JP2019070584A - Electronic controller - Google Patents

Abstract

To provide an electronic controller with which it is possible to guarantee fast sampling intervals without having to separately install a monitoring unit for monitoring sampling intervals on the basis of communication with the outside.SOLUTION: A CPU 11 of a microcomputer 7 outputs a diagnostic pulse signal based on a one shot trigger in S23 causing an analog signal to be fed into the input unit of an A/D converter 14, and performs sampling diagnosis in S27-S30 for determining whether or not a sample value obtained each time the A/D converter 14 samples the analog signal multiple times separately falls within an expectation range between the expected upper-limit Max and expected lower-limit Min that are prescribed for each sampling performed, and determines whether or not the sampling interval is abnormal on the basis of the result of this sampling diagnosis.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electronic control device.

  Conventionally, the A / D conversion device has a method of sampling an analog signal at a fixed cycle in the shortest task in the system and a method of sampling an analog signal at an interrupt occurrence timing, and this method is used properly depending on the application. ing. For example, when higher speed sampling is required, A / D conversion processing may be sampled using a timer interrupt at a cycle shorter than the shortest task.

  In particular, when AD conversion data is used for control processing to which the functional safety standard ISO 26262 of the automotive field is applied, it may be necessary to ensure that the sampling interval of the AD conversion data is appropriate. There is generally provided a technique for ensuring the sampling interval by setting the communication interval between the monitoring unit and the microcomputer provided in the same as the sampling interval, and setting the communication interval as a monitoring target.

  That is, when the A / D conversion device is sampling the A / D converted data of the sensor in a task of 1 ms, for example, the monitoring IC communicates with the external monitoring IC in the same 1 ms task processing, and this communication cycle Monitor and guarantee sampling intervals. In such a technique, when high-speed sampling intervals are required, high-speed communication imposes a burden on monitoring processing, and high-speed sampling intervals can not be guaranteed.

  In addition, the technique of patent document 1 is mentioned as a document relevant to this application. The technique described in Patent Document 1 is a technique for detecting a failure of an external capacitor from the time constant of a CR circuit using sampling results.

JP, 2015-175676, A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an electronic control device capable of guaranteeing a high-speed sampling interval without separately providing a monitoring unit for monitoring the sampling interval based on external communication. It is to provide.

  According to the first aspect of the present invention, the diagnostic pulse signal output unit outputs the diagnostic pulse signal during the period when the normal operation period of the A / D converter is deviated. When an analog signal is input, the abnormality determination unit determines that the sampling value obtained each time the A / D converter samples the diagnostic pulse signal in a plurality of times is predetermined upper limit and expected value determined for each sampling It is determined whether or not it is within the expected range between the lower limit, and whether or not the sampling interval is abnormal according to the determination result.

  For example, if the sampling interval deviates significantly from the standard value, the sampling value obtained each time sampling does not fall within the predetermined expected range, and as a result, it can be determined that the sampling interval is abnormal. Conversely, when the sampling interval is within the allowable range from the standard value, the sampling value falls within a predetermined expected range, and as a result, it can be determined that the sampling interval is normal. As a result, it is possible to guarantee a high-speed sampling interval without separately providing a monitoring unit for monitoring the sampling interval by performing external communication as described in the background art.

Electrical configuration block diagram of the electronic control unit according to the first embodiment Flow chart showing the flow of abnormality detection processing Example of setting sampling diagnosis count and normal judgment count threshold according to environmental temperature and sampling cycle Flow chart showing the flow of sampling diagnostic processing Example of setting expected upper limit and expected lower limit for each sampling Example of sampling acquisition value and tolerance Flow chart showing the flow of abnormality detection processing according to the second embodiment Example of setting the number of sampling diagnoses and the number of anomaly judgment thresholds according to the environmental temperature and the sampling cycle Flow chart showing the flow of abnormality detection processing according to the third embodiment

  Hereinafter, several embodiments of the electronic control device of the present invention will be described with reference to the drawings. In each embodiment described below, the same or similar reference numerals are given to components performing the same or similar operations. In the second and subsequent embodiments, the description of the same or similar configuration and the same or similar operation as described in the first embodiment will be omitted as necessary.

