JP2020036095A - Pulse signal abnormality detection device - Google Patents

Abstract

To provide a pulse signal abnormality detection device capable of detecting an abnormality of a pulse signal whose frequency changes.SOLUTION: An abnormality detection unit 14 performs in parallel: a first abnormality determination method for performing an abnormality determination on the basis of whether a pulse edge count value for counting the number of edges of a pulse signal and a monitor edge count value for counting the number of edges of a monitor signal for monitoring the pulse signal matches; and a second abnormality determination method for performing abnormality determination on the basis of whether a level of the pulse signal and a level of the monitor signal correspond to each other. Therefore, it is possible to detect abnormality of the pulse signal regardless of the frequency of the pulse signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pulse signal abnormality detection device that detects abnormality of a pulse signal whose frequency changes.

  For example, in Patent Document 1, a pulse signal having a predetermined cycle is input from the outside to a microcomputer, and the microcomputer measures the cycle of the input pulse signal. When the measured cycle is out of a predetermined range. Discloses an electronic control system for a vehicle that diagnoses an abnormality in a timer function of a microcomputer.

JP 2002-89336 A

  Here, a plurality of microcomputers may be provided in a vehicle electronic control system or a relatively large-scale electronic control system. When the electronic control system includes a plurality of microcomputers, for example, a sensor signal from a rotation sensor that detects rotation of a wheel or an axle, rotation of an engine, or rotation of a device to be controlled must be available to two or more microcomputers. May be required.

  As an example of a configuration for achieving this, a specific microcomputer inputs, from a rotation sensor, a pulse signal whose frequency changes in accordance with the rotation of the detection target, and outputs another pulse signal corresponding to the input pulse signal. Output to the microcomputer. However, when a specific microcomputer is configured to relay a pulse signal to another microcomputer in this way, if the intended microcomputer does not output the intended pulse signal to the other microcomputer, an appropriate electronic control system is required. Control cannot be performed. Therefore, it is important to accurately detect whether a pulse signal output from a specific microcomputer is a normal pulse signal as intended or an abnormal pulse signal different from the intended one.

  Also, when the microcomputer outputs, for example, a pulse signal whose frequency changes as a drive signal for driving the controlled device, if the intended pulse signal is not output from the microcomputer, the controlled device is targeted. Can't control. Therefore, also in this case, it is important for the microcomputer to accurately detect whether a normal pulse signal is output as intended or an abnormal pulse signal different from the intended one is output.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a pulse signal abnormality detection device capable of detecting abnormality of a pulse signal whose frequency changes.

In order to achieve the above object, a pulse signal abnormality detection device according to the present invention includes:
An output unit (13) for outputting a pulse signal whose frequency changes,
An abnormality detection unit (14) for performing abnormality detection using a monitor signal that monitors a pulse signal output from the output unit;
The abnormality detector is
A first abnormality determination unit (S100 to S140) for performing an abnormality determination based on whether a pulse edge count value for counting the number of edges of the pulse signal matches a monitor edge count value for counting the number of edges of the monitor signal; When,
A second abnormality determining unit (S600 to S650) for performing abnormality determination based on whether or not the level of the pulse signal corresponds to the level of the monitor signal;
The abnormality determination by the first abnormality determination unit and the second abnormality determination unit is performed in parallel.

  In the pulse signal abnormality detection device according to the present invention, as described above, the abnormality detection unit includes the first abnormality determination unit and the second abnormality determination unit, and the first abnormality determination unit and the second abnormality determination unit operate in parallel. It is configured to execute abnormality determination. When the frequency of the pulse signal is relatively high and an edge occurs at a relatively short time interval, the first abnormality determination unit mainly determines the presence or absence of the abnormality of the pulse signal based on the number of edges that occur frequently. Further, when the frequency of the pulse signal decreases and the time interval at which the edge of the pulse signal occurs increases, the second abnormality determination unit mainly determines the presence or absence of the abnormality of the pulse signal based on the level of the monitor signal. . Therefore, it is possible to detect abnormality of the pulse signal regardless of the frequency of the pulse signal.

  The reference numbers in the parentheses are merely an example of a correspondence relationship with a specific configuration in the embodiment described later in order to facilitate understanding of the present disclosure, and are intended to limit the scope of the invention. It was not done.

  Further, technical features described in each claim of the claims other than the above-described features will be apparent from the description of the embodiments and the accompanying drawings described later.

1 is a configuration diagram illustrating an example of a configuration when a pulse signal abnormality detection device according to an embodiment is applied to a vehicle control system. 5 is a flowchart illustrating a main routine for an abnormality detection unit to execute a first abnormality determination method. FIG. 3 is a flowchart showing details of an abnormal process in the flowchart of FIG. 2. 9 is a flowchart illustrating a process for restarting the output of the output pulse signal when the abnormality detection unit stops the output pulse signal. In the first abnormality determination method, a first ground short abnormality determination result and a first power short abnormality determination result are obtained from values stored in a first ground short determination storage unit and a first power short determination storage unit. It is a flowchart which shows a process. 5 is a timing chart for explaining a first abnormality determination method. 5 is another timing chart for describing a first abnormality determination method. 10 is a flowchart illustrating a process in which an abnormality detection unit starts a timer when an edge is detected in order to determine the arrival of a timing for executing a second abnormality determination method. It is a flowchart which shows the main routine of the 2nd abnormality determination method. 10 is a flowchart showing details of the abnormal time process of the flowchart of FIG. 9. In the second abnormality determination method, a second ground short abnormality determination result and a second power short abnormality determination result are obtained from values stored in the second ground short determination storage unit and the second power short determination storage unit. It is a flowchart which shows a process. 6 is a timing chart for explaining a second abnormality determination method. 9 is another timing chart for describing a second abnormality determination method.

