JP3731512B2 - Temperature controller and heat treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention, HiThe present invention relates to a temperature controller that controls temperature by controlling energization of a heater and a heat treatment apparatus including the temperature controller.
[0002]
[Prior art]
  In a heat treatment apparatus, for example, an injection molding machine, a plurality of heaters, for example, three-phase heaters, are attached to the outer peripheral wall of an injection cylinder, and are connected to a common three-phase power source via an SSR or the like to be supplied with power.
[0003]
[Problems to be solved by the invention]
  In such an injection molding machine, a heater disconnection detection circuit is provided to detect the disconnection of the heater. In order to be able to detect any of the three-phase heaters that are disconnected, each three-phase heater is detected. Every time, it is necessary to provide two current sensors and a heater current measuring circuit to which the output of each current sensor is given.
[0004]
  The current sensor requires a CT that couples alternating current with a magnetically coupled transformer, and the heater current measurement circuit measures the output current of the CT only when the SSR that drives the heater is energized. Based on this, it was necessary to provide a function for determining whether or not the heater was disconnected.
[0005]
  As described above, the conventional disconnection detection circuit requires a plurality of current sensors and heater current measurement circuits, and thus has a problem that the configuration is complicated and the cost is high.
[0006]
  The present invention has been made in view of the above points, and an object thereof is to provide a disconnection detection method capable of detecting a disconnection with a simple configuration and at a low cost, and a temperature controller and a heat treatment apparatus suitable for the disconnection detection method. And
[0007]
[Means for Solving the Problems]
  The present invention is configured as follows in order to achieve the above-described object.
[0008]
  That is, the temperature controller of the present invention isA temperature controller that outputs an operation amount so that a deviation between the detected temperature of the control target and the target temperature is eliminated, and a switch that turns on and off the heater that heats the control target is controlled based on the operation amount. In the temperature controller for controlling the temperature of the controlled object by controlling the energization of the heater, the maximum slope of the detected temperature waveform until the detected temperature of the controlled object reaches the target temperature ( Inclination = Change in detected temperature / Change in time ) A breakage detecting means for detecting breakage of the heater based on at least one of a steady gain after settling, the manipulated variable after settling, and the deviation after settling, and the breakage detecting means includes the control Detects normal disturbance corresponding to the input of the workpiece to be heat-treated by the target to the control target In the normal disturbance, detection of disconnection of the heater is prohibited, and the disturbance detection unit includes at least 3 along the moving direction of the workpiece to be controlled in the control target. Detection outputs of a plurality of temperature detection means for detecting the temperature of the control target at two different locations are provided, and the disturbance detection means is configured to perform normal operation based on the temperature difference between the detected temperatures detected at the different locations. It detects disturbances.
[0009]
  According to the present invention, the maximum slope of the detected temperature waveform until the detected temperature of the controlled object reaches the target temperature. ( Inclination = Change in detected temperature / Change in time ) Since the heater breakage is detected based on at least one of the steady gain after settling, the manipulated variable after settling, and the deviation after settling, a conventional current sensor or heater current measuring circuit is required. Instead, the disconnection of the heater can be detected with a simple configuration and at a low cost.
[0010]
  In addition, normal disturbances, for example, fluctuations in temperature, etc., when a workpiece such as a raw material resin or wafer is put into a controlled heating cylinder, hot plate, heat treatment furnace, etc. are detected by the disturbance detection means, and applied. During normal disturbance, detection of heater disconnection is prohibited, so that it is possible to prevent erroneous detection of fluctuations in temperature and the like due to the disturbance as being due to heater disconnection.
[0011]
  In addition, for example, normal disturbance such as charging of the raw material resin based on the temperature distribution (temperature gradient) of the heating cylinder generated when the raw material resin as the object to be processed is charged into the heating cylinder or the like to be controlled. Is detected and the heater disconnection detection is prohibited, so that erroneous detection of the heater disconnection can be prevented.
[0012]
  The temperature controller of the present invention includes a temperature controller that outputs an operation amount so that a deviation between the detected temperature of the control target and the target temperature is eliminated, and a switch that turns on and off the power of the heater that heats the control target. And controlling the temperature of the object to be controlled by controlling the energization of the heater by controlling based on the operation amount, and n ( n is a natural number of 2 or more ) In the temperature controller that controls the energization for each channel by configuring one channel with the heater, the first setting operation amount that is the operation amount at the time of settling and the operation amount when the settling is lost and set again A disconnection detecting means for detecting disconnection of the heater based on a second settling operation amount, wherein the disconnection detecting means is configured such that the second settling operation amount is n / of the first settling operation amount; The heater disconnection is detected on the condition that (n-1) times.
[0013]
  According to the present invention, the first settling operation amount that is the operation amount at the time of settling before the heater is disconnected, and the second settling operation amount that is the operation amount when the heater is disconnected and settling again after being disconnected. Therefore, it is possible to detect the disconnection of the heater with a simple configuration and at a low cost without using a conventional current sensor or a heater current measuring circuit.
[0014]
  In addition, one channel is formed by the n heaters, and energization control is performed for each channel. The disconnection detecting unit is configured such that the second set operation amount is n / (n− of the first set operation amount. 1) A heater disconnection is detected on condition that it has become approximately doubled. For example, in the case of a three-phase heater, that is, when n = 3, if one of the heaters is disconnected, the first after the disconnection is detected. The settling operation amount of 2 is 1 of the first settling operation amount before disconnection. . 5 { = 3 / (3-1) } Since it becomes about double, the heater disconnection can be detected using this as a detection condition.
[0015]
  In a preferred embodiment of the present invention, the disconnection detecting means has the second settling operation amount in a predetermined range centered on n / (n-1) times the first settling operation amount. The predetermined range is determined in advance so as not to include the first settling operation amount in consideration of variations in the heat generation amount of the heater. .
[0016]
  According to this embodiment, for example, the second settling operation amount is set to n / (n of the first settling operation amount in consideration of the variation in the heat generation amount of the three heaters of the three-phase heater and the influence of the mounting position. -1) It is possible to detect a disconnection of the heater on condition that the predetermined range centered on the magnification is obtained.