First Embodiment
1 to 6 show an explanatory view of the first embodiment. FIG. 1 shows an electrical configuration block diagram for explaining the present embodiment. A sensor device 2 is connected to an electronic control unit (hereinafter referred to as an ECU) 1. The sensor device 2 is constituted by a temperature sensor in which a fixed resistor 4 and a thermistor 5 are connected in series to a sensor power supply 3. The temperature of the temperature measurement object is measured by installing the thermistor 5 in the vicinity of the temperature measurement object. Do.
The node N1 between the fixed resistor 4 and the thermistor 5 is input to the ECU 1, whereby temperature information is input to the ECU 1. The node N1 is connected to the analog input circuit 6 of the ECU 1, and the output of the analog input circuit 6 is connected to the input port In1 of the microcomputer 7.
The analog input circuit 6 includes an input capacitor Ci and a low pass filter 8. The input capacitor Ci is provided for surge protection that protects the input of the ECU 1 from static electricity. The low pass filter 8 is configured by low pass connecting a resistor 9 and a capacitor 10 connected in series to the node N1, and outputs a signal processed by the low pass filter 8 to an input port In1 of the microcomputer 7.

The microcomputer 7 includes a CPU 11, output timers 12 and 13, an A / D converter 14, and a memory 15 as a non-transitional tangible recording medium. The input port In1 is connected to the A / D converter 14 inside the microcomputer 7. The CPU 11 realizes functions as the diagnostic pulse output control unit 16 and the A / D sampling determination unit 17 according to the program stored in the memory 15. The diagnostic pulse output control unit 16 is a function for outputting a diagnostic pulse signal for diagnosing a sampling trigger from the output port IO1 or IO2 using the output timer 12 or 13.
The CPU 11 includes an internal timer (not shown), and has a function as a sampling trigger generation unit 18 for generating a sampling trigger of the A / D converter 14 by the internal timer. The CPU 11 also has a function as an A / D sampling determination unit 17. The A / D sampling determination unit 17 refers to the result of A / D conversion of the analog signal by the A / D converter 14 to determine whether or not it falls within a predetermined expected range (see later). This block is a block that implements a function as an abnormality determination unit that determines whether the trigger sampling interval of the trigger generation unit 18 is abnormal.

  The A / D converter 14 is provided with a sampling capacitor 14a at the input section, and is configured to perform A / D conversion processing of the accumulated voltage Vc of the capacitor 14a. The A / D converter 14 receives a sampling trigger generated for each fixed period by the sampling trigger generation unit 18 of the CPU 11, and performs sampling processing on an analog signal input to the port In1 at this trigger reception timing. The conversion processing is performed, and the A / D conversion processing result is output to the CPU 11.

Further, the microcomputer 7 includes a plurality of ports IO1 and IO2, and these ports IO1 and IO2 are connected to the input port In1 through the resistors 19 and 20, that is, to the output node N2 of the low pass filter 8. The CPU 11 realizes a function as the diagnostic pulse output control unit 16 according to the program stored in the memory 15. The diagnostic pulse output control unit 16 can output a one-shot trigger as diagnostic pulse signals from the ports IO1 and IO2 through the timers 12 and 13, respectively. Therefore, the diagnostic pulse output control unit 16 and the timers 12 and 13 realize the function as the diagnostic pulse signal output unit 22.
The ports IO1 and IO2 are ports through which the microcomputer 7 can switch input / output from inside. Further, these resistors 19 and 20 are resistors for adjusting time constants. Thus, a CR low pass filter circuit 21 composed of the resistor 19 or 20 and the capacitor 10 is formed between the output node of the ports IO1 and IO2 and the input node of the A / D converter 14.