  Hereinafter, a pulse signal abnormality detection device according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration example when the pulse signal abnormality detection device according to the present embodiment is applied to a vehicle control system.

  The vehicle control system shown in FIG. 1 includes an engine rotation sensor (crank angle sensor) 1 for detecting engine rotation. The engine rotation sensor 1 outputs a pulse signal every time the crankshaft of the engine rotates a predetermined angle. Therefore, the frequency of the pulse signal output from the engine rotation sensor 1 changes according to the engine speed.

  The pulse signal output from the engine rotation sensor 1 is input to the engine control ECU 10. The engine control ECU 10 has a microcomputer 11, and the microcomputer 11 calculates an engine rotation speed based on a pulse signal from the engine rotation sensor 1. In addition, the microcomputer 11 acquires the engine coolant temperature, the driver's accelerator operation, the vehicle speed, and the like from sensor signals from various sensors. Based on the calculated engine rotation speed, driver's accelerator operation, and the like, the microcomputer 11 sends, for example, to a fuel injection valve provided in each cylinder of the engine or a throttle motor that drives a throttle valve provided in an intake pipe. Outputs control signal. In this way, the engine control ECU 10 controls the fuel injection amount, the fuel injection timing, the throttle opening, and the like of the engine according to the operating state of the engine, which is grasped from the engine rotation speed and the like, and the driving operation by the driver.

  As described above, the microcomputer 11 of the engine control ECU 10 appropriately controls the engine by generating a control signal for outputting to an actuator such as a fuel injection valve or a throttle motor based on a sensor signal of the engine rotation sensor 1 or the like. The system includes a CPU 12 that executes a control process for operation, and a TPU (Time Processing Unit) 13 that mainly processes a pulse signal input from the engine rotation sensor 1.

  The TPU 13 will be described in further detail. The TPU 13 has a function of detecting at least one of a rising edge and a falling edge of an input pulse signal and measuring a time interval between the detected edges. The CPU 12 of the microcomputer 11 calculates the engine speed based on the time interval between edges measured by the TPU 13. Further, the TPU 13 generates an inverted pulse signal obtained by inverting the level of the pulse signal input from the engine rotation sensor 1 and outputs the inverted pulse signal as an output pulse signal, such as a transmission control ECU 20 that requires an engine rotation speed to execute control. It has a function to output to other ECUs. The inverted pulse signal may be generated by a hardware circuit or may be generated by a software process.

  As described above, the vehicle control system shown in FIG. 1 is configured such that the TPU 13 of the microcomputer 11 outputs an output pulse signal obtained by inverting the level of the input pulse signal from the engine rotation sensor 1 to another ECU. That is, the TPU 13 of the microcomputer 11 is configured to relay the pulse signal from the engine rotation sensor 1 to another ECU. In this case, if the TPU 13 does not output a normal output pulse signal correctly corresponding to the input pulse signal, the ECU that has received the output pulse signal cannot execute appropriate control. Therefore, the TPU 13 has an abnormality detection unit 14 that captures the output pulse signal as a monitor signal and detects whether the output pulse signal is normal or abnormal based on the monitor signal. When detecting that the output pulse signal is abnormal, the abnormality detection unit 14 notifies another ECU that uses the output pulse signal of the abnormality. This allows other ECUs using the output pulse signal to take appropriate measures.

  In the present embodiment, the TPU 13 uses a signal obtained by inverting the level of the received output pulse signal as a monitor signal. This level inversion may be performed by either hardware or software. However, the TPU 13 may directly output the input pulse signal as the output pulse signal without performing the level inversion described above, and / or may use the output pulse signal as it is as the monitor signal.

  Hereinafter, the abnormality detection unit 14 of the TPU 13 will be described in detail with reference to the flowcharts of FIGS. 2 to 5 and FIGS. 8 to 10 and the timing charts of FIGS.

  The abnormality detection unit 14 detects whether the output pulse signal is normal or abnormal based on whether the number of edges of the input pulse signal matches the number of edges of the monitor signal in order to detect an abnormality of the output pulse signal. A first abnormality determination method for determining whether the output pulse signal is present, and determining whether the output pulse signal is normal or abnormal based on whether the level of the input pulse signal corresponds to the level of the monitor signal. And a second abnormality determination method. That is, the abnormality detection unit 14 detects an abnormality of the output pulse by the first and second abnormality determination methods, and the first and second abnormality determination methods are executed in parallel. Then, when an abnormality is determined by one of the first abnormality determination method and the second abnormality determination method, the abnormality detection unit 14 performs abnormality detection based on the result determined earlier.

  In the case where the frequency of the input pulse signal is relatively high and edges occur at relatively short time intervals, the first abnormality determination method allows the output pulse signal to be correctly and accurately determined based on the number of frequently occurring edges. Or abnormal. Further, even when the frequency of the input pulse signal decreases and the time interval at which the edge of the input pulse signal occurs becomes longer, the output pulse signal is obtained by using the level of the monitor signal by the second abnormality determination method. Is normal or abnormal. Therefore, the abnormality detection unit 14 can detect the abnormality of the output pulse signal in a timely manner regardless of the frequency of the input pulse signal.