[0017]
  The temperature controller of the present invention includes a temperature controller that outputs an operation amount so that a deviation between the detected temperature of the control target and the target temperature is eliminated, and a switch that turns on and off the power of the heater that heats the control target. And controlling the temperature of the object to be controlled by controlling the energization of the heater by controlling based on the operation amount, and n ( n is a natural number of 2 or more ) In the temperature controller that controls the energization for each channel by configuring one channel with the heater, the first setting operation amount that is the operation amount at the time of settling and the operation amount when the settling is lost and set again A disconnection detecting means for detecting disconnection of the heater based on a second settling operation amount, wherein the disconnection detecting means is configured such that the second settling operation amount is n / of the first settling operation amount; (N-1) The heater disconnection is detected on condition that the predetermined value is smaller than a predetermined value smaller than (n-1) times. The predetermined value takes into account variations in the amount of heat generated by the heater, and the predetermined value. The above range is determined in advance so as not to include the first settling operation amount.
[0018]
  According to the present invention, for example, when one or more heaters of a three-phase heater are disconnected, it can be detected.
[0019]
  The heat treatment apparatus of the present invention includes a temperature controller that outputs an operation amount so that a deviation between a detected temperature of a control target and a target temperature is eliminated, and a switch that turns on and off a power source of a heater that heats the control target. A heat treatment apparatus comprising: a temperature controller that controls energization of the heater to control the temperature of the control target by controlling based on the amount; and a disconnection detection device that detects disconnection of the heater, The temperature regulator is the maximum slope of the detected temperature waveform until the detected temperature of the controlled object reaches the target temperature. ( Inclination = Change in detected temperature / Change in time ) , At least one of a steady gain after settling, the manipulated variable after settling, and the deviation after settling can be output to the disconnection detection device, and the disconnection detection device is output from the temperature controller. Disturbance detection for detecting a normal disturbance corresponding to the input of an object to be processed that is heat-treated by the control object to the control object based on at least one of the above In the normal disturbance, detection of disconnection of the heater is prohibited, and the disturbance detection means includes at least three different locations along the moving direction of the workpiece to be controlled in the control target. Detection outputs of a plurality of temperature detection means for detecting the temperature of the controlled object are provided, and the disturbance detection means is based on the temperature difference between the detected temperatures detected at the different locations. There are, and detects the normal disturbance.
[0020]
  According to the present invention, the maximum slope of the detected temperature waveform until the detected temperature of the controlled object from the temperature controller reaches the target temperature. ( Inclination = Change in detected temperature / Change in time ) Since the disconnection detector of the computer or the like detects the disconnection of the heater based on at least one of the steady gain after settling, the manipulated variable after settling, and the deviation after settling, the conventional current It is possible to detect the disconnection of the heater with a simple configuration and at a low cost without requiring a sensor or a heater current measuring circuit.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
  First, prior to the description of the embodiment, a configuration for disconnection detection which is the premise thereof will be described as a reference example.
[0023]
  (Reference example 1)
  FIG.Heat treatment system to which heater break detection is appliedIt is a schematic block diagram.
[0024]
  A plurality of heaters 3 are attached to the outer peripheral wall of the injection cylinder 2 of the injection molding machine 1.As a switchIt is connected to a common AC power source 5 via the SSR 4. The injection cylinder 2 is provided with a temperature sensor 6 that detects the temperature of the cylinder 2, and the temperature sensor 6 and the SSR 4 are connected to a temperature regulator 7 that controls the temperature of the injection cylinder 2. Yes. The temperature controller 7 controls the energization of the heater 3 by giving an operation amount MV to the SSR 4 so that the detected temperature (current temperature) PV from the temperature sensor 6 becomes a target temperature (set temperature). is there.
[0025]
  Reference numeral 8 denotes a host computer that controls the entire injection molding machine such as mold clamping and injection. A temperature controller 7 is connected to the host computer 8 and can communicate with the temperature controller 7. Has been.
[0026]
  In this embodiment, in order to detect a disconnection of the heater 3 with a simple configuration and at a low cost without providing a current sensor such as a CT or a heater current measurement circuit, the following configuration is provided. Yes.
[0027]
  2A is a diagram showing a change in the manipulated variable MV at the time of raising the temperature from the room temperature to the target temperature, and FIG. 2B is a diagram showing a change in the detected temperature PV at the normal time. FIG. (C) is a diagram showing changes in the detected temperature PV when the heater break occurs,Detected temperature waveform during temperature riseMaximum slope R( Slope = temperature change / time change )The tangent line is also shown.
[0028]
  When the manipulated variable MV changes from the lower limit value to the upper limit value as shown in FIG. 5A at the time of temperature rise, the detected temperature shown in FIG. 5B is normal when the heater is not disconnected. The maximum slope R of PV change is always substantially constant.
[0029]
  On the other hand, for example, when at least one of the heaters 3 connected in parallel or the heaters 3 connected in parallel to each other is Δ-connected or star-connected, the amount of generated heat is reduced. As shown in FIG. 5C, the maximum gradient R of the change in the detected temperature PV is approximately ½ or 2/3 of the normal time.
[0030]
  ThereAnd thenThe maximum gradient R at the time of temperature rise until the outlet temperature reaches the target temperature is measured, the maximum gradient R is compared with a predetermined threshold value, and when the measured maximum gradient R becomes smaller than the threshold value, the heater It is determined that the disconnection has occurred.
[0031]
  FIG. 3 is a block diagram of the main parts of the temperature controller 7 and the host computer 8 of FIG. 1, and parts corresponding to those in FIG.
[0032]
  The temperature controller 7 outputs the manipulated variable MV so that the detected temperature PV from the temperature sensor 6 becomes the target temperature SP given from the host computer 8.As temperature controllerA PID controller 9 is provided, and a maximum inclination calculation means 10 that calculates the maximum inclination R based on the detected temperature PV and the manipulated variable MV and gives it to the host computer 8 is provided.
[0033]
  The calculation of the maximum slope R is the same as the conventional auto-tuning (self-tuning) for determining the PID constant, and is calculated by the following equation, for example.
[0034]
  R = ΔPV / {Δt × (MV upper limit value−MV lower limit value)}
  Where Δt is a unit time.
[0035]
  thisExampleAccording to the above, it is possible to detect the disconnection of the heater by using the maximum gradient R obtained in the automatic tuning (self-tuning) for determining the conventional PID constant as it is.
[0036]
  The upper computer 8 stores the maximum inclination in the normal state in which the heater is not disconnected in the storage unit 11, and the upper computer 8 calculates the maximum inclination R from the temperature controller 7 and the maximum inclination in the normal state. In comparison, when the maximum inclination R becomes smaller than a predetermined threshold value, it is determined that the heater is disconnected, for example, a heater disconnection determination is displayed on the display device 12 provided in the control panel of the injection molding machine 1. Means 13 are provided.
