JP5587750B2 - Tampering prevention device - Google Patents

Description

  The present invention relates to an apparatus for preventing unauthorized modification of a control unit mounted on an electronic device.

  In a conventional tamper-proof device incorporated in an electronic device, the on / off state of a contact-type switch mechanism provided on the cover that covers the control unit is monitored, and the cover is opened when this switch mechanism is turned on. A device that determines that the control unit has been illegally modified and prohibits the operation of the device is known (see, for example, Patent Document 1).

Japanese Patent No. 3842505

  However, when the above-mentioned conventional tampering prevention device is mounted on a device such as a water heater or a gas stove, the switch mechanism malfunctions due to rust or dirt due to moisture, etc., and the device operates when the lid is opened. May not be prohibited.

  The present invention has been made in view of the above-described circumstances, and provides a tamper-proof device capable of reliably preventing devices such as a water heater and a gas stove from being used in a tampered manner. Let it be an issue.

The tampering prevention device according to the present invention is
An apparatus for preventing unauthorized modification of a device in which a control unit is incorporated in a main body case, and an opening of the main body case facing the control unit is closed by a lid,
A first acceleration sensor that detects vibration of the device main body from the magnitude of each acceleration in a predetermined X-axis direction, Y-axis direction, and Z-axis direction and outputs the vibration to the control unit;
A second acceleration sensor that detects vibration of the lid body from the magnitude of each acceleration in a predetermined X-axis direction, Y-axis direction, and Z-axis direction, and outputs the detected vibration to the control unit;
Whether the correlation between the second output waveform indicating a change in the acceleration in each direction to be outputted from the first output waveform and the second acceleration sensor indicative of the change in the direction of the acceleration output from the first acceleration sensor A vibration determination unit for determining each of the directions ,
When it is detected that there is no correlation between the first output waveform and the second output waveform in at least one of the directions, it is determined that the control unit may be tampered with. And an operation prohibition unit that prohibits the operation of the device,
The control unit is provided with a first acceleration sensor, and the lid is provided with a second acceleration sensor.

In this device, the vibration of the main body of the device and the vibration of the lid are separately detected by the acceleration sensor, and unauthorized modification of the control unit is monitored based on the presence or absence of correlation between these vibrations. hard. Therefore, when it is detected that the control unit may be tampered with, it is possible to accurately prohibit the operation of the device.
In particular, this configuration is configured to monitor unauthorized modification of the control unit based on the presence or absence of correlation of vibrations in the three directions of the X-axis direction, Y-axis direction, and Z-axis direction. It is possible to make it.
Moreover, in this case, since the control unit is provided with the first acceleration sensor and the lid is provided with the second acceleration sensor, the control unit is removed from another location without opening the lid. Also, the vibration of the control unit and the vibration of the lid are detected as having no correlation. Therefore, it is possible to detect from various points that the control unit may be tampered with.

In the above unauthorized tampering prevention device,
A memory for recording an error determination that the uncorrelated state is detected;
A reset unit that erases the record of the error determination when an error cancel operation is performed by the operation unit of the device,
The operation prohibiting unit may cancel the prohibition state when the error determination record is erased.

  In this case, when the operation of the device is prohibited, it is possible to maintain the prohibited state until an error canceling operation is performed even if it is no longer detected that there is a possibility of unauthorized modification.

  As described above, according to the present invention, it is possible to reliably prevent devices such as a water heater and a gas stove from being used in an illegally modified state.

1 is a perspective view of a water heater equipped with an unauthorized modification detection device according to a first embodiment of the present invention. It is a conceptual graph which shows the change of the acceleration detected by each acceleration sensor of the unauthorized modification detection apparatus which concerns on the 1st Embodiment of this invention. It is an operation | movement flowchart at the time of the main electric power supply of the unauthorized modification detection apparatus which concerns on the 1st Embodiment of this invention. It is an operation | movement flowchart which shows the acceleration detection operation | movement of the unauthorized modification detection apparatus which concerns on the 1st Embodiment of this invention. It is an operation | movement flowchart at the time of auxiliary power supply of the unauthorized modification detection apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view of the gas stove carrying the unauthorized modification detection apparatus which concerns on the 2nd Embodiment of this invention. It is a conceptual graph which shows the change of the acceleration detected by each acceleration sensor of the unauthorized modification detection apparatus which concerns on the 2nd Embodiment of this invention. It is an operation | movement flowchart at the time of the main power supply of the unauthorized modification detection apparatus which concerns on the 2nd Embodiment of this invention. It is an operation | movement flowchart at the time of auxiliary power supply of the unauthorized modification detection apparatus which concerns on the 2nd Embodiment of this invention.