The operation and operation of the above configuration will be described.
<Error detection process>
FIG. 2 is a flowchart showing an abnormality detection process of the sampling interval. In this abnormality detection processing, as shown in S1 to S10 of FIG. 2, the sampling diagnosis processing of whether or not the sampling value falls within the allowable range is repeated for the number of sampling diagnosis times, and the normal return value among the repetition numbers Whether or not the sampling interval is normal is determined based on whether or not the number of times the normal sampling diagnosis result has returned exceeds the normal determination number threshold. The sampling diagnosis number indicates the number of times the sampling diagnosis process is performed. The normal determination number threshold value indicates a threshold value of the number of normal determinations in which the sampling diagnosis number is determined not to be abnormal.
The sampling diagnosis number and the normality determination number threshold are values set according to the sampling period and the environmental temperature, and the CPU 11 sets the sampling diagnosis number and the normality determination number threshold in S1 of FIG. FIG. 3 shows an example of these setting values. As shown in FIG. 3, the memory 15 of the microcomputer 7 stores, as a table, the number of times of sampling diagnosis and the number of normal judgments according to the sampling cycle and the environmental temperature. Here, the sampling period is shown in the horizontal direction, and the environmental temperature is shown in the vertical direction, and an example of the number of sampling diagnosis times and the number of normal judgment number thresholds according to this combination is shown.

  As shown in FIG. 3, the threshold value for determining the number of normal diagnoses with respect to the number of sampling diagnoses may exceed 1/2, for example, when the number of sample diagnoses is 3, the threshold for the number of normal diagnoses may be 2. It is still more desirable to set the threshold number of normal judgments to 1/2 or less. In this embodiment, two ports of IO1 and IO2 are provided as diagnostic ports, but when abnormality occurs in diagnostic processing by these one-side ports, the other normal port is used. This is because the diagnostic process can be continued under the definite condition that the hardware is normal.

  In addition, the characteristic variation of the CR circuit from the ports IO1 and IO2 to the input port In1 becomes larger as the environmental temperature becomes higher, so the sampling diagnosis frequency is increased and the detection accuracy is raised as the temperature is higher. Is desirable. Further, as the sampling cycle at the time of diagnosis is larger, the deviation of the detection value according to the tolerance of the element value is also larger, so the accuracy is preferably made relatively low, and it is better to make the normal judgment number threshold smaller. By setting each value in this manner, the CPU 11 can diagnose whether the sampling process is appropriate or not within the range where false detection is not made.

  After the processing of S1 in FIG. 2, the CPU 11 initializes a variable i for repetitive processing to 0 in S2. Then, the CPU 11 repeats the processing of S4 to S7 until the variable i reaches the number of sampling diagnoses. The CPU 11 makes a sampling diagnosis in S4, increments the variable i in S5, determines whether the return value of the sampling diagnosis processing is normal in S6, determines YES in S6 if normal and determines a normal counter in S7. To increment Conversely, if the return value of the sampling diagnosis process is abnormal at S6, the CPU 11 determines that the result of S6 is NO, returns the process to S3, and repeats the diagnosis process.

  When the variable i reaches the sampling diagnosis number, the CPU 11 completes the repetitive processing and determines NO in S3 and compares the normal counter with the normal determination number threshold in S8. At this time, if the normal counter exceeds the normal determination frequency threshold, the determination in S8 is NO, and the sampling interval is determined as normal in S9, and if it is less than the normal determination frequency threshold, the determination is YES in S8 and the sampling interval is Determine that it is abnormal.

<Sampling diagnostic processing>
FIG. 4 is a flowchart showing the sampling diagnosis in S4 of FIG. 2 in detail. As shown in FIG. 4, after setting the initial value of the return value as normal in S21, the CPU 11 changes either port IO1 or IO2 (for example, IO1) to output setting in S22, and then S23. The diagnostic output is started on the port IO1 at step S24, and the sampling for the diagnosis is started at step S24.

