TEMPERATURE MEASURING DEVICE WITH CORE TEMPERATURE SENSOR

Description

[0001] The invention relates to a core temperature sensor comprising an elongated measuring tube with several NTC resistors. The invention also relates to a temperature measuring device comprising such a core temperature sensor and a data processing device, wherein the data processing device is configured to measure the resistance values ​​of at least one NTC resistor and to determine respective temperature values ​​from the resistance values ​​and an associated R / T characteristic. The invention further relates to a cooking appliance comprising a control unit for controlling the cooking operation of the cooking appliance, wherein the cooking appliance can be coupled to a temperature measuring device and the control unit is configured to receive temperature values ​​from the temperature measuring device for controlling the cooking operation.The invention further relates to a set of devices comprising a temperature measuring device and at least one cooking appliance with a cooking chamber to which the temperature measuring device can be connected. The invention also relates to a method for operating a cooking appliance with a temperature measuring device connected to it, in which the temperature measuring device determines respective temperature values ​​and transmits these temperature values ​​to the cooking appliance. The invention is particularly advantageously applicable to household cooking appliances, especially ovens and cooking appliances with a heated surface such as grills, hot stones, etc.

[0002] Core temperature probes of this type, designed for insertion into food to measure its internal temperature, are well known. These probes often use NTC resistors (thermistors) housed within the measuring tube. The measuring tube is typically lance-shaped for easy insertion into the food. Core temperature probes with multiple identical NTC resistors distributed along the measuring tube, so-called "multi-point core temperature probes," are also known. Multi-point core temperature probes allow for temperature measurements at different points along the measuring tube.

[0003] DE 10 2006 024 130 A1 discloses a cooking process probe that can be freely positioned in a baking / cooking chamber and / or at least partially inserted into food being baked / cooked. Between a handle and a temperature sensor located closer to the handle of the cooking process probe, this probe has a stop for measuring the core temperature on a penetration measuring tube of the probe. This stop is fixedly connected to the penetration measuring tube and preferably forms a single unit with the penetration measuring tube of the cooking process probe. Preferably, the stop is designed as a thin, flat body. Between the stop and the handle of the cooking process probe, at least one temperature sensor is provided, positioned in and / or on the penetration measuring tube, which measures the temperature of the airflow in the immediate vicinity of the food being baked / cooked.

[0004] DE 10 2009 019 613 A1 discloses a temperature measuring device for food being cooked, in particular meat, with an elongated, in particular lance-like, temperature probe for insertion into the food being cooked, wherein a first temperature sensor is arranged at a free end region of the temperature probe, by means of which an internal temperature of the food being cooked can be detected, and wherein a second temperature sensor is arranged at an end region of the temperature probe facing away from the free end region, by means of which an ambient temperature can be measured. US 2008043809 A1 discloses a penetration probe for measuring the core temperature of food during baking or grilling.

[0005] However, a disadvantage of NTC resistors is that, due to their logarithmic R / T characteristic, high measurement accuracy and resolution are only achievable within a relatively narrow temperature range for many practical applications. Therefore, if significantly different temperatures are to be measured with an NTC resistor, a comparatively low measurement accuracy across this range must be accepted. One way to achieve high measurement accuracy over a wider temperature range with a temperature-dependent resistor is to use PTC resistors (positive temperature coefficient thermistors), which have a more linear R / T characteristic than NTC resistors. However, PTC resistors are considerably more expensive than NTC resistors.

[0006] It is the TaskThe present invention aims to overcome the disadvantages of the prior art, at least in part, and in particular to provide an inexpensive way to measure temperature using a core temperature sensor, which also yields high measurement accuracies and resolutions for widely separated temperatures.

[0007] This problem is solved according to the features of independent claim 1. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0008] The problem is solved by a temperature measuring device as defined in claim 1.

[0009] This achieves the advantage of enabling the measurement of different, even widely separated, temperature ranges with high accuracy and resolution, since the NTC resistors used and evaluated for temperature determination are those that offer the highest accuracy or the best combination of high accuracy and high resolution for the temperature range being measured. Furthermore, the core temperature sensor remains cost-effective because NTC resistors are readily available and inexpensive.

