KR20160015909A - Apparatus for Diagnosing In-Vehicle Network - Google Patents

Abstract

An in-vehicle network diagnostics device that enables quick and intuitive diagnosis of communication faults in CAN systems through waveform checking and terminal resistance measurement of signals transmitted through the CAN bus of the vehicle.
The diagnostic apparatus of the present invention is for diagnosing whether or not a communication abnormality occurs in a network in which a plurality of in-vehicle electronic apparatuses are connected to communicate with each other. The diagnostic apparatus may be connected to a connector in the vehicle, which is installed in the vehicle, A communication unit, a measurement unit, and a display unit. The communication unit extracts a communication signal on the network from signals output through the in-vehicle connector. The measuring unit receives the communication signal from the communication unit, performs an oscilloscope signal process so as to display a waveform on the screen with respect to the communication signal, supplies a predetermined voltage to the network through the switching unit, And measures the terminal resistance of the network. The display unit displays the waveform and the termination resistance.
According to the diagnosis apparatus of the present invention, an operator can quickly and intuitively and easily diagnose whether or not a communication abnormality occurs in a CAN system by checking a waveform of a signal transmitted through a CAN bus and measuring a terminal resistance have.

Description

[0001] Apparatus for Diagnosing In-Vehicle Network [

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a vehicle diagnostic apparatus, and more particularly to a diagnostic apparatus by electrical signal detection.

In accordance with the development of electronic control technology, many devices have been electricized in order to improve fuel economy, safety, or convenience in automobiles, and main devices such as engine, transmission, and brake are electronically controlled. Electronic devices mounted on a vehicle such as an engine electronic control unit (ECU), a transmission control unit (TCU), an electronically controlled parking brake EPB, an electronic control suspension (ECS), an anti- , And the communication network is connected to each other through a communication network. Recently, the most attention network is CAN (Controller Area Network).

As shown in FIG. 1, a CAN connects two termination resistors R to two twisted pairs to form a bus, connects each electronic device to a bus in parallel, To-peer network configured to transmit and receive signals in accordance with the standard ISO 11898 defined by the International Organization for Standardization (ISO). Each of the electronic devices connected to the CAN is equipped with a CAN controller and a CAN transceiver for the interface. The voltage levels of the respective bus lines (CAN_H, CAN_L) constituting the CAN bus are complementarily changed, that is, ≪ / RTI > This CAN communication can reduce the number of shipments compared with point-to-point communication methods that connect each electronic device individually, thus making it possible to construct an economical and stable system while reducing wiring cost, complexity and weight. It does.

However, in a CAN system, communication errors may occur for various reasons. For example, a failure may occur in one or more of the CPUs of the electronic devices connected to the CAN, and the CAN bus or the power line may be disconnected or short-circuited. Therefore, if communication error is suspicious, the communication status through the CAN bus must be checked.

One way to check the CAN communication status is to measure the voltage levels of the two bus lines (CAN_H, CAN_L) with an oscilloscope to check that the reverse signal shape matches exactly. However, in order to observe the waveform by the oscilloscope, there is a disadvantage that it is troublesome to disconnect the connector of an electronic device connected to the CAN.

Methods for analyzing the diagnostic device by connecting it to the OBD-II connector provided in the vehicle by means of a DLC cable have also been proposed. For example, Patent Document 1 listed below discloses a PC-based diagnostic apparatus that receives control data transmitted and received by CAN communication through an interface device and inspects the received data frame for diagnosis and analysis. Patent Document 2 discloses a monitoring system for diagnosing a bus off and a time out error due to a failure of a controller in a vehicle control period CAN communication or disconnection and short-circuit of a CAN communication line. Patent Document 3 discloses a data validity diagnostic apparatus capable of judging the validity of data transmitted in a vehicle network.

However, since the devices described in Patent Documents 1 to 3 analyze the hex code data by a large-scale program executed on a PC or a dedicated diagnostic device to determine the validity of the data frame, In addition, there may be difficulties in intuitively and quickly judging the analysis results.