  In order to execute the first abnormality determination method, the abnormality detector 14 counts the number of edges of the input pulse signal and the number of edges of the monitor signal, for example, as shown in FIG. And a monitor edge counter. In the example shown in FIG. 6, the pulse edge counter and the monitor edge counter count the falling edge of the input pulse signal and the falling edge of the monitor signal, respectively. In other words, the pulse edge counter and the monitor edge counter count up after a predetermined delay time after the falling edge of the input pulse signal and the falling edge of the monitor signal are detected, respectively.

  Note that the pulse edge counter and the monitor edge counter may count the rising edge of the input pulse signal and the rising edge of the monitor signal, respectively, or may count both edges of the input pulse signal and both edges of the monitor signal. Good. In the pulse edge counter, the pulse signal whose edge is to be counted may be an output pulse signal output from the TPU 13 instead of the input pulse signal.

  When the pulse edge counter of the abnormality detection unit 14 counts the number of edges of the input pulse signal, when the first abnormality determination method causes a mismatch with the number of edges of the monitor signal, the TPU 13 Due to the output pulse signal generation processing, the output pulse signal output path, the monitor signal input path, the monitor signal generation processing in the TPU 13, or the abnormality of the pulse edge counter and / or the monitor edge counter, the output pulse signal It can be determined that an abnormality has occurred or that an abnormality in the output pulse signal cannot be detected. On the other hand, when the pulse edge counter of the abnormality detection unit 14 counts the number of edges of the output pulse signal, when the first abnormality determination method causes a mismatch with the number of edges of the monitor signal, The output pulse signal is abnormal due to the output path of the output pulse signal, the input path of the monitor signal, the generation processing of the monitor signal, or the abnormality of the pulse edge counter and / or the monitor edge counter, or the output pulse is abnormal. It can be determined that the signal abnormality cannot be detected.

  The abnormality detection unit 14 further includes a first ground short (GS) determination storage unit and a first power supply short (PS) determination storage unit to execute the first abnormality determination method. As shown in FIG. 6, the abnormality detection unit 14 reads the count value of the pulse edge counter and the count value of the monitor edge counter and triggers the detection by detecting the edge (falling edge) of the input pulse signal. I do. The read count value is a count value before the pulse edge counter and the monitor edge counter count up based on detection of the falling edge of the input pulse signal and the falling edge of the monitor signal.

  If the count value of the pulse edge counter to be compared with the count value of the monitor edge counter matches, it can be considered that the output pulse signal is normally output. Therefore, when the count value of the pulse edge counter and the count value of the monitor edge counter match, the abnormality detection unit 14 performs, for example, as shown at times t2 and t5 in the timing chart of FIG. A value “0” indicating that the output pulse signal is normal is written in the 1-ground short (GS) determination storage unit and the first power supply short (PS) determination storage unit.

  On the other hand, when the abnormality detection unit 14 reads the count value of the pulse edge counter and the count value of the monitor edge counter and compares them, if the two count values do not match, some abnormality may have occurred in the output pulse signal. There is. At this time, the abnormality detection unit 14 may simply determine that the output pulse signal is abnormal, but the abnormality detection unit 14 of the present embodiment further determines that the cause of the abnormality is a pulse edge counter and / or a monitor edge counter. It is configured to determine whether there is an abnormality, a ground short abnormality in the output path of the output pulse signal or the input path of the monitor signal, or a power short circuit. A method of determining whether the ground short-circuit is abnormal and the power short-circuit is abnormal will be described later. When the abnormality detecting unit 14 determines that the ground short has occurred, the first ground short determination storage unit stores a value “1” indicating the occurrence of the ground short abnormality in the first ground short determination storage unit, for example, as shown at time t11 in the timing chart of FIG. Write. When it is determined that the power supply is short-circuited, a value “1” indicating the occurrence of the power supply short-circuited abnormality is written into the first power supply short-circuit determination storage unit.

  Further, as shown in FIG. 6, the abnormality detecting unit 14 of the present embodiment, the first ground short determination storage unit and the first power short determination storage unit at predetermined time intervals (read cycle) T2 (for example, 100 ms). The values stored in the first and second sections are read out and used as a first ground short abnormality determination result and a first power supply short abnormality determination result. After reading the values stored in the first ground short determination storage and the first power short determination storage, the abnormality detector 14 reads the values stored in the timing chart of FIG. 6 at times t0, t4, t7, and t12. A value “2” different from the value “0” indicating normal and the value “1” indicating occurrence of abnormality is set as an initial value. Therefore, when the value stored in the first ground short determination storage unit and the first power short determination storage unit after the predetermined time interval T2 elapses and the value is still “2”, it is normal. It can be grasped that neither the judgment nor the abnormality judgment is made.

  On the other hand, in order to execute the second abnormality determination method, the abnormality detection unit 14 includes a pulse level latch unit that latches the level of the input pulse signal and a monitor that latches the level of the monitor signal, as shown in FIG. And a level latch unit. The input pulse signal and the monitor signal change between Hi level and Lo level, respectively. Therefore, the level latched by the pulse level latch section and the monitor level latch section is either the Hi level or the Lo level according to the level change of the input pulse signal and the monitor signal. Note that there is a predetermined delay time from when the levels of the input pulse signal and the monitor signal change to when the levels latched by the pulse level latch section and the monitor level latch section change. Further, these level latch units may be omitted, and the abnormality detection unit 14 may be configured to directly read the levels of the input pulse signal and the monitor signal. Further, as a target to be compared with the level of the monitor signal, an output pulse signal output from the TPU 13 may be used instead of the input pulse signal.