[0010] Another advantage is that the core temperature sensor can also be used for applications other than core temperature monitoring, where the temperature ranges differ significantly from the typical range for core temperature monitoring (usually 70 °C to 100 °C). In such cases, the core temperature sensor can also be referred to as a combination core temperature sensor.

[0011] The NTC resistor selected for a specific temperature range to be measured corresponds, in particular, to the NTC resistor that exhibits particularly high / highest measurement accuracy or a particularly favorable compromise between measurement accuracy and measurement resolution within that temperature range. Conversely, an NTC resistor can be assigned a temperature range within which this NTC resistor (and no other NTC resistor with a different R / T characteristic) is used for temperature determination. This temperature range is also referred to as the "preferred temperature range" in the following. The preferred temperature range can be defined, for example, during the design of the core temperature probe or a related cooking device.

[0012] NTC resistors with different R / T characteristics therefore have different preferred temperature ranges. These different preferred temperature ranges can overlap or be spaced apart, but they do not, in particular, overlap in order to ensure unambiguous selection of the NTC resistors or R / T characteristics.

[0013] According to the invention, the temperature measuring device comprises at least two NTC resistors exhibiting different R / T characteristics, i.e., different temperature-dependent resistance values ​​R (also referred to as R(T) or RT) for specific temperatures T. The R / T characteristics can be represented as R / T curves (also referred to as R / T characteristic curves) or calculated from the Steinhart-Hart equation or the Beta equation and are resistance-specific. The core temperature sensor can therefore, for example, comprise at least two NTC resistors with different R / T curves.

[0014] It is a further development that the core temperature probe has a handle at one end of the measuring tube. This facilitates handling. It is also a further development that the handle protrudes laterally beyond the measuring tube, which has the advantage that the handle can also serve as a mechanical stop. Furthermore, it is thermally advantageous if electrical or electronic components, apart from the NTC resistors (if present), are located in the area of ​​the handle. At its other, free end, the measuring tube advantageously tapers to a point, which facilitates insertion into food.

[0015] It is a further development that the core temperature probe is equipped for wired or wireless communication with a cooking appliance. This allows the cooking appliance to receive temperature readings from the core temperature probe and use them to control the appliance. In a wired version, the core temperature probe has a wire or cable by which it can be connected to a cooking appliance. The connection via electrical wires offers the advantages of a particularly simple connection, high resistance to interference, and the possibility of supplying the core temperature probe with electrical power via the wires. Alternatively or additionally, the core temperature probe can be equipped with a wireless communication device (e.g., a Bluetooth module) that is configured to communicate with a corresponding communication device on the cooking appliance.

[0016] It is a further development that the core temperature sensor has exactly two NTC resistors with different R / T characteristics. This is particularly cost-effective to implement.

[0017] It is a further development that the core temperature sensor has at least one group, each containing several NTC resistors with the same R / T characteristic, and in particular, several identical NTC resistors. This achieves the advantage that spatially resolved temperature measurement is possible using the NTC resistors belonging to a group. The core temperature sensor can then be used as a multi-point core temperature sensor, at least for the preferred temperature range associated with that group. The multiple NTC resistors of a group can be distributed along the measuring tube.

[0018] This configuration includes a core temperature sensor with at least one group of several NTC resistors, each with the same R / T characteristic, and one NTC resistor with a different R / T characteristic. Compared to the above refinement, this offers the additional advantage of enabling high-precision, non-spatially resolved temperature measurement within the preferred temperature range assigned to each individual NTC resistor.

[0019] One design feature is that the core temperature sensor has at least two groups, each with several NTC resistors of the same R / T characteristic. This achieves the advantage of enabling spatially resolved temperature measurements for several preferred temperature ranges associated with the respective groups.

[0020] It is a further development that the core temperature sensor has NTC resistors with more than two different R / T characteristics. The more NTC resistors with different R / T characteristics, the more preferred temperature ranges can be provided and measured with high accuracy. This, in turn, advantageously expands the possible measurement and application range of the core temperature sensor.