Next, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 shows a water heater 1 equipped with a tamper-proof device according to the first embodiment of the present invention. A main body case 10 constituting the outer body of the water heater 1 has a gas burner and a heat (not shown). In addition to the exchanger and the hot / cold water mixing valve, a control unit 11 for controlling the operation of the gas burner, the hot / cold water mixing valve and the like is incorporated.

  Further, in the main body case 10, an auxiliary power supply device 12 for supplying auxiliary power to the control unit 11 when the supply of main power from the power source to the control unit 11 is interrupted, and an unauthorized modification to the control unit 11. A sound output unit 13 capable of outputting an error sound indicating that there is a risk is incorporated.

  A maintenance window 14 facing the control unit 11 is opened in front of the main body case 10. The maintenance window 14 is closed from the front side of the main body case 10 by a rectangular flat maintenance door 15, and the control unit 11 is hidden in the main body case 10 by the maintenance door 15.

  The maintenance door 15 is screwed and fixed to the peripheral portion of the maintenance window 14 so as to be detachable. When maintenance of the water heater 1 is performed, the operator opens the maintenance door 15 to control the maintenance door 15. It becomes possible to operate each switch 111 provided on the front portion of the unit 11 and to repair and inspect a safety device, an electric circuit, etc. (not shown).

  On the front part of the control unit 11, maintenance switches 111 such as a test operation start switch, a gas type setting switch, an error call switch, an error reset switch, etc., and an error code indicating that the control unit 11 may be tampered with. The display unit 112 capable of displaying is provided.

  The control unit 11 includes an X-axis direction component of acceleration caused by vibration (hereinafter referred to as “X-axis direction acceleration X1”) and a Y-axis direction component size (hereinafter referred to as “Y-axis direction acceleration Y1”). And a first acceleration sensor 16 that detects vibration of the water heater 1 main body from the magnitude of the Z-axis direction component (hereinafter referred to as “acceleration Z1 in the Z-axis direction”).

  The first acceleration sensor 16 has an X-axis direction corresponding to the left-right direction of the main body case 10, a Y-axis direction corresponding to the vertical direction of the main body case 10, and a Z-axis direction corresponding to the front-back direction of the main body case 10. It is arranged so that. That is, the acceleration X1 in the X axis direction increases or decreases in accordance with the magnitude of the horizontal shaking of the water heater 1 body, and the acceleration Y1 in the Y axis direction increases to the magnitude of the vertical shaking of the water heater 1 body. The acceleration Z1 in the Z-axis direction is set so as to increase or decrease in accordance with the magnitude of shaking in the front-rear direction of the water heater 1 body. Here, the rightward direction, upward direction, and forward direction of the main body case 10 are detected as positive acceleration values, and the leftward direction, downward direction, and backward direction are detected as negative acceleration values.

  On the other hand, on the rear surface of the maintenance door 15, the magnitude of the X-axis direction component of acceleration caused by vibration (hereinafter referred to as “acceleration X2 in the X-axis direction”) and the magnitude of the Y-axis direction component (hereinafter referred to as “Y-axis direction”). And a second acceleration sensor 17 for detecting the vibration of the maintenance door 15 from the magnitude of the component in the Z-axis direction (hereinafter referred to as “acceleration Z2 in the Z-axis direction”). ing.

  In the second acceleration sensor 17, the X-axis direction corresponds to the left-right direction of the maintenance door 15, the Y-axis direction corresponds to the up-down direction of the maintenance door 15, and the Z-axis direction corresponds to the front-rear direction of the maintenance door 15. It is arranged so that. That is, the X-axis acceleration X2 increases or decreases in accordance with the horizontal swing of the maintenance door 15, and the Y-axis acceleration Y2 matches the vertical swing of the maintenance door 15. The acceleration Z2 in the Z-axis direction is set to increase or decrease in accordance with the magnitude of the shaking of the maintenance door 15 in the front-rear direction. Here, the left side direction, the upper side direction, and the rear side direction of the maintenance door 15 are detected as positive accelerations, and the right side direction, the lower side direction, and the front side direction are detected as negative accelerations.

  The first acceleration sensor 16 and the second acceleration sensor 17 are integrally packaged with a movable part that is displaced by an inertial force of vibration and a displacement detection part that detects a capacitance that changes in accordance with the displacement of the movable part. This chip device is less susceptible to moisture and dirt than the conventional contact-type switch mechanism described above, but it is entirely covered with a highly waterproof potting material in order to further improve moisture resistance and dirt resistance. Has been.