  The abnormality detection unit 14 further includes a second ground short (GS) determination storage unit and a second power supply short (PS) determination storage unit in order to execute the second abnormality determination method. As shown in FIG. 12, the abnormality detection unit 14 uses the detection of an edge (falling edge and falling edge) in the input pulse signal as a trigger, and the level latched by the pulse level latch unit and the monitor level latch unit. Is read and compared.

  When the level latched by the pulse level latch unit and the level latched by the monitor level latch unit correspond (match) with the Hi level of the monitor signal, at least the output path of the output pulse signal and the monitor signal It is considered that no ground short circuit has occurred in the input path. Therefore, in this case, as shown at time t34 in the timing chart of FIG. 12, the abnormality detection unit 14 writes a value “0” indicating that the output pulse signal is normal to the second ground short determination storage unit. Further, when the level latched by the pulse level latch unit and the level latched by the monitor level latch unit correspond (match) with the Lo level of the monitor signal, at least the output path of the output pulse signal and the monitor It is considered that no power short-circuit abnormality has occurred in the signal input path. Therefore, in this case, as shown at time t36 in the timing chart of FIG. 12, the abnormality detection unit 14 writes a value “0” indicating that the output pulse signal is normal to the second power supply short determination storage unit.

  Conversely, if the level latched by the compared pulse level latch unit and the level latched by the monitor level latch unit do not correspond (coincide) and the level of the monitor signal is Lo level, the output pulse signal It is considered that a ground short abnormality has occurred in one of the output path and the input path of the monitor signal. Therefore, in this case, the abnormality detection unit 14 writes the value “1” indicating that the output pulse signal is abnormal to the second ground short determination storage unit. Further, when the level latched by the pulse level latch unit to be compared does not correspond (coincide) with the level latched by the monitor level latch unit, and the level of the monitor signal is Hi level, It is considered that a power short-circuit abnormality has occurred in either the output path or the input path of the monitor signal. Therefore, in this case, as shown at time t40 in the timing chart of FIG. 12, the abnormality detection unit 14 writes a value “1” indicating that the output pulse signal is abnormal to the second power supply short determination storage unit.

  As shown in the timing chart of FIG. 12, the abnormality detecting unit 14 is connected to the second ground short determination storage unit and the second ground short determination storage unit at predetermined time intervals (reading cycles) T2, as in the case of the first abnormality determination method. The values stored in the power-supply-short-determination storage unit are read out and used as a second ground short-circuit abnormality determination result and a second power-supply shortage abnormality determination result. After reading the values stored in the second ground short determination storage unit and the second power short determination storage unit, the abnormality detection unit 14 determines whether the values are normal as shown at times t30, t37, and t44 in the timing chart of FIG. The initial value is set to a value "2" different from the value "0" indicating that the value is "1" and the value "1" indicating the occurrence of abnormality.

  Next, the first abnormality determination method will be described in more detail with reference to flowcharts of FIGS. 2 to 5 and timing charts of FIGS. FIG. 2 is a flowchart showing a main routine for executing the first abnormality determination method. FIG. 3 is a flowchart showing details of the abnormal time process of the flowchart of FIG. FIG. 4 is a flowchart illustrating a process for restarting the output of the output pulse signal when the abnormality detection unit 14 stops the output pulse signal. FIG. 5 is a diagram illustrating a first ground short abnormality determination result and a first power short abnormality determination result based on values stored in the first ground short determination storage unit and the first power short determination storage unit in the first abnormality determination method. 5 is a flowchart showing a process for obtaining the.

  The process shown in the flowchart of FIG. 2 is started when the falling edge of the input pulse signal is detected. In the first step S100, the count value (PEC) of the pulse edge counter and the monitor edge count value (MEC) are read. At the time of reading these count values, the edge pulse counter has not counted up based on the detected edge of the input pulse signal.

  In a succeeding step S110, it is determined whether or not the read count value of the pulse edge counter is 0. When the count value of the pulse edge counter is 0, it is unknown whether or not the pulse edge counter normally counts the number of falling edges of the input pulse signal. Therefore, if the count value of the pulse edge counter is determined to be “0” in step S110, the process shown in the flowchart of FIG. 2 is performed without determining whether the output pulse signal is normal or abnormal. finish. In this case, as shown at time t1 in the timing chart of FIG. 6, the values of the first ground short determination storage unit and the first power short determination storage unit are maintained without being rewritten from the initial value “2”. Is done. On the other hand, if it is determined in step S110 that the count value of the pulse edge counter is not “0”, the process proceeds to step S120.

  In step S120, it is determined whether or not the read count value of the pulse edge counter matches the count value of the monitor edge counter. If it is determined that they do not match, the process proceeds to step S130, and if it is determined that they match, the process proceeds to step S140.

  In step S130, it is considered that some abnormality has occurred in the output pulse signal output from the TPU 13, so that the abnormality processing is performed. On the other hand, in step S140, the count value of the pulse edge counter matches the count value of the monitor edge counter, and it can be considered that the output pulse signal is normally output. As shown at t5, a value “0” indicating that the output pulse signal is normal is written into the first ground short determination storage unit and the first power short determination storage unit. At times t3 and t6, the count value of the pulse edge counter and the count value of the monitor edge counter match, but the first ground short determination storage unit and the first power short determination storage unit indicate that the normal state has already been established. The indicated value “0” has been written. Therefore, at times t3 and t6, the value “0” may be written, but the stored value may be maintained without writing any value.

  Next, the abnormal time process of step S130 will be described in detail with reference to the flowchart of FIG.