[0021] One embodiment includes at least one NTC resistor with a "first" R / T characteristic for sensing temperatures between 70 °C and 100 °C (i.e., exhibiting its preferred temperature range within this range). This temperature range is particularly advantageous for measuring the core temperature of cooked food, such as meat. A further development involves the use of multiple such NTC resistors, enabling spatially resolved temperature measurement within the food and thus allowing, for example, a particularly accurate determination of the core temperature.

[0022] One embodiment includes at least one additional NTC resistor with a different ("second") R / T characteristic for sensing temperatures above 150 °C, particularly above 180 °C. This offers the advantage that the core temperature probe can also be used as a temperature sensor for accurately measuring high temperatures. Such temperatures could be, for example, the operating temperature of a cooking appliance, such as the cooking chamber temperature of an oven, the temperature of a cooking accessory (e.g., a heated oven divider), and / or the temperature of a heated cooking surface such as a pizza stone, a baking stone, a hot stone, a griddle, a plancha, a teppanyaki grill, etc.

[0023] It is a particularly advantageous design for temperature ranges above 150 °C that at least one NTC resistor exhibiting its preferred temperature range is a glass-encapsulated NTC resistor. This advantageously enables high measurement accuracy even at such high temperatures using cost-effective means.

[0024] The object is solved according to the invention by a temperature measuring device comprising a core temperature sensor as described above and a data processing device, wherein the different R / T characteristics of the temperature sensors of the core temperature sensor can be retrieved by means of the data processing device and the temperature measuring device, in particular the data processing device, is configured to to select an R / T characteristic depending on a specified temperature setpoint, to measure the resistance values ​​of at least one NTC resistor belonging to the selected R / T characteristic, and to determine the respective temperature values ​​from the resistance values ​​and the associated selected R / T characteristic.

[0025] The temperature measuring device can be designed analogously to the core temperature sensor, and vice versa, and has the same advantages.

[0026] The data processing device can be integrated into the core temperature sensor, for example, in the form of a microprocessor, ASIC, or FPGA housed within the core temperature sensor—particularly in its handle. If the data processing device is integrated into the core temperature sensor, the terms temperature measuring device and core temperature sensor can be used synonymously. However, the data processing device can also be a separate device, for example, integrated into a cooking appliance that can be connected to the core temperature sensor via data transmission.

[0027] The fact that the different R / T characteristics are retrievable can include their availability to the data processing device and their use by the data processing device for conversion. For this purpose, the R / T characteristics can be stored in a data memory of the data processing device or in a data memory connected to the data processing device. For example, the data memory can contain various R / T curves as characteristic curves (e.g., in the form of a lookup table) and / or corresponding material-specific Steinhart-Hart coefficients (often denoted by a0, a1, and a3) or material-specific coefficients of the beta equation (e.g., a material constant B or β and a nominal resistance) for different NTC resistors.

[0028] The fact that the temperature measuring device, in particular the data processing device, is configured to select a specific R / T characteristic depending on a predefined temperature setpoint, includes, in particular, that the temperature measuring device—for example, from a cooking appliance connected to it via data transmission—receives a temperature setpoint and selects the R / T characteristic or the associated at least one NTC resistor best suited for this temperature setpoint. The selection can be carried out, for example, by the data processing device checking whether the temperature setpoint falls within a specific preferred temperature range and, if so, selecting the R / T characteristic corresponding to this preferred temperature range. In one variant, if the temperature setpoint does not fall within a preferred temperature range, a specific R / T characteristic can be selected based on a predefined criterion, e.g.,an R / T characteristic whose preferred range is closest to the temperature setpoint.

[0029] The fact that the temperature measuring device, in particular the data processing device, is configured to measure the resistance values ​​of at least one NTC resistor belonging to the selected R / T characteristic includes, in particular, that the resistance values ​​of NTC resistors exhibiting the selected R / T characteristic are specifically, and especially only, measured. The resistance values ​​of other NTC resistors are either ignored or not measured at all. The latter case can be implemented, for example, by allowing a sensor circuit (e.g., comprising an A / D converter) to be individually connected to each of the NTC resistors, but only to those NTC resistors exhibiting the selected R / T characteristic.