Korean Unexamined Patent Publication No. 2003-0050115 A (Hyundai Motor Company) June 25, 2003 Korean Patent Publication No. KR 10-2009-0063430 A (Hyundai Motor Company) June 18, 2009 Korean Patent Publication No. 10-2010-0029657 A (Hyundai Motor Co., Ltd.) Mar. 17, 2010

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide an in-vehicle network diagnosis apparatus capable of quickly and intuitively diagnosing communication abnormality in a CAN system through a waveform check of a signal transmitted through a CAN bus, And to provide a method of manufacturing the same.

According to an aspect of the present invention, there is provided a diagnostic apparatus for diagnosing communication abnormality in a network in which a plurality of in-vehicle electronic devices are connected to communicate with each other, And includes a communication unit, a measurement unit, and a display unit. The communication unit extracts a communication signal on the network from signals output through the in-vehicle connector. The measuring unit receives the communication signal from the communication unit, performs an oscilloscope signal process so as to display a waveform on the screen with respect to the communication signal, supplies a predetermined voltage to the network through the switching unit, And measures the terminal resistance of the network. The display unit displays the waveform and the termination resistance.

In a preferred embodiment, the diagnostic apparatus further comprises a main control unit for controlling the communication unit, the measurement unit, and the display unit. The communication unit may include a switching control unit that extracts the communication signal from the signals applied to the in-vehicle connector, provides the communication signal to the measurement unit, extracts predetermined information indicating the state of the vehicle, Transmits the control data from the main control unit to the in-vehicle connector, and transmits the vehicle state data output from the in-vehicle connector to the main control unit.

In one embodiment, the diagnostic apparatus includes a main body for housing the communication unit and the display unit; And a measurement pack that houses the measurement unit and can be attached to and detached from the main body. In this case, a jack is provided on either one of the surface of the main body facing the measurement pack and the surface facing the main body of the measurement pack, and the other is provided with a socket, It is preferable to make it possible to tightly contact and tightly contact with each other.

According to the diagnosis apparatus of the present invention, an operator can quickly and intuitively and easily diagnose whether or not a communication abnormality occurs in a CAN system by checking a waveform of a signal transmitted through a CAN bus and measuring a terminal resistance have.

Accordingly, in a situation where there is no problem in the communication state, or when the repair can be made immediately such as disconnection or short-circuit of the wiring, a PC-based diagnostic apparatus or a large-scale dedicated diagnostic system is used to analyze the hex code data, The advantage of this system is that it makes it possible to perform detailed diagnosis by using the PC based diagnosis device in addition to the serious case where the communication condition is defective and the cause of the failure is believed to be caused by the controller failure or unknown. have. Unlike existing large-scale devices that extract and analyze hex code data via OBD-II connector, protocol analysis and data extraction functions are unnecessary and diagnostic work becomes very simple.

The diagnostic device according to the present invention can operate as an oscilloscope or a multimeter. However, unlike a conventional oscilloscope or a multimeter, it is not necessary to take out a probe after removing a connector of an electronic device connected to the CAN, An advantage is that the DLC cable can be connected to the OBD-II connector, so that it can be judged conveniently whether or not a communication error has occurred.

Particularly, according to the preferred embodiment of the present invention, since the diagnostic apparatus is composed of two parts that can be easily attached and detached, there is an advantage that only a part necessary for performing a function to be executed can be separated and used.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the figure,
Figure 1 is a top view of a typical CAN topology;
2 is a block diagram of a diagnostic apparatus according to an embodiment of the present invention;
FIG. 3A is a front view of the product, FIG. 3B is a top view, FIG. 3C is a diagonal view of the upper portion of the product, and FIG.
FIG. 4A is a photograph showing a fastening structure of a main body and a measurement pack in the diagnostic apparatus shown in FIGS. 3A to 3C, FIG. 4A is a photograph of a sash with the main body turned upside down, Strabismus photograph;
5A and 5B are photographs of a product for explaining a method of separating a main body and a measurement pack;
FIG. 6 is a flowchart showing an overall process of a vehicle communication line check function in the diagnostic apparatus of FIG. 2;
7 is a flow chart showing an indicator processing process;
8 is a flowchart showing a waveform display processing process;
9 is a flow chart showing a process of measuring and displaying a terminal resistance;
10 is a screen shot showing an example of an initial screen displayed on an LCD display in the diagnostic apparatus of FIG. 2;
11 is a screen shot showing an example of a pin selection and indicator display screen;
12 is a screen shot showing an example of a waveform display screen; And
13 is a screen shot showing an example of the terminal resistance display screen.