[0037]
  FIG. 4 is a diagram illustrating an example of the configuration of the heater disconnection determination unit 13, and the maximum gradient R from the temperature controller 7 is divided by the maximum normal gradient stored in the storage unit 11 and stored in advance. The heater disconnection detection signal is output when the threshold value 14 is compared with the comparator 15 and becomes smaller than the threshold value.
[0038]
  As described above, since the heater disconnection is detected based on the maximum inclination at the time of temperature rise, that is, the heater disconnection is detected by software processing, a plurality of current sensors and a plurality of heater currents are detected as in the above-described conventional example. A measurement circuit or the like is not required, the configuration is simplified, and the cost can be reduced.
[0039]
  AboveReference exampleThen, the maximum slope R when raising the temperature from room temperature to the target temperature was measured to detect the heater disconnection.ExampleFor example, the heater disconnection may be detected based on the maximum gradient R when the target temperature is changed.
[0040]
  5 (a), (b), and (c) show the manipulated variable MV when the target value is changed, the change in the detected temperature PV at the normal time, and the change in the detected temperature PV when the heater is disconnected, respectively. A tangent line with an inclination R is also shown.
[0041]
  In this case, the maximum gradient R is calculated by the following equation, for example.
[0042]
  R = ΔPV / {Δt × (MV upper limit value−MV setting value)}
  Note that the above-mentionedReference examplesOf course, these may be combined.
[0043]
  Also, the aboveReference exampleThen, although an example of 1ch (channel) has been described, as shown in FIG. 6, it is of course applicable to the case of a plurality of channels in the same manner. As shown in FIG. 7, the normal maximum slope and threshold value may be common to each channel.
[0044]
  FIG. 8 shows another heater disconnection judgment means in the case of multiple channels.ExampleFIG.
[0045]
  thisExampleIs a configuration in which when the voltage of the AC power supply 5 decreases and the maximum slope R decreases, it is not erroneously detected that the heater is disconnected.
[0046]
  That is, thisExampleThen, the absolute value average of values obtained by dividing the maximum slope measured by the temperature controller 7 for each channel by the maximum slope at normal time is calculated by the absolute value average calculating means 16, and the calculated absolute value average is calculated. The comparator 15 compares the value obtained by subtracting a predetermined fixed value 17 from the value as a threshold value.
[0047]
  This fixed value is a value obtained by subtracting from the average absolute value at the normal time when there is no voltage fluctuation of the AC power supply 5 and no heater disconnection occurs.Figure of4 and the threshold value of FIG.
[0048]
  thisExampleThen, when the voltage of the AC power supply 5 decreases and the maximum inclination of all the channels ch decreases, and the value obtained by dividing the maximum inclination by the normal maximum inclination decreases, the absolute value average calculating means 16 The absolute value average value is also reduced, and the threshold value given to each comparator 15 is also reduced. As a result, the value obtained by dividing the maximum inclination by the normal maximum inclination does not fall below the threshold value, and the heater is disconnected. Will not be detected.
[0049]
  On the other hand, when the heater of a certain channel is disconnected and the maximum inclination of only that channel is small, the absolute value average value by the absolute value average calculating means 16 is hardly reduced, and therefore the threshold value is hardly reduced. . For this reason, the value obtained by dividing the maximum slope of the channel by the maximum slope at the time of normal falls below the threshold value, and the heater disconnection is detected.
[0050]
  The comparison determination by the heater disconnection determination meansExampleOf course, the heater breakage determination means may be provided on the temperature regulator 7 side so that the heater breakage can be detected by the temperature regulator 7.
[0051]
  (Reference example2)
  FIG.Other reference examplesFIG. 4A is a diagram showing a change in the manipulated variable MV at the normal time, and FIG. 4B is a diagram showing a change in the detected temperature PV at the normal time. FIG. 6C is a diagram showing a change in the manipulated variable MV when the heater is disconnected, and FIG. 10D is a diagram showing a change in the detected temperature PV when the heater is disconnected. is there. In addition, the whole structure of the injection molding machine 1 as a heat processing apparatus is the above-mentioned in FIG.Reference exampleBasically the same as 1.
[0052]
  The steady gain K, which is a value obtained by dividing the temperature increase obtained by subtracting the room temperature from the detected temperature PV shown in FIG. 5B with the manipulated variable MV after settling shown in FIG. In normal times it is always almost constant.
[0053]
  On the other hand, for example, when at least one of the heaters 3 connected in parallel or the heaters 3 connected in parallel to each other is Δ-connected or star-connected is disconnected, this is shown in FIG. Since the manipulated variable MV increases as described above, the steady-state gain is approximately ½ or 2/3 of that in the normal state.
[0054]
  So thisExampleThen, the steady gain K at the time of settling after the temperature rise is measured, the steady gain K is compared with a predetermined threshold value, and when the measured steady gain K becomes smaller than the threshold value, the heater breaks. It is judged that.
[0055]
  Figure 10 shows thisExampleFIG. 7 is a block diagram of the main parts of the temperature controller 7a and the host computer 8a.Reference exampleFIG. 4 is a diagram corresponding to FIG.
[0056]
  thisExampleThe temperature controller 7a includes a PID controller 9 that outputs an operation amount MV so that the detected temperature PV from the temperature sensor 6 becomes a target temperature SP given from the host computer 8a, and the detected temperature PV and the operation amount. A steady gain calculating means 18 is provided which calculates a steady gain K based on MV and gives it to the host computer 8a.
[0057]
  The steady gain K is calculated by the following equation, for example.
[0058]
  K = (PV−room temperature) / (setting MV)
  The calculation of the steady gain K is on condition that the fluctuation of the detected temperature PV is small and the fluctuation of the manipulated variable MV is small. Since the manipulated variable MV may fluctuate even during settling, the signal of the manipulated variable MV is averaged as necessary. Further, PV in the above formula may be replaced with the target temperature SP.
[0059]
  The host computer 8a stores a normal gain when the heater is not disconnected in the storage unit 11a. The host computer 8a uses the steady gain K from the temperature controller 7a and the normal gain when the heater is normal. In comparison, when the steady gain K becomes smaller than a predetermined threshold value, it is determined that the heater is disconnected, and for example, a heater disconnection determination means is displayed on the display device 12 provided in the control panel of the injection molding machine. 13a.
[0060]
  FIG. 11 is a diagram showing the configuration of the heater disconnection determining means 13a, which is stored in advance by dividing the steady gain K from the temperature controller 7a by the normal steady gain stored in the storage unit 11a. When the threshold value 14a is compared with the comparator 15 and becomes smaller than the threshold value, a heater disconnection detection signal is output.