  Although not shown, the control unit 11 performs a predetermined time of each acceleration in the X-axis, Y-axis, and Z-axis directions detected by the hot water supply operation execution unit that supplies hot water to the hot water supply destination and the first acceleration sensor 16 ( Here, a change in 0.1 second (hereinafter referred to as “first output waveform”) and a predetermined time (here, each acceleration in the X-axis, Y-axis, and Z-axis directions detected by the second acceleration sensor 17). , 0.1 second) (corresponding to the “second output waveform”) correlation coefficient calculation unit for calculating the correlation coefficient separately, and whether each of the correlation coefficients is within a predetermined reference range. Vibration determining unit for determining whether or not, memory for recording at least one of the above correlation coefficients within a reference range as an error determination, operation prohibiting unit for prohibiting hot water supply operation when there is an error determination record in the memory Error in memory A notification control unit for outputting an error sound and displaying an error code when there is a record, a reset unit for erasing the error determination when an error canceling operation described later is performed, and a point from when the error determination is canceled The timer is configured to measure the elapsed time.

  In the first embodiment, the first output waveform in the X-axis direction and the second output waveform in the X-axis direction, the first output waveform in the Y-axis direction and the second output waveform in the Y-axis direction, and Z The first output waveform in the axial direction is set to be compared with the second output waveform in the Z-axis direction (see FIG. 2).

  The correlation coefficient between each of the first output waveform and the second output waveform is determined by the two acceleration sensors according to the installation directions of the first acceleration sensor 16 and the second acceleration sensor 17, as will be described later. It is calculated based on the corresponding acceleration in each axial direction. Specifically, the covariance between the acceleration per unit time detected by the first acceleration sensor 16 and the acceleration per unit time detected by the second acceleration sensor 17 in a predetermined time is calculated, and the covariance is calculated. Is divided by the product of each standard deviation of the acceleration.

[Actual operation of detection of unauthorized modification in the first embodiment]
Next, the unauthorized modification detection operation of the water heater 1 by the control unit 11 will be described according to the operation flowcharts of FIGS.
First, when the main power is turned on and main power is supplied to the control unit 11, as shown in FIG. 3, it is checked whether or not the above-described error determination is recorded in the memory (ST1).

  At this time, if no error determination is recorded in the memory (No in step ST1), the first acceleration sensor 16 and the second acceleration sensor 17 cause the acceleration X1 in each X-axis direction per unit time in a predetermined time. X2, accelerations Y1 and Y2 in the Y-axis direction, and accelerations Z1 and Z2 in the Z-axis direction are detected (ST2).

  The acceleration detection operation in step ST2 will be described in detail. As shown in FIG. 4, first, the acceleration X1 in the X-axis direction of the first acceleration sensor 16 per predetermined unit time (here, 2/1000 second). , Y-axis direction acceleration Y1, Z-axis direction acceleration Z1, and second acceleration sensor 17 X-axis direction acceleration X2, Y-axis direction acceleration Y2, Z-axis direction acceleration Z2 are detected separately, 1 is added to and stored in the count i indicating the number of times the acceleration is detected (ST2-1 to ST2-2). Then, it is determined whether or not the count i has reached a predetermined value (here, 50). As a result, if the count i has not reached the predetermined value, the above ST2-1 to ST2-2 are performed again. Steps are executed (ST2-3). In this way, the steps from ST2-1 to ST2-3 are repeated, and if the count i reaches a predetermined value, that is, if a predetermined time (here, 0.1 second) elapses after the acceleration detection operation is started ( In step ST2-3, Yes), the count i is reset to 0, and the acceleration detection operation in the predetermined time is ended (ST2-4).

  Then, as shown in FIG. 3, based on the X-axis direction acceleration X1 of the first acceleration sensor 16 and the X-axis direction acceleration X2 of the second acceleration sensor 17 detected in the step ST2. The correlation number R (X1, X2) is calculated based on the Y-axis acceleration Y1 of the first acceleration sensor 16 and the Y-axis acceleration Y2 of the second acceleration sensor 17. And the correlation coefficient R (Z1, Z2) based on the Z-axis direction acceleration Z1 of the first acceleration sensor 16 and the Z-axis direction acceleration Z2 of the second acceleration sensor 17, respectively, by the calculation method described above. Calculate (ST3).

  Next, whether or not the correlation coefficient R (X1, X2) calculated in step ST3 is within the negative correlation determination reference range (here, −0.6 or more), whether or not the correlation coefficient R (Y1, Y2) is within the positive correlation criterion range (here, 0.6 or less), and the correlation coefficient R (Z1, Z2) is within the negative correlation criterion range (here, −0). .6 or higher) and if any of the correlation coefficients is not within the above-mentioned reference range, the vibration of the water heater 1 and the vibration of the maintenance door 15 are correlated, that is, maintenance. Since the vibration of the door 15 coincides with the vibration of the main body of the water heater 1 (see FIG. 2A), the maintenance door 15 is not opened and there is a possibility that the control unit 11 may be tampered with. Not recognized. Therefore, in this case, it is determined whether or not there is an instruction for hot water supply operation, specifically, whether or not the flow rate of water supplied to a heat exchanger (not shown) exceeds a reference value (ST4 to ST7).