  The CPU 11 initializes the variable j for repetition to 0 in S25, compares the variable j with the predetermined number of samples in S26, and repeats the processing of S27 to S30 until the number of samples or more can be secured. When the variable j is less than the number of samples, it is determined whether the diagnostic sampling value is less than the expected value lower limit Min at S27, and whether or not the expected value upper limit Max is exceeded at S28.

  FIG. 5 shows the parameter setting method of the sampling expected value upper limit Max and the expected value lower limit Min. In FIG. 5, “sample 1”, “sample 2”, “sample 3”... Indicate sampling timings after a predetermined time interval from the timing when the diagnostic pulse signal is input. In the table, the expected value upper limit Max and the expected value lower limit Min of the sampling shown in FIG. 5 are stored as a table. As shown in FIG. 5, the CPU 11 refers to a table in the memory 15 in which the sample timing in the horizontal direction, the expected value upper limit Max, and the expected value lower limit Min of each diagnostic input are set in the vertical direction. Set the parameters for the expected upper limit Max and the expected lower limit Min.

Parameters of the expected value upper limit Max and the expected value lower limit Min are the time constant of the CR circuit by the capacitor 10 of the filter 8, the capacitor 14a for sample and hold of the A / D converter 14 and the resistor 19 or 20, and these CR circuits. It is set to a value in consideration of factors of variations due to tolerance of element values to be configured, quantization error of A / D conversion, and temperature characteristics.
For example, the expected value upper limit Max and the expected value lower limit Min of the diagnostic input 1 indicate the upper limit and the lower limit when the diagnostic pulse signal is output from the port IO1 to the input port In1, and the expected value upper limit Max and the expected value lower limit of the diagnostic input 2 Min indicates the upper limit and the lower limit when the diagnostic pulse signal is output from the port IO2 to the input port In1, but these values are set to different values according to the circuits of the respective energization paths.
For example, when the resistance value of the resistor 19 is larger than that of the resistor 20, the time constant of the CR circuit by the resistor 19 and the capacitor 10 becomes larger than the time constant of the CR circuit by the resistor 20 and the capacitor 10, as shown in FIG. As shown, the expected value upper limit Max and the expected value lower limit Min of the diagnostic input 1 are lower than the expected value upper limit Max and the expected value lower limit Min of the diagnostic input 2 as the limit value.

  When the CPU 11 falls within the expected range between the expected value lower limit Min and the expected value upper limit Max, both are determined as NO in S27 and S28 of FIG. 4 and shifts to the process of S30 as it is, but either S27 or S28 Since the value is out of the expected range between the expected value lower limit Min and the expected value upper limit Max when the condition is satisfied, the process is shifted to S30 after the return value is set to be abnormal in S29.

  Then, the CPU 11 increments the variable j in S30, returns the process to S26, and repeats the process of confirming whether or not the number of samples has been secured. If the variable j reaches the number of samples, the CPU 11 determines that the number of samples can be secured, ends sampling in S31, ends output of a diagnostic value in S32, and returns a return value.

<Detailed operation example>
FIG. 6 is a timing chart showing changes in voltages and the like of each of the ports IO1 and IO2 when sampling diagnosis is performed once. As shown in FIG. 6, during the normal control period T1, the diagnostic ports IO1 and IO2 are set to be in the high impedance state by being set by the CPU 11 as an input. The x marks of the ports IO1 and IO2 in FIG. 6 indicate the high impedance state. At this time, the output signal of the sensor device 2 is input to the input port In1, and the A / D converter 14 samples the output value of the sensor device 2 in accordance with the generation trigger of the sampling trigger generation unit 18. It is not affected by the resistors 19 and 20 connected in series to the ports IO1 and IO2.

When the abnormality detection processing shown in FIG. 2 is started, the CPU 11 outputs 0 V by the timer 12 for a certain period of time with the port (for example, IO1) set as an output in S22 of FIG. As a result, the charge stored in the sample hold capacitor 14 a of the A / D converter 14 can be discharged to reduce the capacitor stored voltage Vc to 0V. See interval period Ti in FIG. Then, the CPU 11 outputs a one-shot pulse of 5 V as a pulse for diagnosis through the timer 12 under the control of the pulse output control unit 16 for diagnosis, and the A / D sampling determination unit 17 performs sampling diagnosis.
At this time, the CPU 11 and the timer 12 output a waveform of a fixed time of 0 V and a waveform of a one-shot pulse of 5 V, and start output from the port IO1 in S23 of FIG. See control period T2 of port IO1 in FIG.