[0030] The fact that the temperature measuring device, in particular the data processing device, is configured to determine respective temperature values ​​from the resistance values ​​and the associated selected R / T characteristic includes, in particular, measuring the resistance values ​​of the at least one NTC resistor exhibiting the selected R / T characteristic and using them as input variables to determine the temperature, based on the selected R / T characteristic, e.g., by matching an R / T curve or formulaically using the Steinhart-Hart equation or the Beta equation. The temperature values ​​can then be used to control a cooking appliance, e.g., to trigger an action when a target core temperature is reached, or to set or regulate an operating temperature.

[0031] It is a configuration in which the target temperature is specified or can be specified by a cooking device that is connected to the temperature measuring device (if the data processing device is integrated into the cooking device, only to the core temperature probe).

[0032] It is a further development that the target temperature of the cooking appliance can be automatically preset, e.g. from an automatically running cooking program or recipe.

[0033] It is a further development that the temperature setpoint corresponds to a user-adjustable temperature setpoint on the cooking appliance. The user-adjustable temperature setpoint can already correspond to the value transmitted to the temperature measuring device, in particular the data processing device (e.g., "90 °C" or "200 °C"), or it can be converted by the cooking appliance into a corresponding temperature setpoint (e.g., a "medium" setting to a temperature setpoint of 90 °C and a "well-done" setting to a temperature setpoint of 100 °C, etc., or a "medium-hot" setting to a temperature setpoint of 200 °C, a "very hot" setting to a temperature setpoint of 250 °C, or a specific temperature or cooking level (e.g., from a range "1" to "9" into correspondingly graduated temperature setpoints between 150 °C and 250 °C, etc.)).

[0034] It is also a further development that a user-defined or program-controlled application is converted by the cooking appliance into a temperature setpoint value, e.g., a setting of a cooking operation using a core temperature function into a temperature setpoint value within the most suitable preferred temperature range between 70 °C and 100 °C.

[0035] It is also possible that no specific temperature setpoint value is transmitted to the temperature measuring device, but rather information about the intended function of the core temperature probe is transmitted "indirectly." For example, the cooking appliance can transmit a code (e.g., "0") to the temperature measuring device to activate a core temperature function. Based on this code, the device selects the appropriate R / T characteristic for measuring the core temperature. If, however, the core temperature probe is to be used to measure the operating temperature of a grill or similar appliance, a different code (e.g., "1") is transmitted to the temperature measuring device. Based on this code, the device selects a different R / T characteristic suitable for higher temperatures.

[0036] The problem is also solved by a cooking appliance comprising a control device for controlling a cooking operation of the cooking appliance, wherein the cooking appliance has a temperature measuring device as described above and is configured to transmit a temperature setpoint to the temperature measuring device, and wherein the control device is configured to receive temperature values ​​from the temperature measuring device for controlling the cooking operation.

[0037] The cooking device can be designed analogously to the temperature measuring device and / or the core temperature probe, and vice versa, and has the same advantages.

[0038] The cooking appliance is preferably a household cooking appliance. It is a further development that the cooking appliance has a cooking chamber, e.g., an oven and / or a steamer. It is also a further development that the cooking appliance has or is a heated cooking surface, e.g., a pizza stone, a bread baking stone, a "hot stone," a griddle, a plancha, a teppanyaki grill, etc.

[0039] The target temperature can be, for example, the core temperature of the food being cooked or the operating temperature of the cooking appliance, e.g., the heated cooking surface.

[0040] The target temperature can be set via a user-operated control device such as a rotary knob, button, touch display, etc. Alternatively, the setting device can also be the control unit of the cooking appliance, which sets the target temperature based on user input or a cooking program. Controlling the cooking process can involve comparing the temperature values ​​received from the temperature measuring device with the target temperature or a derived value, for example, to regulate the operating temperature or to monitor whether a core temperature has been reached, etc.