  And when there is no instruction | indication of the said hot water supply operation | movement (it is No at step of ST7), the step after ST2 mentioned above is performed again. Thus, steps ST2 to ST7 described above are repeated, and if there is an instruction for hot water supply operation during that time (Yes in step ST7), hot water operation control such as hot water temperature adjustment is performed according to the set conditions as normal. (ST8).

  On the other hand, if at least one of the above-described correlation coefficients falls within the reference range while repeating steps ST2 to ST7 (for example, Yes in step ST6), vibration of the water heater 1 main body and the maintenance door 15 Since the vibration of the maintenance door 15 does not coincide with the vibration of the main body of the water heater 1 (see FIG. 2B), the maintenance door 15 has been opened, or The control unit 11 may have been removed. Therefore, in this case, it is assumed that there is a possibility of unauthorized modification, and after recording the error determination in the memory, whether or not there is an instruction for a hot water supply operation, and an error canceling operation (for example, an error call switch and an error reset switch) by the switch 111 Are simultaneously pressed for 5 seconds) (ST9 to ST11).

  Thereafter, when an error canceling operation is performed while repeating the steps ST10 and ST11 (Yes in ST11 step), the error determination stored in the memory is erased and a predetermined time has elapsed since the error canceling operation was performed. After the elapse of 30 seconds (here, 30 seconds), the above-described steps after ST1 are executed again (ST12 to ST13).

  On the other hand, if there is an instruction for hot water supply operation while repeating steps ST10 and ST11 (Yes in step ST10), an error sound is output from the audio output unit 13 and an error code is displayed on the display unit 112. Then, the control unit 11 is notified that there is a risk of unauthorized modification, and the hot water supply operation is prohibited from being executed, and the operation is terminated (ST14).

  By the way, when the maintenance of the water heater 1 is performed, the operator may turn off the main power in advance. In this case, the control unit 11 performs the unauthorized modification detection operation by the auxiliary power supplied from the auxiliary power supply device 12. Run.

  Specifically, when the main power supply is turned off and supply of main power to the control unit 11 is interrupted, auxiliary power is supplied from the auxiliary power supply device 12 to the control unit 11. Then, as shown in FIG. 5, the control unit 11 that has received this auxiliary power supplies first each X axis by the first acceleration sensor 16 and the second acceleration sensor 17 in the same manner as in step ST2 described above. Direction accelerations X1 and X2, Y-axis direction accelerations Y1 and Y2, Z-axis direction accelerations Z1 and Z2 are detected, and correlation coefficients R (X1, X2), R are detected as in step ST3 described above. (Y1, Y2) and R (Z1, Z2) are respectively calculated (ST21 to ST22).

  Then, as in the above-described steps ST4 to ST6, it is determined whether or not each correlation coefficient R (X1, X2), R (Y1, Y2), R (Z1, Z2) is within the reference range. (ST23 to ST25).

  Here, if none of the above correlation coefficients is within the reference range (No in steps ST23 to ST25), the vibration of the water heater 1 main body and the vibration of the maintenance door 15 are in a correlated state. The steps from ST21 to ST25 are repeated again assuming that there is no possibility of modification. However, when at least one of the above correlation coefficients falls within the reference range (for example, Yes in step ST25), the vibration of the water heater 1 main body and the vibration of the maintenance door 15 are not correlated. If there is a risk of unauthorized modification, an error determination is recorded in the memory and the operation is terminated (ST26).

  Therefore, after that, when the main power supply is turned on and the error determination record is checked in the above-described step ST1, the error determination is recorded in the memory (Yes in the step ST1). Steps after ST11 are performed.

  As described above, according to the unauthorized modification preventing device according to the first embodiment, the vibration of the water heater 1 and the vibration of the maintenance door 15 are detected separately by the two acceleration sensors 16 and 17, and the vibrations are detected. Since the control unit 11 determines whether or not the control unit 11 may be illegally modified depending on the presence or absence of the correlation, the control unit is illegally controlled by the on / off state of the switch mechanism as in the conventional unauthorized modification prevention device described above. It is less susceptible to moisture and dirt than a configuration that monitors modification. Therefore, when it is detected that the control unit 11 may be tampered with, it is possible to accurately prohibit the hot water supply operation. Thereby, it can prevent reliably that the water heater 1 is used in the state modified | changed illegally.