When the microcomputer 7 outputs a one-shot pulse from the port IO1 for diagnosis, the sample / hold capacitor 14a of the A / D converter 14 receives a duller voltage according to the CR time constant. 4 performs a diagnostic process by comparing the diagnostic sampling value obtained by sampling the input signal voltage in S27 to S30 of FIG. 4 with the expected value upper limit Max and the expected value lower limit Min.
That is, in the case of the flow shown in FIG. 4, the initial value is maintained as normal when it is within the expected range between the expected value upper limit Max and the expected value lower limit Min, but it returns when it deviates from the expected range even by one. Change the value from the initial value of normal to abnormal. The microcomputer 7 repeats the processing of S27 to S30 of FIG. 4 by the number of samples of the one-shot pulse of the diagnostic pulse signal, and repeats the sampling at S31 when the number of samples is repeated, and the port output ends at S32, and the set return Return the value.

  Then, as shown in a period T3 of FIG. 6, the microcomputer 7 executes the same process as that of FIG. 4 after changing the setting of the port from IO1 to IO2. For example, when the time constant of the CR low pass filter circuit 21 in the conduction path from the port IO2 to the port In1 is different from the time constant of the CR low pass filter circuit 21 in the conduction path from the port IO1 to the port In1 shown in FIG. As described above, both the expected value upper limit Max and the expected value lower limit Min are changed, the contents are executed as in the process of FIG. 4, and the return value after the end of sampling is similarly returned. In this case, the parameter can be changed to determine whether the sampling interval is abnormal or normal, and the reliability of the abnormality determination can be improved.

As shown in FIG. 2, the microcomputer 7 repeats these processes until the number of sampling diagnoses is reached, and determines that the return value is normal if the number of times the return value is normal exceeds the normal determination number threshold, otherwise it is abnormal It is determined that
In FIG. 2, when the microcomputer 7 sets the normal determination number threshold to 1 and determines that at least one of the sampling diagnosis results is normal, it is determined that the sampling interval is not abnormal, that is, normal. You may In this case, the processing can be simplified.

<Description of Comparative Example>
Generally, the failure rate of the external monitoring unit is higher than the failure rate of the microcomputer, and the CR circuit is truly considered in consideration of the variation of the circuit components and the temperature characteristics when judging the appropriateness of the CR circuit. Uncertainty increases with proper operation. For this reason, even if it applies the technique of patent document 1, for example, appropriate diagnosis of a sampling interval can not be performed appropriately.

<Conceptual summary of this embodiment, effect>
According to the present embodiment, the CPU 11 of the microcomputer 7 outputs the diagnostic pulse signal by the one-shot trigger to the A / D converter during the period outside the normal operation period T1 of the A / D converter 14 at T2 and T3. The analog signal is input to the input section of 14, and the sampling value obtained each time the A / D converter 14 samples the analog signal in a plurality of times divided is a predetermined expected value upper limit Max and an expected value lower limit defined for each sampling A sampling diagnosis is performed to determine whether it falls within the expected range between Min and Min, and it is determined whether the sampling interval is abnormal according to the sampling diagnosis result.
By performing such processing, if it can be determined that the sampling interval is normal, it is possible to guarantee that the sampling interval by the timer interrupt generated by the sampling trigger generation unit 18 is appropriate. In particular, even when AD conversion data is used for control processing to which the functional safety standard ISO26262 of the automotive field is applied, it is ensured that the sampling interval by the timer interrupt generated by the sampling trigger generation unit 18 is appropriate. it can.
The microcomputer 7 sets the sampling diagnosis count and the normal determination count threshold according to the parameter that causes the variation in the input path of the A / D converter 14, so the microcomputer 7 responds to the set value changed according to the parameter. It becomes possible to determine whether or not the sampling interval is abnormal, and as a result, the detection performance can be improved and the possibility of false detection can be reduced. Further, since the time constant of the CR low pass filter circuit 21 is changed to determine whether the sampling interval is normal or abnormal, it is possible to further improve the reliability of normal / abnormal judgment.