  In the first step S200, it is determined whether or not the count value of the pulse edge counter is larger than the count value of the monitor edge counter. In this determination processing, when it is determined that the count value of the pulse edge counter is larger than the count value of the monitor edge counter, the process proceeds to step S210, where the count value of the pulse edge counter is smaller than the count value of the monitor edge counter. Is determined, the process proceeds to step S270.

  If the count value of the pulse edge counter is larger than the count value of the monitor edge counter, either the output path of the output pulse signal or the input path of the monitor signal is ground shorted or the power supply is shorted, and the level of the monitor signal is Lo level or It may be fixed at the Hi level. When such an abnormality occurs, the TPU 13 may output an abnormal pulse signal. Therefore, in step S210, the abnormality detection unit 14 instructs the TPU 13 to stop the output pulse signal.

  For example, as shown in the timing chart of FIG. 6, when a ground short abnormality occurs in the input path of the monitor signal at a timing close to time t5, the level of the monitor signal is fixed to Lo level at that time. As a result, at time t8, the count value of the pulse edge counter does not match the count value of the monitor edge counter. Thereby, the abnormality detection unit 14 instructs the TPU 13 to stop the output pulse signal. In the example shown in FIG. 6, the abnormality detection unit 14 instructs the stop of the output pulse signal at time t10. That is, in the example shown in FIG. 6, the abnormality detection unit 14 instructs the stop of the output pulse signal when the count values do not match twice consecutively at time t8 and time t9. However, the abnormality detection unit 14 may instruct stop of the output pulse signal in response to one count value mismatch.

  In the following step S220, the process waits for a predetermined time T1 (for example, 1 ms) after stopping the output pulse signal. That is, it waits until the level fluctuation of the monitor signal due to the stop of the output pulse signal attenuates. Then, in step S230, at time t11 after the lapse of the predetermined time T1, the level latched by the monitor level latch unit is read. Then, in step S240, it is determined whether the level of the read monitor signal is Lo level or Hi level. In this determination process, when it is determined that the level is Lo, the process proceeds to step S250, and when it is determined that the level is Hi, the process proceeds to step S260.

  In step S250, since the level of the monitor signal is Lo level, it is highly likely that the output path of the output pulse signal and the input path of the monitor signal are short-circuited to ground. Therefore, as shown at time t11 in FIG. 6, the abnormality detection unit 14 writes a value “1” indicating a ground short abnormality in the first ground short determination storage unit. On the other hand, in step S260, since the level of the monitor signal is the Hi level, it is highly likely that the output path of the output pulse signal and the input path of the monitor signal are short-circuited. Therefore, the abnormality detection unit 14 writes a value “1” indicating a power short-circuit abnormality in the first power short-circuit determination storage unit.

  In step S270, which is executed when it is determined in step S200 that the count value of the pulse edge counter is smaller than the count value of the monitor edge counter, the pulse edge counter and the monitor edge counter are cleared to "0". Normally, the count value of the monitor edge counter cannot be larger than the count value of the pulse edge counter, because the cause is considered to be an abnormality of the pulse edge counter and / or the monitor edge counter.

  When the output pulse signal from the TPU 13 is stopped in the above-described abnormal processing, the ECU using the output pulse signal cannot execute normal control. Accordingly, in this case, for example, control is performed such that only the limp-home running of the vehicle is permitted. However, there is no possibility that the TPU 13 returns to a state in which the output pulse signal can be output normally after the ground short-circuit abnormality or the power supply short-circuit abnormality of the monitor signal has temporarily occurred due to the influence of some foreign matter.

  Therefore, the abnormality detection unit 14 may cause the TPU 13 to restart the output of the output pulse signal in response to the predetermined restart condition being satisfied. The flowchart of FIG. 4 shows a process for restarting the output of such an output pulse signal. Further, the timing chart of FIG. 7 is a continuation of the timing chart of FIG. 6, and shows an operation in a case where the ground short abnormality has been resolved after the determination of the ground short abnormality.

  In the first step S300, it is determined whether a predetermined restart condition is satisfied. The predetermined restart conditions include, for example, a change in the level of the monitor signal while the output pulse signal is stopped, a request to restart the output pulse signal from an external ECU, or a change in the output pulse signal. It can be either that a predetermined time has elapsed since the stop. If it is determined in step S300 that the predetermined restart condition has been satisfied, the process proceeds to step S310 and the subsequent steps to instruct output restart of the output pulse signal.

  In step S310, both the count value of the pulse edge counter and the count value of the monitor edge counter are cleared to "0" as shown at time t21 in the timing chart of FIG. As a result, the two count values that have been mismatched are made to match. Then, in step S320, the abnormality detection unit 14 instructs the TPU 13 to restart the output pulse signal. Thus, the output of the output pulse signal from the TPU 13 is restarted as shown in FIG. If the TPU 13 has returned to a state in which the output pulse signal can be output normally, the number of edges of the input pulse signal matches the number of edges of the monitor signal as shown in FIG. , And the output of the output pulse signal is continued. On the other hand, if the abnormality continues even after the output pulse signal is restarted, the output pulse signal is immediately stopped by the first abnormality determination method described above. Therefore, it is possible to prevent the ECU using the output pulse signal from executing inappropriate control based on the abnormal output pulse signal.

  Next, in the first abnormality determination method, the abnormality detecting unit 14 determines the first ground short abnormality determination result and the first ground short abnormality determination result from the values stored in the first ground short determination storage unit and the first power short determination storage unit. The process for obtaining the power short-circuit abnormality determination result will be described with reference to the flowchart in FIG. The process shown in the flowchart of FIG. 5 is started and executed at predetermined time intervals (reading cycles) T2.