In particular, this configuration is configured to monitor unauthorized modification of the control unit 11 based on the presence or absence of correlation of vibrations in the three directions of the X-axis direction, the Y-axis direction, and the Z-axis direction. It can be prohibited. In addition, in this configuration, since the vibration of the main body of the water heater 1 and the vibration of the maintenance door 15 are separately detected by the two acceleration sensors 16 and 17, the entire water heater 1 is caused by an earthquake or shaking during operation. It is possible to accurately detect whether it is vibrating or whether the maintenance door 15 is opened. Thereby, it can prevent more reliably that the water heater 1 is used in the state where it modified illegally.

  Further, the first acceleration sensor 16 is incorporated in the control unit 11 and the second acceleration sensor 17 is fixed to the rear surface of the maintenance door 15, so that the control unit 11 can be removed from another place without opening the maintenance door 15. In this case, since the vibration of the control unit 11 and the vibration of the maintenance door 15 are detected as having no correlation, it is possible to detect in a multifaceted manner that the control unit 11 may be tampered with. is there. Thereby, it can prevent more reliably that the water heater 1 is used in the state where it modified illegally.

  In addition, when the hot water supply operation is prohibited by the control configuration (see steps ST10 to ST12) in which the hot water supply operation prohibition state is canceled when an error cancel operation is performed, the control unit 11 is illegally operated thereafter. Even if it is no longer detected that there is a possibility of modification, the prohibited state can be maintained until an error canceling operation is performed. Thereby, it can prevent more reliably that the water heater 1 is used in the state where it modified illegally.

  In addition, when an error canceling operation is performed, after waiting for a predetermined time to elapse, a control configuration (ST11) that resumes monitoring whether there is a correlation between the vibration of the water heater 1 main body and the vibration of the maintenance door 15 or not. From step ST13 to step ST13), since a predetermined grace period is given from when the error release operation is performed until the maintenance door 15 is closed, convenience is also good.

[Second Embodiment]
FIG. 6 shows a gas stove 2 equipped with a tamper-proof device according to the second embodiment of the present invention. In a main body case 20 constituting the outer body of the gas stove 2 body, a stove burner 2A and a grill burner (not shown) are shown. In addition to the gas regulating valve, a control unit 21 for controlling the operation of the stove burner 2A, grill burner, gas regulating valve and the like is incorporated.

  Further, in the main body case 20, an auxiliary power supply device 22 for supplying auxiliary power to the control unit 21 when the supply of main power from the power source to the control unit 21 is cut off, and the control unit 21 are tampered with. A sound output unit 23 capable of outputting an error sound indicating that there is a risk is incorporated.

  On the upper surface of the main body case 20, an opening 24 is provided where the burner 2 </ b> A and the control unit 21 face. The opening 24 is closed from above by a rectangular flat plate top plate 25, and the control unit 21 is concealed in the main body case 20 by the top plate 25.

  The top plate 25 is fitted to the periphery of the opening 24 from above, and when performing maintenance on the gas stove 2, the operator removes the top plate 25 so that the safety unit (not shown) of the control unit 21 is shown. It is possible to perform repairs and inspections of electrical circuits and the like.

  An operation panel 200 having an opening / closing mechanism, a power switch 201, and a stove ignition switch 202 are provided on the front surface of the main body case 20, and the operation panel 200 further includes a rice cooking switch, a water heater switch, a frying switch, and a stove timer setting. Switches 211 for operation setting such as a switch and a grill timer setting switch, and a display unit 212 capable of displaying an error code indicating that the control unit 21 may be tampered with are arranged.

  Similarly to the control unit 11 of the water heater 1 described above, the control unit 21 uses the X-axis direction acceleration X1, the Y-axis direction acceleration Y1, and the Z-axis direction acceleration Z1 generated by vibrations to vibrate the gas stove 2 body. A first acceleration sensor 26 for detecting the above is incorporated.

  The first acceleration sensor 26 has an X-axis direction corresponding to the front-rear direction of the main body case 20, a Y-axis direction corresponding to the upper-lower direction of the main body case 20, and a Z-axis direction corresponding to the left-right direction of the main body case 20. It is arranged so that. That is, the acceleration X1 in the X-axis direction increases or decreases according to the magnitude of the back and forth shaking of the gas stove 2 body, and the acceleration Y1 in the Y-axis direction matches the magnitude of the up-and-down shaking of the gas stove 2 body. The acceleration Z1 in the Z-axis direction is set so as to increase or decrease in accordance with the magnitude of the horizontal movement of the gas stove 2 body. Here, the forward direction, the leftward direction, and the upward direction of the main body case 20 are detected as positive accelerations, and the backward direction, the rightward direction, and the downward direction are detected as negative accelerations.