[0061]
  Also, the aboveReference example6, the same applies to the case of a plurality of channels shown in FIG. 6. In the case of a plurality of channels, the heater disconnection determination means, as shown in FIG. The normal steady-state gain and the threshold value 14a may be common to each channel.
[0062]
  In addition, the aboveReference exampleSimilarly to FIG. 8 of FIG. 1, when the voltage of the AC power supply 5 decreases and the steady gain K decreases, it may not be erroneously detected that the heater is disconnected. That is, as shown in FIG. 13, the absolute value average calculating means 16a calculates the absolute value average of the values obtained by dividing the steady gain K measured by the temperature controller 7a for each channel by the normal gain at the normal time. Then, the comparator 15 may compare the value obtained by subtracting the predetermined fixed value 17a as a threshold value.
[0063]
  As shown in FIG. 9 described above, since the settling operation amount increases when the heater is disconnected, the heater disconnection may be detected based on the settling operation amount instead of the steady gain K.
[0064]
  FIG. 14 detects the disconnection of the heater based on the settling operation amount MV0.ExampleFIG. 11 is a block diagram corresponding to FIG. 10.
[0065]
  The temperature controller 7b includes a PID controller 9 that outputs an operation amount MV so that the detected temperature PV from the temperature sensor 6 becomes a target temperature SP given from the host computer 8b, and based on the operation amount MV, A settling operation amount calculation means 19 is provided which calculates the settling operation amount MV0 and gives it to the host computer 8b.
[0066]
  Even during settling, the manipulated variable MV may fluctuate, so the signal of the manipulated variable MV is averaged as necessary.
[0067]
  The host computer 8b stores the settling operation amount in a normal state where no heater disconnection has occurred in the storage unit 11b. The host computer 8b includes the settling operation amount MV0 from the temperature controller 7b and the settling operation in a normal state. When the amount of settling operation exceeds a predetermined threshold and the amount of settling operation becomes large, it is determined that the heater is disconnected, and for example, a heater is displayed on the display device 12 provided on the control panel of the injection molding machine. The disconnection judgment means 13b is provided.
[0068]
  However, since the amount of settling operation at the normal time varies depending on the target temperature SP, the determination of the heater disconnection is performed for the predetermined target temperature SP. Alternatively, for each of the plurality of target temperatures SP, the settling operation amount at the normal time is stored in advance, and when the settling operation amount MV0 corresponding to the target temperature SP is measured, it is determined whether or not the heater is disconnected. May be.
[0069]
  (Reference example3)
  FIG. 15 shows still another embodiment of the present invention.Reference exampleFIG. 4A is a diagram showing an operation amount MV at the time of settling in a normal case, and FIG. 4B is a diagram showing a deviation in a normal case. FIG. 4C is a diagram showing a change in the manipulated variable MV when a heater break occurs, and FIG. 4D is a diagram showing a deviation change when a heater break occurs. In addition, the whole structure of the injection molding machine 1 as a heat processing apparatus is the above-mentioned in FIG.Reference exampleBasically the same as 1.
[0070]
  The deviation (target temperature SP−detected temperature PV) after settling shown in FIG. 5B remains substantially zero, and the manipulated variable MV is also substantially constant as shown in FIG.
[0071]
  On the other hand, for example, when at least one of the heaters 3 in which two are connected in parallel or the heater 3 in which three are connected in a Δ connection or a star connection is disconnected, this is shown in FIG. Thus, the deviation once increases and approaches 0, and finally becomes approximately 0. Or a deviation remains. Further, as shown in FIG. 5C, the manipulated variable MV once increases and then becomes a substantially constant value.
[0072]
  However, deviation also occurs when there is a disturbance or a target value change.
[0073]
  So thisExampleThen, after determining the settling, it is determined that the heater is disconnected when the deviation exceeds a predetermined criterion value under the condition that it can be determined that there is no disturbance and no target value response.
[0074]
  Figure 16 shows thisExampleFIG. 7 is a block diagram of the main parts of the temperature controller 7c and the host computer 8c.Reference exampleFIG. 4 is a diagram corresponding to FIG.
[0075]
  The temperature controller 7c includes a PID controller 9 that outputs an operation amount MV so that the detected temperature PV from the temperature sensor 6 becomes the target temperature SP given from the host computer 8c, and the detected temperature PV and the target temperature SP. Based on the above, a deviation calculating means 20 is provided which calculates a deviation and gives it to the host computer 8c.
[0076]
  The deviation e is calculated by the following equation.
[0077]
  e = SP-PV
  The host computer 8c stores deviation determination reference values for determining the presence or absence of heater disconnection in the storage unit 11c. The host computer 8c is shown in FIG. 17 under the condition that there is no disturbance or target value change. As described above, the deviation from the temperature controller 7c is compared with the determination reference value by the comparator 15, and when the deviation exceeds the determination reference value, it is determined that the heater is disconnected, for example, control of the injection molding machine. A heater disconnection judging means 13c for displaying on the display device 12 arranged on the panel is provided.
[0078]
  FIG. 18 is a flow chart for explaining the operation of the heater disconnection determining means 13c. First, it waits until settling (step n1), determines whether there is a disturbance (step n2), and when there is no disturbance, It is determined whether or not the value has been changed (step n3). When there is no target value change, it is determined whether or not the deviation is greater than or equal to the determination reference value (step n4). Is displayed (step n5), and the process ends.
[0079]
  That is, the heater disconnection determination means 13c of the host computer 8c determines that the heater disconnection has occurred when there is no disturbance, there is no response to the target value, and the current deviation exceeds the determination reference value under the settling condition. It is displayed on the device 12. Here, disturbance refers to the flow of raw material resin to the injection molding machine at the start of injection molding, or the controlled object, such as bringing the injection nozzle into contact with the mold, is deprived of heat and the temperature drops. It is a factor of temperature fluctuation that occurs in a normal state, not a heater disconnection. On the injection molding machine side, that is, the host computer 8c that controls the injection molding machine, it can be known in advance that such a disturbance is applied. Therefore, it can be determined that the temperature fluctuation at this time is normal, not the heater disconnection. Is processed.
[0080]
  In addition to the configuration in which the temperature controller 7d calculates the deviation and gives it to the host computer 8d, as shown in FIG. 19, the temperature controller 7d is provided with a storage unit 21d that stores the deviation criterion value. In addition, a disconnection determination means 22d for calculating a deviation and comparing the determination reference value to determine disconnection is provided, and the determination result is given to the host computer 8d. In the host computer 8d, when the disturbance or the target value is changed, the heater is disconnected. The determination by the determination means 13d is prohibited by an inhibition signal (Inhibit signal), and the final determination is made by the heater disconnection determination means 13d based on the determination result from the temperature controller 7d when there is no disturbance and the target value is not changed. May be performed.