  In the first step S400, the values stored in the first ground short determination storage unit and the first power short determination storage unit are read. In the following step S410, both of the read values are “2”, that is, whether the normal determination or the abnormality determination has not been made, or not yet determined, or one of the read values is “1”, that is, the ground short abnormality or the power supply It is determined whether a short-circuit abnormality has been determined, or whether both of the read values are “0”, that is, neither a ground short-circuit abnormality nor a power supply short-circuit abnormality has occurred, and the output pulse signal has been determined to be normal. When it is determined that the ground short abnormality or the power short abnormality has been determined, the process proceeds to step S420. When it is determined that the output pulse signal is determined to be normal, the process proceeds to step S450. If it is determined that no determination has been made, the process proceeds to step S460.

  In step S420, it is determined which of the first ground short determination storage unit and the first power short determination storage unit stores the value indicating the abnormality. For example, as shown at time t12 in the timing chart of FIG. 6, when the value indicating the abnormality is stored in the first ground short determination storage unit, the process proceeds to step S430, and it is determined that the ground short is abnormal. At this time, as shown in FIG. 6, a power short-circuit abnormality may be determined based on the value of the first power short-circuit determination storage unit. Conversely, if the value indicating the abnormality is stored in the first power short determination storage unit, the process proceeds to step S440, and it is determined that the power short is abnormal.

  In step S450, the output pulse signal is determined to be normal, for example, as shown at times t4 and t7 in the timing chart of FIG. In addition, in step S460, it is determined that the state is normal or abnormal or indefinite as shown at times t20 and t22 in the timing chart of FIG. In the timing charts of FIGS. 6 and 7, such a determination result is represented by a value “0” indicating normal, a value “1” indicating abnormal, and a value “2” indicating indefinite.

  Finally, in step S470, as shown at times t0, t4, t7, and t12 in the timing chart of FIG. 6, the value is different from a value “0” indicating normality and a value “1” indicating occurrence of abnormality. The value “2” is set as an initial value in the first ground short determination storage and the first power short determination storage.

  Next, the second abnormality determination method will be described in more detail with reference to flowcharts of FIGS. 8 to 11 and timing charts of FIGS. FIG. 8 is a flowchart showing a process for starting a timer upon detecting an edge in order to determine the timing of executing the second abnormality determination method. FIG. 9 is a flowchart showing a main routine for executing the second abnormality determination method. FIG. 10 is a flowchart showing details of the abnormal time processing of the flowchart of FIG. FIG. 11 shows a second ground short abnormality determination result and a second power short abnormality determination result based on values stored in the second ground short determination storage unit and the second power short determination storage unit in the second abnormality determination method. 5 is a flowchart showing a process for obtaining the.

  The process shown in the flowchart of FIG. 8 is started when a rising edge or a falling edge of the input pulse signal is detected. In step S500 of the flowchart in FIG. 8, a timer is started to measure the elapsed time since the edge was detected. The timer is reset each time an edge of the input pulse signal is detected, and starts measuring the elapsed time again.

  The process shown in the flowchart of FIG. 9 is started when the elapsed time measured by the timer started by the flowchart of FIG. 8 reaches a predetermined time T1. That is, the second abnormality determination method is executed only when the interval between the detected edges is equal to or longer than the predetermined time T1, and when a new edge is detected before the predetermined time T1 has elapsed, the second abnormality determination method is performed. No abnormality determination method is executed. In other words, when the next level change occurs in the input pulse signal before the predetermined time T1 has elapsed after the level of the input pulse signal has changed, the abnormality detection unit 14 performs the input based on the second abnormality determination method. It is not determined whether or not the level of the pulse signal corresponds to the level of the monitor signal. Therefore, the second abnormality determination method determines whether the output pulse signal is normal or abnormal when the engine rotation speed is relatively low.

  In step S600 of the flowchart in FIG. 9, the level of the output pulse signal latched by the pulse level latch unit and the level of the monitor signal latched by the monitor level latch unit are read and compared. Note that the process of step S600 is performed after a predetermined time T1 has elapsed from the detection of the edge. Therefore, in step S600, the level of the output pulse signal and the level of the monitor signal after a lapse of a predetermined time T1 after the level of the output pulse signal changes are compared.

  In a succeeding step S610, it is determined whether or not the level of the output pulse signal and the level of the monitor signal correspond to each other (match). In this determination processing, if it is determined that the levels of both signals correspond, the process proceeds to step S620. On the other hand, if it is determined that the levels of the two signals do not correspond to each other, it is considered that some abnormality has occurred in the output pulse signal, and the process proceeds to step S650.

  In step S620, it is determined whether the level of the monitor signal is Hi level or Lo level. When the monitor signal is at the Hi level and corresponds to the level of the input pulse signal, it is considered that at least the ground short abnormality has not occurred in at least the output path of the output pulse signal and the input path of the monitor signal. Accordingly, when it is determined in step S620 that the level of the monitor signal is the Hi level, the process proceeds to step S630, and as shown at times t34 and t38 in the timing chart of FIG. A value “0” indicating that the output pulse signal is normal is written in the short determination storage unit.

  On the other hand, when the monitor signal is at the Lo level and corresponds to the level of the input pulse signal, it is considered that at least the power supply short circuit has not occurred in the output path of the output pulse signal and the input path of the monitor signal. Therefore, when it is determined in step S620 that the level of the monitor signal is Lo level, the process proceeds to step S640, and as shown at time t36 in the timing chart of FIG. A value “0” indicating that the output pulse signal is normal is written in the section.