  On the other hand, similarly to the maintenance door 15 of the water heater 1 described above, the X-axis direction acceleration X2, the Y-axis direction acceleration Y2, and the Z-axis direction acceleration Z2 are generated on the lower surface of the hot water heater 1 from the A second acceleration sensor 27 for detecting the vibration of the top plate 25 is fixed.

  In the second acceleration sensor 27, the X-axis direction corresponds to the left-right direction of the top plate 25, the Y-axis direction corresponds to the front-back direction of the top plate 25, and the Z-axis direction corresponds to the up-down direction of the top plate 25. It is arranged so that. That is, the acceleration X2 in the X-axis direction increases or decreases in accordance with the magnitude of the horizontal shaking of the top board 25, and the acceleration Y2 in the Y-axis direction matches the magnitude of the shaking of the top board 25 in the front-rear direction. The acceleration Z2 in the Z-axis direction is set so as to increase or decrease in accordance with the magnitude of the vertical shaking of the top board 25. Here, the left side direction, rear side direction, and bottom surface direction of the top plate 25 are detected as positive accelerations, and the right side direction, front side direction, and top surface direction are detected as negative accelerations.

  As with the first acceleration sensor 16 and the second acceleration sensor 17 of the water heater 1 described above, the first acceleration sensor 26 and the second acceleration sensor 27 are chips in which a movable part and a displacement detection part are integrally packaged. The device is entirely covered with a highly waterproof potting material.

  Although not shown, the control unit 21 performs a predetermined time of each acceleration in the X-axis, Y-axis, and Z-axis directions detected by the heating operation execution unit by the stove burner 2A and the grill burner (not shown) and the first acceleration sensor 26 (here. Then, a change in 0.1 second (hereinafter referred to as “first output waveform”) and a predetermined time of each acceleration detected in the X-axis, Y-axis, and Z-axis directions detected by the second acceleration sensor 27 (here, A correlation coefficient calculation unit for calculating a correlation coefficient with a change in 0.1 second) (hereinafter referred to as “second output waveform”), and whether each of the correlation coefficients is within a predetermined reference range. A vibration determination unit for determining, a memory for recording that at least one of the above correlation coefficients is within a reference range as an error determination, an operation prohibiting unit for prohibiting a heating operation when there is a record of error determination in the memory, a memo Is constituted by a reset unit such as to clear the error determination when the notification control unit to execute the display output and the error code error sounds, error reset operation to be described later is made when there is a recording error determination.

  In the second embodiment, the first output waveform in the X-axis direction and the second output waveform in the Y-axis direction, the first output waveform in the Y-axis direction and the second output waveform in the Z-axis direction, and Z The first output waveform in the axial direction is set to be compared with the second output waveform in the X-axis direction (see FIG. 7).

  Then, the correlation coefficient between each of the first output waveform and the second output waveform, as described later, depends on the installation direction of the first acceleration sensor 26 and the second acceleration sensor 27, as described above. It is calculated by the same method as in the embodiment.

[Actual operation of detection of unauthorized modification in the second embodiment]
Next, the unauthorized modification detection operation of the gas stove 2 by the control unit 21 will be described according to the operation flowcharts of FIGS.
First, when the power switch 201 is pressed to turn on the main power and the main power is supplied to the control unit 21, as shown in FIG. 8, it is checked whether or not the above error determination is recorded in the memory. (ST31).

  At this time, if there is no error determination record in the memory (No in step ST31), the first acceleration sensor 26 and the second acceleration sensor 27 perform the same as the step ST2 in the first embodiment described above. The X-axis direction accelerations X1 and X2, the Y-axis direction accelerations Y1 and Y2, and the Z-axis direction accelerations Z1 and Z2 are detected every unit time in a predetermined time, and the detected first acceleration sensor 26 based on the X-axis acceleration X1 of the second acceleration sensor 27 and the Y-axis acceleration Y2 of the second acceleration sensor 27, and the Y-axis acceleration Y1 of the first acceleration sensor 26. And the acceleration Z2 in the Z-axis direction of the second acceleration sensor 27, the correlation coefficient R (Y1, Z2), the acceleration Z1 in the Z-axis direction of the first acceleration sensor 26, and the second acceleration sensor 27. The correlation coefficient R (Z1, X2) based on the X-axis direction of the acceleration Z2, calculated by the calculation method, respectively above (ST32~ST33).