[0081]
  Alternatively, as shown in FIG. 20, when the temperature controller 7e receives from the host computer 8e a prohibition signal (Inhibit signal) that prohibits the determination at the time of disturbance or target value change, the prohibition signal is not given. The disconnection determination means 22e determines the presence or absence of disconnection, and gives the determination result to the host computer 8e. The heater disconnection determination means 13e of the host computer 8e uses the determination result as a final determination to the display device 12 when the heater is disconnected. It is what is displayed.
[0082]
  Also, the aboveReference example6, the same applies to the case of a plurality of channels shown in FIG. 6. In the case of a plurality of channels, as shown in FIG. 21, a criterion for comparison with the deviation of each channel. The value may be common to each channel.
[0083]
  In addition, the aboveReference exampleSimilarly to FIG. 8 of FIG. 1, when the voltage of the AC power supply 5 decreases, it may not be erroneously detected that the heater is disconnected. That is, as shown in FIG. 22, an average value of deviations for each channel is calculated by the average calculation means 23, and a value obtained by adding a predetermined fixed value 24 is compared by the comparator 15 as a determination reference value. You may make it do.
[0084]
  Each of the aboveReference exampleThen, in the event of disturbance or target value change, in order to prohibit the determination of the heater disconnection, the heater disconnection determination means 13c to 13e of the host computer determine whether or not there is a final heater disconnection.Embodiment of the present inventionAs shown in FIG. 23, it is finally determined whether or not the heater is disconnected on the temperature controller side.As disconnection detection meansA heater disconnection determination means 25 may be provided.
[0085]
  In this case, in order to prevent normal phenomena such as disturbances and target value changes on the temperature controller side from being mistakenly detected as heater disconnection, characteristic fluctuation waveforms due to normal phenomena other than heater disconnection, Phenomenon detection means other than heater disconnection( Disturbance detection means )26 is provided for detection, and a determination prohibition signal is output to each comparator 15 to prohibit the determination of the presence or absence of heater disconnection.
[0086]
  The configuration of the phenomenon detection means 26 other than the heater disconnection will be described. As an example of a fluctuation waveform of a characteristic deviation due to a normal phenomenon other than the heater disconnection, there is a temperature drop due to the flow of the resin when the raw material resin is first fed to the injection molding machine at the start of injection molding.
[0087]
  FIG. 24A shows a deviation due to the flow of the resin indicated by the arrows at the root A point, the intermediate B point, and the tip C point in the injection cylinder 2 of the injection molding machine shown in FIG. It shows the change of.
[0088]
  As shown in FIG. 24, when the resin starts to flow, the resin moves from the base of the injection cylinder 2 toward the tip, so that it is understood that the amount of heat taken away at the base is large and the temperature drop is large. Then, heat is carried by the movement of the resin, and the amount of heat taken away becomes smaller and the amount of temperature decrease becomes smaller toward the tip.
[0089]
  This phenomenon can be detected, for example, by comparing the temperature gradient (temperature difference) along the longitudinal direction of the injection cylinder 2. That is, even if the deviation of the ch on the most root side of the injection cylinder 2 is large, not only this ch but also other ch are small in size, but if there is a similar change, It is judged that the flow of the resin, and the judgment of the heater disconnection is prohibited.
[0090]
  For example, as shown in FIG. 25, the difference between the deviation at point B and the deviation at point A (B-A) and the difference between the deviation at point C and the deviation point at B (C-B) When the comparison is made by the comparator 27 and they are in a certain ratio relationship, a judgment prohibition signal for prohibiting judgment of the heater disconnection is output because it is a variation in deviation due to the flow of the resin.
[0091]
  Furthermore, the temperature drop due to the contact between the injection nozzle and the mold also causes a specific temperature change, and it is possible to output the determination prohibition signal as a phenomenon other than the heater disconnection.
[0092]
  (Reference example4)
  FIG. 26 shows still another embodiment of the present invention.Reference exampleFIG. 4A is a diagram showing an operation amount MV at the time of settling in a normal case, and FIG. 4B is a diagram showing a deviation in a normal case. FIG. 4C is a diagram showing a change in the manipulated variable MV when a heater break occurs, and FIG. 4D is a diagram showing a deviation change when a heater break occurs. In addition, the whole structure of the injection molding machine 1 as a heat processing apparatus is the above-mentioned in FIG.Reference exampleBasically the same as 1.
[0093]
  As shown in FIG. 5A, when the parallel heater operates normally and the control is stabilized, the operation amount MV remains substantially constant.
[0094]
  On the other hand, for example, when at least one of the heaters 3 in which two are connected in parallel or the heater 3 in which three are connected in a Δ connection or a star connection is disconnected, this is shown in FIG. Thus, the deviation once increases and approaches 0, and finally becomes approximately 0. Or a deviation remains. Further, as shown in FIG. 10C, the manipulated variable MV once increases and then reaches a substantially constant settling manipulated variable.
[0095]
  So thisExampleThen, the heater disconnection is detected based on the operation amount MV after determining the settling.
[0096]
  If the manipulated variable fluctuates, accurate detection is possible by averaging and updating. Alternatively, the fluctuation may be detected by a low-pass filter, the gradient of a sudden change may be detected by a differential filter, and if the gradient is more than a certain level, it may be determined that the heater is disconnected.
[0097]
  However, a sudden change in the operation amount occurs both during disturbance and during target response. In order to distinguish them from these, if it is determined that there is no disturbance and no target value response after determining the settling, if the change in the manipulated variable exceeds the criterion value, it is determined that the heater is disconnected, and the heater is disconnected. It detects.
[0098]
  Figure 27 shows thisExampleFIG. 7 is a block diagram of the main parts of the temperature controller 7f and the host computer 8f.Reference exampleFIG. 4 is a diagram corresponding to FIG.
[0099]
  The temperature controller 7f includes a PID controller 9 that outputs an operation amount MV so that the detected temperature PV from the temperature sensor 6 becomes the target temperature SP given from the host computer 8f, and the operation from the PID controller 9 As described above, there is provided an operation amount change measuring / processing means 28 that processes the amount MV with a low-pass filter or the like to measure the operation amount change ΔMV and gives it to the host computer 8f.
[0100]
  In the host computer 8f, a determination reference value of the change amount ΔMV of the operation amount for determining the presence or absence of the heater disconnection is stored in the storage unit 11f, and the host computer 8f is in a condition in which there is no disturbance or target value change. 28, the change amount ΔMV of the manipulated variable from the temperature controller 7f is compared with the determination reference value by the comparator 15, and when the change amount ΔMV of the manipulated variable exceeds the determination reference value, For example, a heater disconnection determining means 13f is provided for displaying on the display device 12 arranged on the control panel of the injection molding machine.