Second Embodiment
7 and 8 show additional explanatory diagrams of the second embodiment. FIG. 7 is a flowchart showing the flow of the abnormality detection process shown in place of FIG. 2, and FIG. 8 shows a method of setting the sampling diagnosis number and the abnormality determination number threshold value in place of FIG. In the abnormality detection process of FIG. 2 of the first embodiment, it is determined whether the sampling interval is normal or abnormal according to the comparison between the normal counter and the normal determination number threshold value. In the abnormality detection process, an abnormality counter is separately provided instead of the normal counter, and it is determined whether the sampling interval is normal or abnormal according to comparison between the abnormality counter and the abnormality determination number threshold value.

That is, the microcomputer 7 executes, for example, the sampling diagnosis process shown in FIG. 4 and increments the abnormality counter in S7a when the return value is abnormal, and repeats until the number of diagnoses reaches the number of sampling diagnoses. When the number of times of abnormality determination exceeds the threshold value, it is determined in S10 that the state is abnormal. As a result, when the number of abnormality determinations increases, it can be determined as an abnormality.
Further, in the process of FIG. 7, by setting the abnormality determination frequency threshold equal to the sampling diagnosis frequency, the sampling interval is determined to be abnormal if all sampling diagnosis results are not normal, ie, even if one sampling diagnosis result is not normal When it is determined that the sampling interval is determined to be abnormal, it may be determined that the sampling interval is abnormal. The diagnosis can be simplified by performing such a diagnosis process.

  As described in the first embodiment, it is desirable to set the normal judgment frequency threshold to the sampling diagnosis frequency to 1/2 or less. Conversely, as shown in FIG. 8, the abnormality judgment frequency threshold to the sampling diagnosis frequency is It is desirable to make the value more than 1/2. This is because even if the diagnostic circuit is in an abnormal state, the diagnostic process can be continued using another diagnostic circuit.

Further, the higher the environmental temperature is, the greater the cause of variation in the characteristics of the CR circuit. Therefore, it is desirable to increase the number of times of sampling diagnosis and raise the detection accuracy as the temperature is higher. Further, as the sampling cycle at the time of diagnosis is larger, the deviation of the detection value according to the tolerance of the element value is also larger, so the accuracy is preferably made relatively low, and the abnormality determination number threshold may be made large. This makes it possible to diagnose whether or not the sampling process is appropriate within the range where false detection is not made.
According to the present embodiment, even if an abnormality counter is provided instead of the normal counter, the same operation and effect as the first embodiment can be obtained.

Third Embodiment
FIG. 9 shows an additional explanatory view of the third embodiment. FIG. 9 is a flowchart showing the flow of the abnormality detection process shown in place of FIG. 2 or 7. In the abnormality detection process of FIG. 2 of the first embodiment, it is determined whether normal or abnormal according to the comparison between the normal counter and the normal determination number threshold value, but in the abnormality detection process of FIG. 9 of the third embodiment. An abnormality counter is provided together with the normal counter, and it is determined whether sampling is normal or sampling abnormality according to the comparison between the normal counter and the abnormality counter.

  Here, after the CPU 11 repeats the processing of S1b to S7a until the number of sampling diagnoses is reached, as shown in S8b of FIG. 9, when the normal counter is larger than the abnormal counter, the sampling interval is determined as normal in S9 and normal When the counter is equal to or less than the abnormal counter, the sampling interval is determined to be abnormal at S10. That is, when the number of times the sampling diagnosis result is not abnormal exceeds the number of times of being abnormal, it is determined that the sampling interval is not abnormal. Also in such a mode, the same function and effect as those of the above-described embodiment can be obtained.