2 shows an embodiment of a diagnostic apparatus according to an embodiment of the present invention. For convenience of explanation, the in-vehicle electronic system 2 is also shown in Fig.

The in-vehicle electronic system 2 includes an engine electronic control unit (ECU), a transmission control unit (TCU), an electronically controlled parking brake (EPB), a non-slip braking device (ABS), an electronically controlled suspension device (ECS) AIRBAG), and each electronic device is connected to each other via first and second bus lines 10 and 20, which are generally denoted as 'CAN_H' and 'CAN_L'. At least two termination resistors R1 and R2 are connected between the first and second bus lines 10 and 20 to form a closed loop and prevent signal reflection. In one embodiment, a shielded twisted pair cable (STP cable) is used for the first and second bus lines 10 and 20 and a cable shield 30 is electrically connected to the vehicle ground 40 Respectively.

An OBD-II connector 90 is provided in the vehicle for enabling the vehicle to be diagnosed and checked by communication with the ECU from the outside. The OBD-II connector 90 includes first and second bus lines 10 , 20 and the cable shield 30 can also be connected. For example, in a vehicle adopting CAN communication based on the ISO15765-4 / SAE J2480 standard, first and second bus lines 10 and 20 are normally connected to pins 6 and 14 of the OBD-II connector 90, respectively Respectively.

The diagnostic apparatus according to the embodiment of the present invention includes a main control unit 110, a communication interface unit 120, a measurement interface unit 130, an LCD display 140, Respectively.

The diagnostic apparatus can be connected to the OBD-II connector 90 of the vehicle through the DLC cable 99, and can perform various diagnostic and inspection functions with respect to the vehicle. For example, the diagnostic apparatus requests a fault code (DTC: Diagnostic Table Code) to the ECU, particularly, the engine-side ECU, receives the fault code data stored in the ECU, and displays the fault code data on the screen so as to confirm the fault of the vehicle. In addition, the diagnostic apparatus can request an operating parameter from the ECU, for example, to check the operating parameters of the vehicle such as the coolant temperature and the air temperature. In addition, the diagnostic apparatus can force a device such as a motor or an injector for testing purposes by applying a forced driving signal to the vehicle. Further, the parameters that the ECU operates can be set, and the operating conditions can be set, for example, after the airbag replacement.

In the present specification including the claims, the data transmitted to the vehicle through the DLC cable 99 and the OBD-II connector 90, for example, fault code request data, operation parameters Request data, forced drive signal data, parameter setting data, and the like will be referred to as "control data ". The data received from the vehicle through the DLC cable 99 and the OBD-II connector 90, such as the fault code data, the operation parameters, and the status data, will be referred to as "status data"

Particularly, according to the present invention, the diagnostic apparatus transmits the CAN signals (CAN_H, CAN_L) transmitted between intra-vehicle devices via the first and second bus lines 10 and 20 of the vehicle to the OBD-II connector 90 DLC cable 99 and determines whether or not the CAN communication is normally operated based on the level of the CAN signal CAN_H and CAN_L and displays it in an indicator manner. The CAN signal waveform and the terminal resistance of the CAN bus are measured, And displayed on the display 140.

2, the main control unit 110 is configured based on a CPU of the apparatus and a program that can be executed by the CPU, and is programmed in accordance with an operator's input through an operation button or a touch panel, 120 and the measurement interface unit 130 are controlled. The main control unit 110 transmits control data to the vehicle via the communication interface unit 120 and receives and interprets status data from the vehicle through the communication interface unit 120 to provide diagnostic information and / Display status information. Particularly, the main control unit 110 receives the CAN communication status determination information, the signal waveform, and the terminal resistance value measured by the measurement interface unit 130, and displays the indicator, the waveform, .