  When the processing in step S630 or S640 is completed, the processing shown in the flowchart in FIG. 9 ends. After the processing of steps S630 and S640 is completed, the timer may be reset and restarted. In this manner, as shown at times t43 and t45 in the timing chart of FIG. 11, when the level of the input pulse signal does not change and no edge is detected, the level of the input pulse signal is increased every time the predetermined time T1 elapses. And whether the level of the monitor signal and the level of the monitor signal correspond to each other can be repeatedly executed.

  In step S650, since the level of the input pulse signal does not match the level of the monitor signal, an abnormal-time process is executed. Details of the abnormal time process will be described with reference to the flowchart of FIG.

  In the first step S700, it is determined whether the level of the monitor signal is Hi level or Lo level. If the level of the input pulse signal does not correspond to the level of the monitor signal and the level of the monitor signal is Lo level, a ground short circuit occurs in either the output path of the output pulse signal or the input path of the monitor signal. it seems to do. Therefore, if it is determined in step S700 that the monitor signal is at the Lo level, the process proceeds to step S710, and the abnormality detection unit 14 indicates to the second ground short determination storage unit that the output pulse signal is abnormal. Write the value "1".

  On the other hand, if the level of the input pulse signal does not correspond to the level of the monitor signal, and the level of the monitor signal is Hi level, a power supply short circuit is detected in either the output path of the output pulse signal or the input path of the monitor signal. Is considered to have occurred. Accordingly, if it is determined in step S700 that the monitor signal is at the Hi level, the process proceeds to step S720, and as shown at time t40 in the timing chart of FIG. The value “1” indicating that the output pulse signal is abnormal is written in the section.

  In the abnormality processing of FIG. 10, the output pulse signal may be stopped as in the abnormality processing of the first abnormality determination method.

  Next, in the second abnormality determination method, the abnormality detection unit 14 determines the second ground short abnormality determination result and the second ground short abnormality determination value from the values stored in the second ground short determination storage unit and the second power supply short determination storage unit. The process for obtaining the power short-circuit abnormality determination result will be described with reference to the flowchart in FIG.

  In the first step S800, the values stored in the first ground short determination storage unit and the first power short determination storage unit are read. In the following step S810, both of the read values are "2", that is, whether the normal determination or the abnormality determination has not been made, or not yet determined, or one of the read values is "1", that is, the ground short abnormality or the power supply It is determined whether a short-circuit abnormality has been determined, or whether both of the read values are “0”, that is, neither a ground short-circuit abnormality nor a power supply short-circuit abnormality has occurred, and the output pulse signal has been determined to be normal. When it is determined that the ground short abnormality or the power short abnormality has been determined, the process proceeds to step S820. When it is determined that the output pulse signal is determined to be normal, the process proceeds to step S850. If it is determined that the determination has not been made, the process proceeds to step S860.

  In step S820, it is determined which of the first ground short determination storage unit and the first power short determination storage unit stores the value indicating the abnormality. For example, as shown at time t44 in the timing chart of FIG. 12, when the value indicating the abnormality is stored in the second power short determination storage unit, the process proceeds to step S840, and it is determined that the power short is abnormal. At this time, as shown in FIG. 12, a normal ground shortage abnormality may be determined based on the value of the second ground short determination storage unit. Conversely, when the value indicating the abnormality is stored in the second ground short determination storage unit, the process proceeds to step S830, and it is determined that the ground short is abnormal.

  In step S850, the output pulse signal is determined to be normal, for example, as shown at time t37 in the timing chart of FIG. In step S860, as shown at time t30 in the timing chart of FIG. 12, it is determined that the state is normal, abnormal, or indeterminate. In the timing chart of FIG. 12, such a determination result is represented by a value “0” indicating normal, a value “1” indicating abnormal, and a value “2” indicating indefinite.

  Finally, in step S870, the abnormality detection unit 14 sets the value “0” indicating normality and the value “1” indicating occurrence of abnormality as shown at times t30, t37, and t44 in the timing chart of FIG. Is set as an initial value in the second ground short determination storage unit and the second power short determination storage unit.

  In the second abnormality determination method, when a power supply short-circuit abnormality occurs and the level of the monitor signal is fixed at the Hi level, and when the input pulse signal does not change from the Hi level, at least the ground short-circuit abnormality does not occur. However, it is not possible to determine that a power short-circuit abnormality has occurred. Conversely, as shown in the timing chart of FIG. 13, in the second abnormality determination method, when a power supply short-circuit abnormality occurs and the level of the monitor signal is fixed at the Hi level, the level of the input pulse signal becomes the Lo level. If so, it is possible to determine that a power short-circuit abnormality has occurred. The same applies to the determination of a ground short abnormality.

  As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and can be variously modified and implemented without departing from the gist of the present invention.

  For example, in the above-described embodiment, in the first abnormality determination method and the second abnormality determination method, it is determined whether the abnormality is a ground short abnormality or a power short abnormality. However, the first abnormality determination method simply determines that the output pulse signal is abnormal when the number of edges of the pulse signal and the number of edges of the monitor signal are different, and the second abnormality determination method uses the level of the pulse signal and the level of the pulse signal. When the levels of the monitor signals do not correspond to each other, it may be determined that the output pulse signal is abnormal.

