine a first test temperature value based on the amplitude of the first output voltage; and

    the microprocessor (190) further configured to determine a first inaccuracy value based on the first test temperature value and the first simulated thermistor temperature value, characterized in that:

    the resistor (102) is a controllable variable resistor (102) configured to have a first predetermined resistance in response to receiving a first control signal from the microprocessor (190), to have a second predetermined resistance in response to receiving a fourth control signal from the microprocessor (190), and to have a third predetermined resistance in response to receiving a sixth control signal from the microprocessor (190); and

    the diagnostic system (40) comprises an input device (199) configured to allow a user to input an acceptable inaccuracy range and a display device(202) operably coupled to the microprocessor (190), the display device (202) configured to display the first inaccuracy value and to display a warning message when the first inaccuracy value is outside of the acceptable inaccuracy range.


     
    2. The diagnostic system (40) of claim 1, wherein the transistor (100) is a field-effect transistor, the input terminal is a gate terminal, the first output terminal is a drain terminal, and the second output terminal is a source terminal.
     
    3. The diagnostic system (40) of claim 1, wherein the microprocessor (190) is further configured to store the first inaccuracy value in a memory device (200).
     
    4. The diagnostic system (40) of claim 1, further comprising a contactor (42) configured to de-energize a motor (44) in response to receiving a third control signal from the microprocessor (190) when the first inaccuracy value is outside of the acceptable inaccuracy range.
     
    5. The diagnostic system (40) of claim 1, wherein the first inaccuracy value is a first percent inaccuracy value, microprocessor (190) further configured to determine the first percent inaccuracy value utilizing the following equation: first percent inaccuracy value = ((first test temperature value - first simulated thermistor temperature value) / first simulated thermistor temperature value) * 100.
     
    6. The diagnostic system (40) of claim 1, wherein the microprocessor (190) is further configured to determine the first simulated thermistor temperature value by accessing a lookup table (300).
     
    7. The diagnostic system (40) of claim 1, wherein:

    the transistor (100) further configured to apply a second test voltage signal to the thermistor amplifier circuit (30) in response to receiving a fifth control signal from the microprocessor (190), an amplitude of the second test voltage signal being indicative of a second simulated thermistor temperature value;

    the microprocessor (190) further configured to determine an amplitude of a second output voltage of the thermistor amplifier circuit (30) and to determine a second test temperature value based on the amplitude of the second output voltage; and

    the microprocessor (190) further configured to determine a second inaccuracy value based on the second test temperature value and the second simulated thermistor temperature value.


     


    Ansprüche

    1. Diagnosesystem (40) für einen Thermistorverstärkerstromkreis (30) eines Motorsteuersystems, umfassend:

    einen Transistor (100), der mit einem Widerstand (102) elektrisch in Reihe geschaltet ist, wobei der Transistor (100) einen Eingangsanschluss, einen ersten Ausgangsanschluss, und einen zweiten Ausgangsanschluss aufweist, wobei der erste Ausgangsanschluss mit dem Thermistorverstärkerstromkreis (30) elektrisch gekoppelt ist, wobei der Widerstand (102) zwischen dem zweiten Ausgangsanschluss und der elektrischen Masse elektrisch gekoppelt ist;

    dass der Transistor (100) konfiguriert ist, um als Reaktion auf das Empfangen eines zweiten Steuersignals von einem Mikroprozessor (190) ein erstes Testspannungssignal an dem Thermistorverstärkerstromkreis (30) anzulegen, wobei eine Amplitude des ersten Testspannungssignals für einen ersten simulierten Thermistortemperaturwert bezeichnend ist;

    dass der Mikroprozessor (190) konfiguriert ist, um eine Amplitude einer ersten Ausgangsspannung des Thermistorverstärkerstromkreises (30) zu bestimmen und um einen ersten Testtemperaturwert auf Grundlage der Amplitude der ersten Ausgangsspannung zu bestimmen; und

    dass der Mikroprozessor (190) ferner konfiguriert ist, um einen ersten Ungenauigkeitswert auf Grundlage des ersten Testtemperaturwerts und des ersten Thermistortemperaturwerts zu bestimmen, dadurch gekennzeichnet, dass:

    der Widerstand (102) ein steuerbarer variabler Widerstand (102) ist, der konfiguriert ist, um als Reaktion auf das Empfangen eines ersten Steuersignals von dem Mikroprozessor (190) einen ersten vorgegebenen Widerstand aufzuweisen, um als Reaktion auf das Empfangen eines vierten Steuersignals von dem Mikroprozessor (190) einen zweiten vorgegebenen Widerstand aufzuweisen, und um als Reaktion auf das Empfangen eines sechsten Steuersignals von dem Mikroprozessor (190) einen dritten vorgegebenen Widerstand aufzuweisen; und

    das Diagnosesystem (40) eine Eingabevorrichtung (199), die konfiguriert ist, um es einem Benutzer zu ermöglichen, einen akzeptablen Ungenauigkeitsbereich einzugeben und eine Anzeigevorrichtung (202) umfasst, die mit dem Mikroprozessor (190) wirkgekoppelt ist, wobei die Anzeigevorrichtung (202) konfiguriert ist, um den ersten Ungenauigkeitswert anzuzeigen und um eine Warnmeldung anzuzeigen, wenn sich der erste Ungenauigkeitswert außerhalb des akzeptablen Ungenauigkeitsbereichs befindet.


     
    2. Diagnosesystem (40) nach Anspruch 1, wobei der Transistor (100) ein Feldeffekttransistor ist, der Eingangsanschluss ein Gate-Anschluss ist, der erste Ausgangsanschluss ein Drain-Anschluss ist, und der zweite Ausgangsanschluss ein Source-Anschluss ist.
     
    3. Diagnosesystem (40) nach Anspruch 1, wobei der Mikroprozessor (190) ferner konfiguriert ist, um den ersten Ungenauigkeitswert in einer Speichervorrichtung (200) zu speichern.
     
    4. Diagnosesystem (40) nach Anspruch 1, ferner umfassend ein Schütz (42), das konfiguriert ist, um einen Motor (44) als Reaktion auf das Empfangen eines dritten Steuersignals von dem Mikroprozessor (190) abzuschalten, wenn sich der erste Ungenauigkeitswert außerhalb des akzeptablen Ungenauigkeitsbereichs befindet.
     
    5. Diagnosesystem (40) nach Anspruch 1, wobei der erste Ungenauigkeitswert ein Ungenauigkeitswert mit einem ersten Prozentwert ist, wobei der Mikroprozessor (190) ferner konfiguriert ist, um den Ungenauigkeitswert mit einem ersten Prozentwert unter Verwendung der folgenden Gleichung zu bestimmen: Ungenauigkeitswert mit einem ersten Prozentwert = ((erster Testtemperaturwert - erster simulierter Thermistortemperaturwert) / erster simulierter Thermistortemperaturwert) * 100.
     
    6. Diagnosesystem (40) nach Anspruch 1, wobei der Mikroprozessor (190) ferner konfiguriert ist, um den ersten simulierten Thermistortemperaturwert zu bestimmen, indem er auf eine Suchtabelle (300) zugreift.
     
    7. Diagnosesystem (40) nach Anspruch 1, wobei:

    der Transistor (100) ferner konfiguriert ist, um als Reaktion auf das Empfangen eines fünften Steuersignals von dem Mikroprozessor (190) ein zweites Testspannungssignal an dem Thermistorverstärkerstromkreis (30) anzulegen, wobei eine Amplitude des zweiten Testspannungssignals für einen zweiten simulierten Thermistortemperaturwert bezeichnend ist;

    der Mikroprozessor (190) ferner konfiguriert ist, um eine Amplitude einer zweiten Ausgangsspannung des Thermistorverstärkerstromkreises (30) zu bestimmen und um einen zweiten Testtemperaturwert auf Grundlage der Amplitude der zweiten Ausgangsspannung zu bestimmen; und

    der Mikroprozessor (190) ferner konfiguriert ist, um einen zweiten Ungenauigkeitswert auf Grundlage des zweiten Testtemperaturwerts und des zweiten simulierten Thermistortemperaturwerts zu bestimmen.