[0101]
  FIG. 29 is a flowchart for explaining the operation of the heater disconnection determining means. First, the process waits until settling (step n1), determines whether there is a disturbance (step n2), and when there is no disturbance, the target value It is determined whether or not a change has been made (step n3), and when there is no change in the target value, it is determined whether or not the operation amount change ΔMV is equal to or greater than a determination reference value (step n4). In some cases, it is determined that the heater is disconnected (step n5), and the process ends.
[0102]
  In other words, the heater disconnection determination means 13f of the host computer 8f determines that a heater disconnection has occurred when there is no disturbance, there is no response to the target value, and the change ΔMV in the manipulated variable exceeds the determination reference value under the set conditions. Then, it is displayed on the display device 12. Here, disturbance refers to the temperature of the controlled object such as first flowing the raw material resin through the injection molding machine at the start of injection molding as described above, or bringing the injection nozzle into contact with the mold. It is a factor of temperature fluctuation that occurs in a normal state, not a heater disconnection such as lowering. Since the host computer 8f that controls the injection molding machine knows in advance that such a disturbance is applied, the temperature fluctuation at this time is processed so that it can be determined that it is normal rather than the heater disconnection.
[0103]
  In addition to the configuration in which the temperature controller 7f calculates the change amount ΔMV of the manipulated variable and gives it to the host computer 8f, the temperature controller 7g determines the change amount ΔMV of the manipulated variable as shown in FIG. A storage unit 29g for storing a reference value is provided, and a disconnection determination means 30g for determining a disconnection is provided by comparing a change ΔMV in the manipulated variable measured and measured with a determination reference value, and the determination result is given to the host computer 8g. In the host computer 8g, when the disturbance or the target value is changed, the judgment by the heater disconnection judging means 13g is prohibited by a prohibition signal (Inhibit signal), and the judgment from the temperature controller 7g when there is no disturbance and the target value is not changed. Based on the result, the heater disconnection determination means 13g may make a final determination.
[0104]
  Alternatively, as shown in FIG. 31, when the temperature controller 7h receives from the host computer 8h a prohibition signal (Inhibit signal) that prohibits the determination at the time of disturbance or target value change, the prohibition signal is not given. The disconnection determination means 30h determines the presence or absence of disconnection, and gives the determination result to the host computer 8h. The heater disconnection determination means 13h of the host computer 8h uses the determination result as a final determination to the display device 12 when the heater is disconnected. It is what is displayed.
[0105]
  Also, the aboveReference exampleAs in the case of 1, the same applies to the case of a plurality of channels shown in FIG. 6. In the case of a plurality of channels, as shown in FIG. The determination reference value to be compared may be common to each channel.
[0106]
  In addition, the aboveReference exampleSimilarly to FIG. 8 of FIG. 1, when the voltage of the AC power supply 5 decreases, it may not be erroneously detected that the heater is disconnected. That is, as shown in FIG. 33, an average value of deviations for each channel is calculated by the average calculation means 31, and a value obtained by adding a predetermined fixed value 32 is compared by the comparator 15 as a determination reference value. You may make it do.
[0107]
  In addition, the aboveReference exampleAs in FIG. 23 of FIG. 3, a characteristic fluctuation waveform due to a normal phenomenon other than the heater disconnection is detected by providing a phenomenon detection means other than the heater disconnection to prohibit the determination of the presence or absence of the heater disconnection, thereby adjusting the temperature. It may be possible to finally determine whether or not the heater is disconnected only by the heater.
[0108]
  (Form of implementationstate)
  FIG. 34 shows the present invention.The fruitIt is a wave form chart for explaining an embodiment, the figure (a) is a figure showing detection temperature PV in the case of normal, and the figure (b) shows the amount of operation MV in the case of normal. FIG. 8C is a diagram showing a change in the detected temperature PV when the heater is disconnected, and FIG. 9D is a diagram showing a change in the operation amount MV when the heater is disconnected. It is.
[0109]
  The overall configuration of the injection molding machine 1 as a heat treatment apparatus is basically the same as that of the above-described reference example 1 shown in FIG. 1, but in this embodiment, three heaters are Δ-connected or star-connected. This will be applied to the case where one of the three-phase heaters is disconnected.
[0110]
  As shown in FIGS. 4A and 4B, when the three-phase heater operates normally and the control is settling, the detected temperature PV substantially coincides with the target temperature SP, and the setting operation is performed. The first settling operation amount MV1, which is the amount, remains substantially constant.
[0111]
  On the other hand, as shown in FIGS. 3C and 3D, when the one-phase heater of the three-phase heater is disconnected and the output of the heater is lowered, the detected temperature PV becomes the same even if the operation amount is the same. Start to decline. For this reason, the operation amount increases so as to suppress the temperature drop, and after settling is finished, the settling is performed again. The disconnection of the heater is detected by utilizing the fact that the second settling operation amount MV2 when settling again becomes approximately 3/2 times the first settling operation amount MV1.
[0112]
  For example, in a state where three heaters of three phases are heated and set at a total of 300 W at an operation amount of 10%, assuming that one heater is disconnected and the total heat generation amount is 200 W, a total of 300 W In order to secure the heat generation amount and settling again, the operation amount is 1.5 times 15%, and the heat generation amounts of the two heaters that are not disconnected become 150 W, respectively.
[0113]
  Therefore, in this embodiment, the second settling operation amount MV2 that is the operation amount when the settling is lost and set again is the first settling operation amount MV1 that is the operation amount at the settling time before the settling is released. It is determined that the heater is disconnected by detecting that it has increased by about 1.5 times.
[0114]
  Further, in consideration of the variation in the calorific value of the three heaters and the difference in the mounting position of the temperature sensor and each heater, a predetermined range centered on the 1.5 times, for example, 1.5 ± 0.2. It is determined that the heater has been disconnected by detecting the double.
[0115]
  FIG. 35 is a block diagram of the main parts of the temperature controller 7i and the host computer 8i of this embodiment.Reference exampleFIG. 4 is a diagram corresponding to FIG.
[0116]
  The temperature controller 7i includes a PID controller 9 that outputs an operation amount MV so that the detected temperature PV from the temperature sensor 6 becomes the target temperature SP given from the host computer 8i, and the operation from the PID controller 9 Based on the amount MV, the heater disconnection detecting means 40 for detecting the disconnection of the heater as described above is provided, and when the disconnection of the heater is detected, a detection signal is given to the host computer 8i, whereby For example, the computer 8i displays a disconnection on the display device 12 disposed on the control panel of the injection molding machine.