(Other embodiments)
The present invention is not limited to the above embodiment, and for example, the following modifications or expansions are possible.
Although the circuit from the ports IO1 and IO2 to the input port In1 is configured by the CR low pass filter circuit 21, any type of circuit (for example, a passive circuit) may be used. When the CR low pass filter circuit 21 is used as a circuit from the plurality of output ports IO1 and IO2 to the input port In1, the time constants may be the same or different. Although the form which made the one-shot trigger the diagnostic pulse signal was shown, the diagnostic pulse signal output during period T2 or T3 of FIG. 6 may be not one pulse but multiple pulses, for example. In the determination method of sampling diagnosis of FIG. 4, even if it is determined that at least one sampling result is out of the expected range, it may be determined as abnormal.

  It is also possible to combine the configuration and processing contents of the above-described embodiment. Further, reference numerals in parentheses described in the claims indicate the correspondence with the specific means described in the embodiment described above as one aspect of the present invention, and the technical scope of the present invention It is not limited. The aspect which abbreviate | omitted a part of above-mentioned embodiment as long as a subject can be solved can also be considered as embodiment. In addition, any conceivable aspect can be considered as an embodiment without departing from the essence of the invention specified by the language described in the claims.

  Furthermore, although the present invention has been described based on the above-described embodiment, it is understood that the present invention is not limited to the embodiment or the structure. The invention also encompasses variations and modifications within the equivalent range. In addition, various combinations and forms as well as other combinations and forms including one element or more or less or less are also within the scope and the scope of the present disclosure.

  In the drawing, 1 is an electronic control unit, 7 is a microcomputer, 14 is an A / D converter, 16 is a diagnostic pulse signal output control unit, 17 is an A / D sampling determination unit (abnormality determination unit), 22 is a diagnostic pulse signal output Show.

Claims (7)

An electronic control unit (1) comprising an A / D converter (14) for inputting an analog signal to an input unit and performing A / D conversion,
A diagnostic pulse signal output unit (22) for outputting a diagnostic pulse signal to an input unit of the A / D converter;
The diagnostic pulse signal output unit outputs a diagnostic pulse signal during a period outside the normal operation period of the A / D converter to input the analog signal to the input unit of the A / D converter, Whether the sampled value obtained each time the A / D converter samples the analog signal in a plurality of times falls within an expected range between a predetermined expected upper limit and an expected lower limit defined for each sampling And an abnormality discrimination unit (17) which performs sampling diagnosis to determine whether the sampling interval is abnormal or not according to the result of the sampling diagnosis.
An electronic control unit comprising:   The abnormality determination unit is a sampling diagnosis number indicating the number of times the sampling diagnosis is performed, and a normal determination which determines that the abnormality determination unit is not a sampling abnormality among the sampling diagnosis number, or an abnormality determination which determines a sampling abnormality A determination frequency threshold indicating a threshold value of the frequency is set according to a parameter that causes variation in the input path of the A / D converter, and it is determined whether or not the sampling interval is abnormal according to the setting value. The electronic control device according to claim 1.   The electronic control unit according to claim 1, wherein the abnormality determination unit determines that the sampling interval is abnormal when it determines that the sampling diagnosis result is not normal even once.   The electronic control unit according to claim 1, wherein the abnormality determining unit determines that the sampling interval is not abnormal when it determines that the sampling diagnosis result is normal even once.   The electronic control unit according to claim 1, wherein the abnormality determination unit determines that the sampling interval is not abnormal when the number of times the sampling diagnosis result is not abnormal exceeds the number of times the abnormality is abnormal.   The electronic according to any one of claims 1 to 5, further comprising a CR low pass filter circuit (21) configured between an output node of the diagnostic pulse signal output unit and an input node of the A / D converter. Control device.   The electronic control unit according to claim 6, wherein the abnormality determination unit determines the abnormality by changing a time constant of the CR low pass filter circuit.

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