  Next, whether or not the correlation coefficient R (X1, Y2) calculated in step ST33 is within the negative correlation determination reference range (here, −0.6 or more), whether or not the correlation coefficient R (Y1, Z2) is within the negative correlation criterion range (here, -0.6 or more), and the correlation coefficient R (Z1, X2) is within the positive correlation criterion range (here, 0). .6 or less), and if none of the correlation coefficients are within the reference range, the vibration of the gas stove 2 body and the vibration of the top plate 25 are correlated, that is, the top plate 25 is in a state where the vibration of the gas stove 1 coincides with the vibration of the gas stove 1 (see FIG. 7A), the top plate 25 is not opened, and there is no possibility that the control unit 21 will be tampered with. Is recognized. Therefore, in this case, it is determined whether or not there is an instruction for a heating operation, specifically, whether or not an ignition operation has been performed by the stove ignition button 202 (ST34 to ST37).

  And when there is no instruction | indication of the said heating operation (it is No at step of ST37), the step after ST32 mentioned above is performed again. In this manner, the above-described steps ST32 to ST37 are repeated, and if there is an instruction for a heating operation during that time (Yes in step ST37), the burner 2A is ignited as normal, and the heating power is adjusted in accordance with the set conditions. The heating operation is controlled (ST38).

  On the other hand, when at least one of the above-described correlation coefficients falls within the reference range while repeating steps ST32 to ST37 (for example, Yes in step ST35), the vibration of the gas stove 2 body and the top plate 25 Since there is no correlation with the vibration, that is, the vibration of the top plate 25 does not coincide with the vibration of the gas stove 2 body (see FIG. 7B), the top plate 25 has been opened or controlled. The unit 21 may have been removed. Therefore, in this case, it is assumed that there is a possibility of unauthorized modification. After recording the error determination in the memory, whether or not there is an instruction for the heating operation, and an error canceling operation by the switch 211 (for example, the plus key of the stove timer setting switch) And the minus key of the grill timer setting switch are simultaneously pressed for 5 seconds) (ST39 to ST41).

  After that, if an error canceling operation is performed while repeating steps ST40 and ST41 (Yes in step ST41), the error determination stored in the memory is erased, and the above-described steps ST32 and subsequent steps are repeated again ( ST42).

  On the other hand, when there is an instruction for the heating operation (Yes in step ST40), there is a possibility that the control unit 21 may be tampered with due to the error sound from the audio output unit 23 and the display of the error code on the display unit 212. When the power switch 201 is pushed and the main power supply is turned off, the operation is terminated (ST43).

  When the main power supply is turned off and the supply of main power to the control unit 21 is interrupted, auxiliary power is supplied from the auxiliary power supply device 22 to the control unit 21. Then, as shown in FIG. 9, the control unit 21 that has received this auxiliary power supplies the X-axis by the first acceleration sensor 26 and the second acceleration sensor 27 in the same manner as in step ST32 described above. Direction accelerations X1 and X2, Y-axis direction accelerations Y1 and Y2, Z-axis direction accelerations Z1 and Z2 are detected, and correlation coefficients R (X1, Y2), R are detected as in step ST33 described above. (Y1, Z2) and R (Z1, X2) are respectively calculated (ST51 to ST52).

  Then, as in the above-described steps ST34 to ST36, it is determined whether or not each correlation coefficient R (X1, Y2), R (Y1, Z2), R (Z1, X2) is within the reference range. (ST53-ST55).

  Here, if none of the above correlation coefficients is within the reference range (No in all steps from ST53 to ST55), the vibration of the gas stove 2 body and the vibration of the top plate 25 are in a state of correlation, so that unauthorized modification Steps ST51 to ST55 are repeated again. However, when at least one of the correlation coefficients is within the reference range (for example, Yes in step ST54), there is no correlation between the vibration of the gas stove 2 body and the vibration of the top plate 25. Since there is a possibility of unauthorized modification, an error determination is recorded in the memory, and the operation is terminated (ST56).

  Therefore, after that, when the main power supply is turned on and the error determination record is checked in the above-described step ST31, the error determination is recorded in the memory (Yes in step ST31). Steps after ST41 are performed.

  As described above, according to the unauthorized modification preventing device according to the second embodiment, the vibration of the gas stove 2 and the vibration of the top plate 25 are detected by the two acceleration sensors 26 and 27, respectively, Since the control unit 21 determines whether or not there is a possibility that the control unit 21 is illegally modified depending on the presence or absence of the correlation, the control unit 21 is illegally modified as in the case of the unauthorized modification prevention device according to the first embodiment described above. When it is detected that there is a risk, the heating operation of the gas stove 2 can be accurately prohibited. Thereby, it is possible to reliably prevent the gas stove 2 from being used in an illegally modified state.