[0041] The problem is further solved by a set of devices comprising a temperature measuring device with a core temperature probe as described above and further comprising at least one cooking device as described above with a cooking chamber (e.g. an oven) and a cooking device as described above with a heated cooking surface (e.g. a grill) which has a receptacle for the measuring tube of the core temperature probe, wherein the cooking devices are designed for coupling with the same temperature measuring device, wherein the cooking device with the cooking chamber is configured to use temperature values ​​received from the core temperature probe to monitor a core temperature of the food being cooked and wherein the cooking device with the heated cooking surface is configured to use temperature values ​​received from the core temperature probe to control an operating temperature of the heated cooking surface.

[0042] The problem can also be solved by a method for operating a cooking appliance as described above, in which a temperature setpoint is transmitted from the cooking appliance to the temperature measuring device, in particular its data processing unit, and the temperature measuring device, in particular its data processing unit, selects an associated R / T characteristic based on the temperature setpoint, senses measured values ​​of at least one NTC resistor belonging to the selected R / T characteristic, determines respective temperature values ​​from these measured values ​​based on the associated R / T characteristic and transmits these temperature values ​​to the cooking appliance.

[0043] The method can be designed analogously to the devices, and vice versa, and has the same advantages.

[0044] The properties, features and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more easily understood in connection with the following schematic description of an exemplary embodiment, which will be explained in more detail in conjunction with the drawings. Fig. 1 shows a sketch of a core temperature sensor according to the invention as a sectional view in side view; Fig. 2 shows a sketch of a sensor circuit and a microprocessor of the core temperature sensor according to the invention; Fig. 3 shows a set with two cooking devices and the core temperature sensor according to the invention; and Fig. 4 shows a possible process sequence according to the invention for operating the core temperature sensor.

[0045] Fig. 1Figure 1 shows a cross-sectional sketch of a multi-point core temperature sensor 1 according to the invention, comprising a lance-shaped measuring tube 2. The front, free end of the tube tapers to a point, while the other, rear end features a handle 3 extending laterally beyond the measuring tube 2. NTC resistors NTC1a, NTC1b, NTC1c, NTC1d, and NTC2 are housed within the measuring tube 2. NTC resistors NTC1a to NTC1d and NTC2 are connected via electrical leads (not shown) to a selection circuit 4, which is connected to a sensor circuit 5. The sensor circuit 5 is in turn connected to a data processing device, for example, a microprocessor 6. The selection circuit 4, the sensor circuit 5, and the microprocessor 6 are housed within the handle 3.

[0046] The selection circuit 4 can be controlled by the microprocessor 6 to connect a specific NTC resistor NTC1a to NTC1d, NTC2 to the sensor circuit 5. The sensor circuit 5 serves to determine the current resistance value R(t) of the connected NTC resistor NTC or NTC1a to NTC1d, NTC2 and to provide this value, as a digitized resistance value R(t), to the microprocessor 6.

[0047] The microprocessor 6 calculates a current temperature value T(t) from the digitized resistance value R(t) and can send it to a cooking device G1 or G2 (see Fig. 3 ) transmit, e.g. wirelessly or - as shown - wired via a cable 7.

[0048] Since the microprocessor 6 is integrated into the core temperature sensor 1 and the core temperature sensor 1 thus outputs currently measured temperature values ​​T(t), the core temperature sensor 1 corresponds to a temperature measuring device.

[0049] Fig. 2shows a sketch of the sensor circuit 5 and the microprocessor 6 of the core temperature sensor 1.

[0050] The microprocessor 6 receives a target temperature value Ttarget from a cooking device G1, G2, which is connected to it at least for data transmission (and possibly also for powering the core temperature sensor 1), via cable 7. Subsequently, an R / T curve RT1 or RT2, or at least a corresponding NTC resistor NTC1a to NTC1d or NTC2, is selected based on at least one predefined criterion. For this purpose, the microprocessor 6 has or is linked to a data memory 6a in which the R / T curves RT1, RT2 are stored (e.g., in a lookup table).