[0117]
  FIG. 36 is a flowchart for explaining the operation of the heater disconnection detecting means 40. First, it is periodically determined whether or not the settling is performed (step n1). This determination is, for example, determined as settling when the detected temperature PV is within a certain range over a certain period. When settling, the settling operation amount as the first settling operation amount is measured and updated at regular intervals (step n2), and it is determined whether or not the settling is out, that is, whether or not the certain range is exceeded. (Step n3) When the settling is lost, the operation amount at the time of the last settling is stored as the first settling operation amount (Step n4).
[0118]
  Next, it is periodically determined whether or not the settling is performed again (step n5). When the settling is performed again, the settling operation amount as the second settling operation amount is measured (step n6), and the second settling operation amount is measured. Is about 1.5 times the first settling operation amount, for example, about 1.3 times to 1.7 times (step n7), and about 1.5 times. If not, return to step n1 because the heater is not disconnected, and if it is about 1.5 times, output a detection signal to the upper computer 8i (step n8), for example, assuming that one phase of the three-phase heater is disconnected (step n8). In response to the detection cancellation command from the host computer 8i, the process returns to step n1 (step n9).
[0119]
  Here, although 1 ch has been described, the present invention can be similarly applied to the case of a plurality of channels shown in FIG. 6. In the case of a plurality of channels, there is a very high probability that heater breaks will occur simultaneously in a plurality of channels. Taking advantage of the small size, only the settling operation amount of one channel of multiple channels is about 1.5 times, and it is determined that there is almost no change in the settling operation amount of other channels and it is determined that the heater is disconnected. May be.
[0120]
  In this way, for example, a normal disturbance in which the raw material resin is first supplied to the injection molding machine at the start-up of the injection molding, that is, a disturbance in which the set operation amount of all the channels fluctuates, There is no false detection.
[0121]
  FIG. 37 is a flowchart of heater disconnection detection in the case of such a plurality of channels, and portions corresponding to the above-described FIG. 36 are given corresponding step numbers.
[0122]
  In step n7, when it is determined that the second settling operation amount is about 1.5 times the first settling operation amount, in other channels, the second settling operation amount is set to the first settling operation amount. It is judged whether or not the amount is about 1.5 times (step n7 '), and when other channels are also about 1.5 times, when the injection molding is started up, the raw material resin is supplied to the injection molding machine. And return to step n1 as normal disturbances such as
In step n7 ', when the other channels are not about 1.5 times, a detection signal is output to the host computer 8i on the assumption that one phase of the three-phase heater of one channel is disconnected (step n8). .
[0123]
  As in the above-described fourth embodiment, when there is a fluctuation in the operation amount, it is preferable to use a low-pass filter or the like.
[0124]
  In this embodiment, it is detected that the second settling operation amount has become a predetermined range centered on 1.5 times the first settling operation amount, for example, 1.5 ± 0.2 times. Although it is determined that the heater is disconnected, as another embodiment of the present invention, the second settling operation amount is a predetermined range centered at 1.0 times the first settling operation amount, for example, 1.0 ± 0. .2 out of range or the second settling operation amount is a predetermined value smaller than 1.5 times the first settling operation amount, for example, 1.3 times or more May be detected to determine that the heater is disconnected.
[0125]
  In particular, one heater of a three-phase heater is detected by detecting that the second settling operation amount is equal to or greater than a predetermined value smaller than 1.5 times the first settling operation amount and determining that the heater is disconnected. The disconnection can be detected not only when the heater is disconnected but also when the two heaters are disconnected (in this case, the second settling operation amount is approximately 3.0 times the first settling operation amount). Become.
[0126]
  According to this embodiment, the disconnection of the heater can be detected only on the temperature controller 7i side.
[0127]
  In this embodiment, the present invention is applied to a three-phase heater, but is not limited to a three-phase heater, and n (n is a natural number of 2 or more) Heaters are connected in parallel and energized and controlled in the same manner. In this case, the second settling operation amount is n / (n-1) of the first settling operation amount. The disconnection of the heater can be detected by utilizing the fact that it is about double.
[0128]
  (Other embodiments)
  In the above-described embodiment, one channel is configured by a plurality of heaters, but it is needless to say that disconnection can be similarly detected even when the channel is configured by one heater.
[0129]
  Other embodiments of the present invention may be appropriately combined. For example, when a heater break is detected based on any of the maximum inclination, steady gain, operation amount, or deviation, the heater break may be used.
[0130]
  In the above-described embodiment, the heat treatment apparatus has been described as applied to an injection molding machine. However, the present invention is not limited to an injection molding machine, but is an extrusion molding machine, a compression molding machine, a thermal oxidation apparatus used in a semiconductor process, a sheet. The present invention can also be applied to other apparatuses that perform heat treatment using a heater such as a leaf type CVD apparatus.
[0131]
【The invention's effect】
  As described above, according to the present invention,Maximum slope of the detected temperature waveform until the detected temperature of the control target reaches the target temperature ( Inclination = Change in detected temperature / Change in time ) , Based on at least one of the steady gain after settling, the manipulated variable after settling, and the deviation after settling,Since the disconnection of the heater is detected, a conventional current sensor, a heater current measuring circuit, or the like is not required, and the disconnection of the heater can be detected with a simple configuration and at a low cost.
[Brief description of the drawings]
[Figure 1]Reference heat treatment systemFIG.
[Figure 2]Disconnection detection in Fig. 1It is a wave form diagram for demonstrating.
3 is a block diagram of the main parts of the temperature controller and the host computer of FIG. 1. FIG.
4 is a block diagram of the host computer of FIG. 3. FIG.
[Figure 5]Other reference examplesIt is a wave form diagram for demonstrating.
FIG. 6 is a schematic configuration diagram in the case of multiple channels.
FIG. 7 is a block diagram of a host computer in the case of multiple channels.
[Fig. 8]Other reference examplesFIG. 8 is a block diagram corresponding to FIG. 7.
FIG. 9Other reference examplesIt is a wave form diagram for demonstrating.
FIG. 10Reference exampleIt is a block diagram of the principal part of this temperature controller and a high-order computer.
11 is a block diagram of the host computer of FIG.
FIG. 12 is a block diagram of a host computer in the case of multiple channels.
FIG. 13Other reference examplesFIG. 9 is a block diagram corresponding to FIG. 8.
FIG. 14Other reference examplesFIG. 11 is a block diagram corresponding to FIG. 10.