     


    Revendications

    1. Système de diagnostic (40) pour un circuit amplificateur à thermistance (30) d'un système de commande de moteur, comprenant :

    un transistor (100) qui est couplé électriquement en série avec une résistance (102), le transistor (100) ayant une borne d'entrée, une première borne de sortie et une deuxième borne de sortie, la première borne de sortie étant électriquement couplée au circuit amplificateur à thermistance (30), la résistance (102) étant électriquement couplée entre la deuxième borne de sortie et la masse électrique ;

    le transistor (100) étant configuré pour appliquer un premier signal de tension de test au circuit amplificateur à thermistance (30) en réponse à la réception d'un deuxième signal de commande à partir d'un microprocesseur (190), une amplitude du premier signal de tension de test indiquant une première valeur de température de thermistance simulée ;

    le microprocesseur (190) étant configuré pour déterminer une amplitude d'une première tension de sortie du circuit amplificateur à thermistance (30) et pour déterminer une première valeur de température de test sur la base de l'amplitude de la première tension de sortie ; et

    le microprocesseur (190) étant en outre configuré pour déterminer une première valeur d'imprécision sur la base de la première valeur de température de test et de la première valeur de température de thermistance simulée, caractérisé en ce que :

    la résistance (102) est une résistance variable pouvant être régulée (102) configurée pour avoir une première résistance prédéterminée en réponse à la réception d'un premier signal de commande à partir du microprocesseur (190), et pour avoir une deuxième résistance prédéterminée en réponse à la réception d'un quatrième signal de commande à partir du microprocesseur (190), et pour avoir une troisième résistance prédéterminée en réponse à la réception d'un sixième signal de commande à partir du microprocesseur (190) ; et

    le système de diagnostic (40) comprend un dispositif d'entrée (199) configuré pour permettre à un utilisateur de saisir une plage d'imprécision acceptable et un dispositif d'affichage (202) couplé de manière fonctionnelle au microprocesseur (190), le dispositif d'affichage (202) étant configuré pour afficher la première valeur d'imprécision et pour afficher un message d'avertissement lorsque la première valeur d'imprécision est en dehors de la plage d'imprécision acceptable.


     
    2. Système de diagnostic (40) de la revendication 1, dans lequel le transistor (100) est un transistor à effet de champ, la borne d'entrée est une borne de grille, la première borne de sortie est une borne de drain, et la deuxième borne de sortie est une borne de source.
     
    3. Système de diagnostic (40) de la revendication 1, dans lequel le microprocesseur (190) est en outre configuré pour stocker la première valeur d'imprécision dans un dispositif de mémoire (200).
     
    4. Système de diagnostic (40) de la revendication 1, comprenant en outre un contacteur (42) configuré pour couper l'alimentation d'un moteur (44) en réponse à la réception d'un troisième signal de commande à partir du microprocesseur (190) lorsque la première valeur d'imprécision est en dehors de la plage d'imprécision acceptable.
     
    5. Système de diagnostic (40) de la revendication 1, dans lequel la première valeur d'imprécision est une première valeur d'imprécision en pourcentage, le microprocesseur (190) étant en outre configuré pour déterminer la première valeur d'imprécision en pourcentage en utilisant l'équation suivante : la première valeur d'imprécision en pourcentage = ((première valeur de température de test - première valeur de température de thermistance simulée) / première valeur de température de thermistance simulée) * 100.
     
    6. Système de diagnostic (40) de la revendication 1, dans lequel le microprocesseur (190) est en outre configuré pour déterminer la première valeur de température de thermistance simulée en accédant à une table de conversion (300).
     
    7. Système de diagnostic (40) de la revendication 1, dans lequel :

    le transistor (100) étant en outre configuré pour appliquer un deuxième signal de tension de test au circuit amplificateur à thermistance (30) en réponse à la réception d'un cinquième signal de commande à partir du microprocesseur (190),

    une amplitude du deuxième signal de tension de test indiquant une deuxième valeur de température de thermistance simulée ;

    le microprocesseur (190) étant en outre configuré pour déterminer une amplitude d'une deuxième tension de sortie du circuit amplificateur à thermistance (30) et pour déterminer une deuxième valeur de température de test sur la base de l'amplitude de la deuxième tension de sortie ; et

    le microprocesseur (190) étant en outre configuré pour déterminer une deuxième valeur d'imprécision sur la base de la deuxième valeur de température de test et de la deuxième valeur de température de thermistance simulée.


     




    Drawing























    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description