[0051] The R / T curves RT1 and RT2, or the corresponding NTC resistors NTC1a to NTC1d or NTC2, can each be assigned a preferred temperature range VB1 or VB2 in one variant. If the target temperature Ttarget falls within one of the preferred temperature ranges VB1 or VB2, the corresponding R / T curve RT1 or RT2 is selected. The preferred temperature ranges VB1 and VB2 are shown here spaced apart from each other, but can alternatively be adjacent or overlapping.

[0052] If a specific R / T curve RT1 or RT2 has been selected, the selection circuit 4 connects at least one of the NTC resistors corresponding to that R / T curve RT1 or RT2 to the sensor circuit 5. Connecting the NTC resistor can involve connecting the NTC resistor NTC2, which corresponds to the R / T curve RT2, or connecting the NTC resistors NTC1a to NTC1d, which correspond to the R / T curve RT1, alternately over time.

[0053] The sensor circuit 5 comprises a resistive load Rref with a precisely known resistance value, which is connected in series with the NTC resistor NTC. A center tap Vout of this resistor chain Rref, NTC is connected to an input of an analog-to-digital converter (ADC). The NTC resistor NTC is also connected in parallel with a capacitor C. The resistor chain Rref, NTC and the ADC are connected to a voltage Vcc, which corresponds to the operating voltage of the ADC. This allows the sensor circuit 5 to sense the resistance value of the NTC resistor NTC and output it as the current digitized measured value R(t) to the microprocessor 6.

[0054] The microprocessor 6 calculates the current temperature value T(t) from the digitized measured value R(t) based on the selected R / T curve RT1 or RT2 and makes it available to the cooking device G1 or G2 via the cable 7.

[0055] Fig. 3shows a set 1, G1, G2 of devices comprising the core temperature probe 1, a cooking device G1 in the form of an oven and a cooking device G2 in the form of a grill (e.g. a grid grill, raclette grill, hot stone, pizza stone, teppanyaki, etc.).

[0056] The oven G1 has a heated cooking chamber 8 and a control unit 9 for its operation. The control unit 9 is also configured, e.g., programmed, to control a cooking process using the core temperature probe 1. If the core temperature probe 1 is connected to the oven G1, the control unit 9 can, for example, use the current temperature values ​​T(t) transmitted by the core temperature probe 1 to compare them with a core temperature setpoint, which, for example, reflects a desired degree of doneness for the food to be cooked in the cooking chamber 8. If the core temperature probe 1 is connected to the oven G1, the control unit 9 can transmit the core temperature setpoint as the temperature setpoint Tsetpoint to the core temperature probe 1. Since the core temperature setpoint is usually within a temperature range of 70 °C to 100 °C, and this temperature range is, for example,If the preferred temperature range VB1 corresponds to or is contained within VB1, the core temperature sensor 1 selects the associated R / T curve RT1. Using only the NTC resistors NTC1a to NTC1d, the core temperature sensor 1 then functionally corresponds to a multi-point core temperature sensor.

[0057] The grill G2 has a cooking surface 10 that can be heated, for example, by electric heating elements, gas, etc., and which has a receptacle 11 for receiving the measuring tube 2 of the core temperature probe 1. The receptacle 11 can be in the form of, for example, an elongated hole, a blind hole, or another guide. If the measuring tube 2 is inserted into the receptacle 11 (with the handle 3 serving as a stop), the core temperature probe 1 can measure the operating temperature of the heated cooking surface 10. If the core temperature probe 1 is also connected to the grill G2 via the cable 7, the grill G2 can regulate the operating temperature to a setpoint temperature value configured on the grill G2.

[0058] The grill has a control unit 12 which can transmit the operating temperature setpoint as the temperature setpoint Tsetpoint to the core temperature sensor 1. Since the operating temperature setpoint is usually above 150 °C, especially above 180 °C, and thus within the preferred temperature range VB2, which starts, for example, at 150 °C, the core temperature sensor 1 selects the corresponding R / T curve RT2 in this case. Using only the single NTC resistor NTC2, the core temperature sensor 1 then functionally corresponds to a single-point temperature sensor.