  Further, in the above-described embodiment, when the pulse signal abnormality detection device is applied to the vehicle control system and the pulse signal of the engine rotation sensor 1 is relayed to another ECU, the TPU 13 as the output unit detects the abnormality of the output pulse signal. The example of detecting the presence or absence has been described. However, the application example of the pulse signal abnormality detection device according to the present invention is not limited to such a case where the pulse signal is relayed. For example, when the ECU outputs a pulse signal whose frequency changes as a drive signal for driving the device to be controlled, whether a normal pulse signal is output as intended or an abnormal pulse signal is output The pulse signal abnormality detection device of the present invention may be applied to detect whether the pulse signal is detected.

Finally, technical features of the above-described embodiment other than those described in the claims are listed.
1. When the pulse edge count value is larger than the monitor edge count value, the first abnormality determination unit (S100 to S140) stops the output of the pulse signal from the output unit (13), and monitors when the pulse signal is stopped. An abnormality mode determination unit (S200 to S260) for determining which of a ground short abnormality and a power short abnormality has occurred based on the signal level.
2. In response to the predetermined restart condition being satisfied, the first abnormality determination unit (S100 to S140) clears the pulse edge count value and the monitor edge count value, and the output unit (13) restarts the output of the pulse signal. .
3. The predetermined restart condition is that the level of the monitor signal has changed while the output of the pulse signal has been stopped, a request to restart the output of the pulse signal has been received from outside, and the output of the pulse signal has been stopped. Either a predetermined time has passed since the start.
4. The second abnormality determining unit (S600 to S650) monitors the level of the pulse signal when the next level change occurs in the pulse signal before a predetermined time (T1) elapses after the level of the pulse signal changes. It is not determined whether or not the signal levels correspond to each other.
5. When the level of the pulse signal does not change, the second abnormality determination unit (S600 to S650) determines whether or not the level of the pulse signal corresponds to the level of the monitor signal every time the predetermined time (T1) elapses. Repeat the judgment.
6. The second abnormality determination unit (S600 to S650) includes a temporary storage unit for temporarily storing a determination result as to whether or not the level of the pulse signal corresponds to the level of the monitor signal. At each T2), the determination result stored in the temporary storage unit is read, an abnormality determination is performed based on the read determination result, and after the determination result is read, the determination result of the temporary storage unit is cleared.
7. When the second abnormality determination unit (S600 to S650) determines that the level of the pulse signal and the level of the monitor signal are incompatible and the level of the monitor signal indicates the Lo level, the temporary storage unit may perform a ground short. The level of the pulse signal and the level of the monitor signal do not correspond to each other in the ground short determination storage unit that temporarily stores the abnormality determination result indicating the abnormality and the second abnormality determination unit (S600 to S650). A power short-circuit determination storage unit that temporarily stores an abnormality determination result indicating a power short-circuit abnormality when the level is determined to indicate a Hi level.
8. The ground short abnormality determination storage unit corresponds to the level of the pulse signal and the level of the monitor signal, and when it is determined that the level of the monitor signal indicates the Hi level, it indicates that no ground short abnormality has occurred. The normality determination result is temporarily stored, and the power supply short-circuit abnormality determination storage unit stores the power supply signal when the level of the pulse signal corresponds to the level of the monitor signal, and the level of the monitor signal is determined to be Lo level. The normal abnormality determination result indicating that no short-circuit abnormality has occurred is temporarily stored, and the second abnormality determination unit (S600 to S650) stores the ground short-circuit abnormality determination storage unit when clearing the determination result of the temporary storage unit. In addition, a value different from the values of the abnormality determination result and the normal determination result is set in the power short-circuit abnormality determination storage unit.

1: engine rotation sensor 10: engine control ECU
11: microcomputer 12: CPU
13: TPU
14: abnormality detection unit 20: transmission control ECU

Claims (5)

An output unit (13) for outputting a pulse signal whose frequency changes,
An abnormality detection unit (14) that performs abnormality detection using a monitor signal that monitors a pulse signal output from the output unit,
The abnormality detection unit,
A first abnormality determination unit (S100 to S100) for performing an abnormality determination based on whether a pulse edge count value for counting the number of edges of the pulse signal and a monitor edge count value for counting the number of edges of the monitor signal match. S140),
A second abnormality determination unit (S600 to S650) for performing an abnormality determination based on whether or not the level of the pulse signal corresponds to the level of the monitor signal;
A pulse signal abnormality detection device in which abnormality determination by the first abnormality determination unit and the second abnormality determination unit is performed in parallel.   The pulse signal abnormality detection device according to claim 1, wherein the abnormality detection unit performs abnormality detection when an abnormality is determined by any of the first abnormality determination unit and the second abnormality determination unit. The output unit outputs the pulse signal whose frequency changes in response to a change in the frequency of the input pulse signal according to an input pulse signal input from the outside,
The first abnormality determination unit uses a value obtained by counting the number of edges of the input pulse signal as the pulse edge count value, and / or the second abnormality determination unit uses the pulse edge level as the level of the pulse signal. 3. The pulse signal abnormality detection device according to claim 1, wherein a level of the input pulse signal is used.   The said 1st abnormality determination part has a count clear part (S270) which clears the said pulse edge count value and the said monitor edge count value, respectively, when the said pulse edge count value is smaller than the said monitor edge count value. 3. The pulse signal abnormality detection device according to any one of 3.   The second abnormality determining unit compares the level of the pulse signal with the level of the monitor signal after a predetermined time has elapsed after the level of the pulse signal has changed, and determines whether both levels correspond to each other. The pulse signal abnormality detection device according to any one of claims 1 to 4, wherein the determination is made.

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