In particular, this configuration is configured to monitor unauthorized modification of the control unit 21 based on the presence or absence of correlation of vibrations in the three directions of the X-axis direction, the Y-axis direction, and the Z-axis direction. It can be prohibited. In addition, in this configuration, since the vibration of the gas stove 2 main body and the vibration of the top plate 25 are separately detected by the two acceleration sensors 26 and 27, the entire gas stove 21 vibrates due to an earthquake or shaking during operation. It is possible to accurately detect whether or not the top plate 25 is opened. As a result, it is possible to more reliably prevent the gas stove 2 from being used in an illegally modified state.

  Further, the first acceleration sensor 26 is incorporated in the control unit 21 and the second acceleration sensor 27 is fixed to the lower surface of the top plate 25, so that it is the same as the unauthorized modification preventing device according to the first embodiment described above. It is possible to detect from various points that the control unit 21 may be illegally modified. As a result, it is possible to more reliably prevent the gas stove 2 from being used in an illegally modified state.

  Further, by adopting a control configuration in which the prohibition of the heating operation is canceled when an error canceling operation is performed (see steps ST40 to ST42), similarly to the unauthorized modification preventing device according to the first embodiment described above, Since the prohibition state of the heating operation can be maintained until the error canceling operation is performed, it is possible to more reliably prevent the gas stove 2 from being used in an illegally modified state.

In each of the above-described embodiments, the two acceleration sensors detect the tampering of the control unit. However, tampering of the control unit is detected by two or more acceleration sensors (for example, the main body case, the lid). Acceleration sensors are provided in various places such as the body, control unit, safety device, etc., and when it is determined that there is no correlation between the vibration detected by one acceleration sensor and the vibration detected by the other acceleration sensor, It may be configured to prohibit the operation). In this case, since it is possible to detect that the control unit is likely to be tampered with in various ways, it is possible to more reliably prevent the device from being used in a tampered state.

  In each of the above embodiments, the electrostatic acceleration sensor that detects the acceleration from the capacitance that changes with the displacement of the movable portion is employed as the first acceleration sensor and the second acceleration sensor. It is not limited to the detection method, it changes with the heat transfer of the resistance type acceleration sensor that detects acceleration from the electrical resistance that changes in proportion to the degree of strain of the piezoresistive part and the fluid enclosed in the casing A thermal fluid type acceleration sensor that detects acceleration from the temperature distribution to be used may be used.

  In the above-described embodiments, the first acceleration sensor and the second acceleration sensor are covered with a potting material to improve their moisture resistance and stain resistance. However, the first acceleration sensor Further, by covering the second acceleration sensor with a highly waterproof rubber cap, a shrink material, a casing having a waterproof structure, etc., their moisture resistance and stain resistance may be enhanced.

  The tampering prevention device described in each of the above embodiments is not limited to a water heater or a gas stove, but is also equipped with a control unit equipped fan heater, bathroom heater / dryer, oven heating cooker, clothes dryer, dishwasher, induction heating It can be applied to equipment such as a cooker (IH cooking heater).

1 ... Water heater (equipment)
10 ... Main body case 11 ... Control unit 13 ... Maintenance door (lid)
14 ... auxiliary power supply 16 ... first acceleration sensor 17 ... second acceleration sensor 2 ... gas stove (device)
20 ... Main body case 21 ... Control unit 23 ... Top plate (lid)
24 ... auxiliary power supply 26 ... first acceleration sensor 27 ... second acceleration sensor

Claims (2)

An apparatus for preventing unauthorized modification of a device in which a control unit is incorporated in a main body case, and an opening of the main body case facing the control unit is closed by a lid,
A first acceleration sensor that detects vibration of the device main body from the magnitude of each acceleration in a predetermined X-axis direction, Y-axis direction, and Z-axis direction and outputs the vibration to the control unit;
A second acceleration sensor that detects vibration of the lid body from the magnitude of each acceleration in a predetermined X-axis direction, Y-axis direction, and Z-axis direction, and outputs the detected vibration to the control unit;
Whether the correlation between the second output waveform indicating a change in the acceleration in each direction to be outputted from the first output waveform and the second acceleration sensor indicative of the change in the direction of the acceleration output from the first acceleration sensor A vibration determination unit for determining each of the directions ,
When it is detected that there is no correlation between the first output waveform and the second output waveform in at least one of the directions, it is determined that the control unit may be tampered with. And an operation prohibition unit that prohibits the operation of the device,
A tampering prevention device, wherein the control unit is provided with a first acceleration sensor, and the lid body is provided with a second acceleration sensor. In the unauthorized modification prevention device according to claim 1,
A memory for recording an error determination that the uncorrelated state is detected;
A reset unit that erases the record of the error determination when an error cancel operation is performed by the operation unit of the device,
The operation prohibition unit is an unauthorized modification prevention device that releases the prohibition state when the record of the error determination is erased.

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