[0059] The two cooking devices G1 and G2 are therefore designed for connection to the same core temperature sensor 1, whereby the core temperature sensor 1 fulfills different functions and uses respective NTC resistors NTC2 or groups of them NTC1a to NTC1d for this purpose. In general, the core temperature sensor 1 can also optionally use several NTC resistors with different R / T curves to fulfill a specific function.

[0060] The core temperature setpoint can be set programmatically or by the user via an operating device (here, for example, a rotary knob 13 or similar), for example directly as a temperature value or a corresponding setting such as "through", "medium", "hot", "very hot", a temperature level, etc.

[0061] Fig. 4 shows a possible process sequence according to the invention for operating the core temperature sensor 1 or a cooking device G1 or G2 coupled to it.

[0062] In step S1, the cooking device G1 or G2 sends the target temperature Tsoll via cable 7, which is received in step S2 by the core temperature sensor 1, in particular its microprocessor 6, via cable 7.

[0063] In step S3, the microprocessor 6 selects a corresponding R / T characteristic in the form of an R / T curve RT1 or RT2 based on the temperature setpoint Tsoll using a predefined criterion (e.g. a match with a preferred temperature range VB1, VB2).

[0064] In step S4, for example from a sensor circuit 5, a current resistance value R(t) of at least one NTC resistor NTC or NTC1a to NTC1d or NTC2 belonging to the selected R / T curve RT1 or RT2 is determined.

[0065] In step S5, the microprocessor 6 determines a temperature value T(t) from this resistance value R(t) based on the selected R / T curve RT1 or RT2 and transmits it in step S6 via the cable 7.

[0066] In step S7, the temperature value T(t) is received via cable 7 from the cooking device G1 or G2 and is used, for example, to monitor whether a core temperature has been reached or to control an operating temperature.

[0067] Steps S1 to S7 or S3 to S7 can be repeated at regular intervals.

[0068] Of course, the present invention is not limited to the embodiment shown.

[0069] Instead of R / T curves, Steinhart-Hart or Beta coefficients can also be stored, and a current temperature value T(t) can be calculated using the Steinhart-Hart or Beta formula.

[0070] It is also possible to use more than two R / T curves with correspondingly more than two different NTC resistors or groups thereof.

[0071] In general, "ein", "eine", etc. can be understood to mean singular or plural, especially in the sense of "at least one" or "one or more", etc., unless this is explicitly excluded, e.g. by the expression "exactly one", etc.

[0072] A numerical specification can also include exactly the specified number as well as a normal tolerance range, unless this is explicitly excluded. Reference symbol list

[0073] 1 Core temperature sensor 2 Measuring tube 3 Handle 4 Selection circuit 5 Sensor circuit 6 Microprocessor 6a Data storage 7 Cable 8 Cooking chamber 9 Control unit 10 Heated cooking tray 11 Mounting 12 Control unit 13 Rotary knob ADCA / D converter C Capacitor G1 Cooking appliance / Oven G2 Cooking appliance / Grill NTC resistor NTC1a - NTC1d NTC resistors with R / T curve RT1 NTC2 NTC resistor with R / T curve RT2 R(t) Current resistance value Rref Ohmic resistance RT1 R / T curve RT2 R / T curve S1-S7 Process steps T(t) Current temperature value Tset Temperature setpoint VB1 Preferred temperature range of the R / T curve RT1 VB2 Preferred temperature range of the R / T curve RT2 Vcc Operating voltage of the A / D converter ADC Vout Center tap