FIG. 15Still other reference examplesIt is a wave form diagram for demonstrating.
FIG. 16Reference exampleIt is a block diagram of the principal part of this temperature controller and a high-order computer.
FIG. 17 is a block diagram of the upper computer in FIG. 16;
FIG. 18 is a flowchart for explaining the operation;
FIG. 19Other reference examplesFIG. 17 is a block diagram corresponding to FIG. 16.
FIG. 20Still other reference examplesFIG. 17 is a block diagram corresponding to FIG. 16.
FIG. 21 is a block diagram of a host computer in the case of multiple channels.
FIG. 22Other reference examplesFIG. 9 is a block diagram corresponding to FIG. 8.
FIG. 23 shows the present invention.The fruitIt is a block diagram of the heater disconnection judgment means provided in the temperature controller which concerns on embodiment.
24 is a diagram for explaining the detection principle of the phenomenon detection means of FIG. 23. FIG.
25 is a block diagram showing a configuration of the phenomenon detection unit of FIG. 23. FIG.
FIG. 26Reference exampleIt is a wave form diagram for demonstrating.
FIG. 27TemperatureIt is a block diagram of the principal part of a degree adjuster and a high-order computer.
28 is a block diagram of the host computer of FIG.
FIG. 29 is a flowchart for explaining the operation;
FIG. 30Other reference examplesFIG. 28 is a block diagram corresponding to FIG.
FIG. 31Still other reference examplesFIG. 28 is a block diagram corresponding to FIG.
FIG. 32 is a block diagram of a host computer in the case of multiple channels.
FIG. 33Other reference examplesFIG. 9 is a block diagram corresponding to FIG. 8.
FIG. 34The fruitIt is a wave form diagram for demonstrating embodiment.
FIG. 34 is a block diagram of the main parts of the temperature controller and the host computer according to the embodiment in FIG.
FIG. 36 is a flowchart for explaining the operation;
FIG. 37 is a flowchart for explaining the operation;
[Explanation of symbols]
  1 Injection molding machine
  2 Injection cylinder
  3 Heater
  5 AC power supply
  6 Temperature sensor
  7, 7a-7h Temperature controller
  8,8a-8h Host computer
  9 PID controller
  10 Maximum slope calculation means
  13, 13a-13h Heater disconnection judgment means
  18 Steady gain calculation means
  20 Deviation calculation means
  28 Operation amount change measurement processing means

Claims (5)

A temperature controller that outputs an operation amount so that a deviation between the detected temperature of the control target and the target temperature is eliminated, and a switch that turns on and off the heater that heats the control target is controlled based on the operation amount. In the temperature regulator for controlling the temperature of the controlled object by controlling the energization of the heater,
Maximum slope of the detected temperature waveform until the detected temperature of the control target reaches the target temperature ( Slope = Change in detected temperature / Change in time ) A breakage detecting means for detecting breakage of the heater based on at least one of a steady gain after settling, the manipulated variable after settling and the deviation after settling,
The disconnection detection means includes a disturbance detection means for detecting a normal disturbance corresponding to the input of the workpiece to be heat-treated by the control object to the control object, and during normal disturbance, detection of disconnection of the heater is prohibited. And
The disturbance detection means is provided with detection outputs of a plurality of temperature detection means for detecting the temperature of the control object at at least three different locations along the movement direction of the object to be processed in the control object, The disturbance detector detects the normal disturbance based on a temperature difference between detected temperatures detected at the different locations. A temperature controller that outputs an operation amount so that a deviation between the detected temperature of the control target and the target temperature is eliminated, and a switch that turns on and off the heater that heats the control target is controlled based on the operation amount. To control the temperature of the object to be controlled by controlling energization of the heater, and n ( n is a natural number of 2 or more ) In the temperature controller for controlling the energization for each channel in which one channel is configured by the heater,
A disconnection detecting means for detecting disconnection of the heater based on a first settling operation amount that is an operation amount at the time of settling and a second settling operation amount that is an operation amount when the settling is lost and set again. Prepared,
The disconnection detecting means detects the disconnection of the heater on the condition that the second settling operation amount is about n / (n-1) times the first settling operation amount. air conditioner. The disconnection detecting means detects a disconnection of the heater on the condition that the second settling operation amount is in a predetermined range centering on n / (n-1) times the first settling operation amount. 3. The temperature controller according to claim 2, wherein the predetermined range is determined in advance so as to take into account variations in the amount of heat generated by the heater and not to include the first settling operation amount. A temperature controller that outputs an operation amount so that a deviation between the detected temperature of the control target and the target temperature is eliminated, and a switch that turns on and off the heater that heats the control target is controlled based on the operation amount. To control the temperature of the object to be controlled by controlling energization of the heater, and n ( n is a natural number of 2 or more ) In the temperature adjuster in which one channel is constituted by the heater and the energization is controlled for each channel,
A disconnection detecting means for detecting disconnection of the heater based on a first settling operation amount that is an operation amount at the time of settling and a second settling operation amount that is an operation amount when the settling is lost and set again. Prepared,
The disconnection detection unit detects disconnection of the heater on condition that the second settling operation amount is equal to or greater than a predetermined value smaller than n / (n-1) times the first settling operation amount. Is,
The temperature controller according to claim 1, wherein the predetermined value is determined in advance so as not to include the first settling operation amount in a range equal to or greater than the predetermined value in consideration of variation in the heat generation amount of the heater. A temperature controller that outputs an operation amount so that a deviation between the detected temperature of the control target and the target temperature is eliminated, and a switch that turns on and off the heater that heats the control target is controlled based on the operation amount. A heat treatment apparatus comprising: a temperature controller that controls energization of the heater to control the temperature of the control target; and a disconnection detection device that detects disconnection of the heater,
The temperature controller is configured to detect a detected temperature waveform until the detected temperature of the control target reaches a target temperature. Maximum slope ( Slope = Change in detected temperature / Change in time ) , At least one of a steady gain after settling, the manipulated variable after settling, and the deviation after settling can be output to the disconnection detection device,
The disconnection detection device detects disconnection of the heater based on the at least one output from the temperature controller, and the control target of an object to be heat-treated by the control target Including disturbance detection means for detecting normal disturbance corresponding to charging to the heater, and during normal disturbance, detection of disconnection of the heater is prohibited,
The disturbance detection means is provided with detection outputs of a plurality of temperature detection means for detecting the temperature of the control object at at least three different locations along the movement direction of the object to be processed in the control object, The disturbance detecting means detects the normal disturbance based on a temperature difference between detected temperatures detected at the different locations.

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