Claims

1. Temperature measurement apparatus (1), having - a core temperature sensor (1), which has an elongate measurement tube (2) with multiple NTC resistors (NTC, NTC1a - NTC1d, NTC2), wherein at least two of the NTC resistors (NTC1a - NTC1d, NTC2) have a different R / T characteristic (RT1, RT2) from one another, - as well as a data processing apparatus (6), by means of which the different R / T characteristics (RT1, RT2) of the NTC resistors (NTC1a - NTC1d, NTC2) of the core temperature sensor (1) can be retrieved, wherein the temperature measurement apparatus (1) is configured - to select an R / T characteristic (RT1, RT2) as a function of a predefined temperature setpoint value (Tsetpoint), - to measure resistance values (R(t)) of at least one NTC resistor (NTC1a - NTC1d, NTC2) associated with the selected R / T characteristic (RT1, RT2) and - to determine respective temperature values (T(t)) from the resistance values (R(t)) and the associated selected R / T characteristic (RT1, RT2).

2. Temperature measurement apparatus (1) according to claim 1, wherein the core temperature sensor (1) has at least one group with multiple NTC resistors (NTC1a - NTC1d) in each case with R / T characteristic (RT1) that is the same per group as well as an NTC resistor (NTC2) with R / T characteristic (RT2) that is different therefrom.

3. Temperature measurement apparatus (1) according to one of the preceding claims, wherein the core temperature sensor (1) has at least two groups, each with multiple NTC resistors (NTC1a - NTC1d) with the same R / T characteristic (RT1) per group.

4. Temperature measurement apparatus (1) according to one of the preceding claims, wherein at least one NTC resistor (NTC1a - NTC1d) with a first R / T characteristic (RT1) is provided for sensing temperatures between 70 °C and 100 °C and at least one NTC resistor (NTC2) with a second R / T characteristic (RT2) is provided for sensing temperatures above 150 °C.

5. Temperature measurement apparatus (1) according to one of the preceding claims, wherein at least one NTC resistor (NTC1a - NTC1d) is a glass-encapsulated NTC resistor.

6. Cooking appliance (G1, G2), having a control facility (9, 12) for controlling a cooking operation of the cooking appliance (G1, G2), wherein the cooking appliance (G1, G2) has a temperature measurement apparatus (1) according to one of the preceding claims and is configured to transfer a temperature setpoint value (Tsetpoint) to the temperature measurement apparatus (1), and wherein the control facility (9, 12) is configured to receive temperature values (T(t)) from the temperature measurement apparatus (1) in order to control the cooking operation.

7. Cooking appliance (G1, G2) according to claim 6, wherein the temperature setpoint value (Tsetpoint) corresponds to a temperature setpoint value (Tsetpoint) that can be set by the user on the cooking appliance (G1, G2).

8. Set (G1, G2, 1) of apparatuses, comprising - a cooking appliance (G1) according to at least one of claims 6 to 7 with a cooking compartment (8) as well as - a cooking appliance (G2) according to one of claims 6 to 7 with a heatable cooking base (10), which has a receptacle (11) for the measuring tube (2) of the core temperature sensor (1), wherein - the cooking appliances (G1, G2) are embodied for coupling to the same temperature measurement apparatus (1), - the cooking appliance (G1) with the cooking compartment (8) is configured to use temperature values (T(t)) received from the temperature measurement apparatus (1) to monitor a core temperature of food to be cooked, and - the cooking appliance (G2) with the heatable cooking base (10) is configured to use temperature values (T(t)) received from the core temperature sensor (1) to regulate an operating temperature of the heatable cooking base (10).

9. Method for operating (1) a cooking appliance according to one of claims 6 to 7, in which - a temperature setpoint value (Tsetpoint) is transmitted (S1, S2) from the cooking appliance (G1, G2) to the temperature measurement apparatus (1) and the temperature measurement apparatus (1), - on the basis of the temperature setpoint value (Tsetpoint), selects (S3) an associated R / T characteristic (RT1, RT2), - senses (S4) resistance values (R(t)) of at least one NTC resistor (NTC, NTC1a - NTC1d, NTC2) associated with the selected R / T characteristic (RT1, RT2), - determines (S5) respective temperature values (T(t)) from said resistance values (R(t)) on the basis of the associated R / T characteristic (RT1, RT2) and - transmits (S6, S7) the temperature values (T(t)) to the cooking appliance (G1, G2).