The communication interface unit 120 selects the CAN signal from each pin of the OBD-II connector 90 and transmits it to the measurement interface unit 130 in response to the control signal of the main control unit 110. [ The communication interface unit 120 receives the control data transmitted from the main control unit 110 to the vehicle from the main control unit 110 and transmits the control data to the OBD-II connector 90 through the DLC cable 99, And transmits the vehicle status data received via the OBD-II connector 90 and the DLC cable 99 to the main control unit 110.

In the illustrated embodiment, the communication interface unit 120 includes a switching control unit 122, a vehicle communication circuit unit 124, and a data transfer unit 126.

The switching control unit 122 selects the CAN signal among the respective pin signals of the OBD-II connector 90 which is detected through the DLC cable 99 in response to the control signal of the main control unit 110, . The switching control unit 122 receives the control data from the main control unit 110 via the vehicle communication circuit unit 124 and transfers the control data to the OBD-II connector 90 via the DLC cable 99, 90 and the DLC cable 99 and transmits the detected vehicle state data to the main control unit 110 through the vehicle communication circuit unit 124. [

The vehicle communication circuit unit 124 receives the control data to be transmitted to the vehicle by the main control unit 110 and transmits the control data to the switching control unit 122 so that the switching control unit 122 outputs the control data through the DLC cable 99, And transmits the vehicle state data extracted by the switching control unit 122 to the main control unit 110. [ In the course of data transfer, the vehicle communication circuit 124 may perform signal format changes on the control data and the vehicle status data.

The data transmission unit 126 mediates transmission of signals transmitted and received between the main control unit 110 and the vehicle communication circuit unit 124 and transmits and receives signals between the main control unit 110 and the measurement interface unit 130 Intermediates the transmission of signals.

The measurement interface unit 130 performs measurement for CAN communication check and includes a DLC signal measurement unit 132, an external channel probe connection unit 134, a channel signal measurement unit 136, a signal processing unit 138).

The DLC signal measuring unit 132 measures the CAN bus signals of the OBD-II connector 90 detected by the switching control unit 122, that is, the first and second bus lines 10 and 20, that is, the CAN signals CAN_H and CAN_L And transmits it to the signal processing unit 134. [

The external channel probe connection portion 136 includes a plurality of probe connection ports installed on the surface of the diagnostic device. When an operator disconnects one of the electronic devices connected to the CAN bus line while one end of the probe is connected Allowing you to manually measure the CAN signal level. The channel signal measurement unit 138 transmits a probe measurement signal output from the external channel probe connection unit 136 to the signal processing unit 134.

The signal processing unit 134 performs a signal normal determination process for displaying whether the signal is normal or not in the indicator manner for the CAN signals CAN_H and CAN_L received through the DLC signal measurement unit 132, To perform the oscilloscope signal processing for displaying the CAN signal (CAN_H, CAN_L) in an oscilloscope manner, the terminal resistance of the CAN bus of the vehicle is measured. Also, the signal processor 134 may perform the above-described functions on the signal manually measured by the channel signal measuring unit 138 through the external channel probe connection unit 136. [ The signal processing unit 134 provides the main control unit 110 with identification information on the signal status, waveform data, and measured terminal resistance values through the data transfer unit 126 of the communication interface unit 120 .

FIG. 3A is a front view of the product, FIG. 3B is a photograph of an upper surface, and FIG. 3C is a photograph of a sash as viewed from an upper part of the upper part of the product .

In the illustrated embodiment, the diagnostic device is comprised of two parts, a main body 200 and a measurement pack 250, and the measurement pack 250 is selectively attached to and detached from the back surface of the main body 200 It is possible to do. 2, the main body 200 includes a main control unit 110 and a communication interface unit 120. An LCD display 140 and a plurality of function selection buttons are provided on the front side A cable connection portion 210 for connecting the DLC cable 99 to the upper surface, and a USB port 212 for connecting a portable small printer and a USB device, for example. On the other hand, in the measurement pack 250, the measurement interface unit 130 is installed in the functional block shown in FIG. 2, and the external channel probe connection part 136 including a plurality of probe connection ports is provided on the upper surface. On the left and right sides of the bottom surface of the measurement pack 250, locking levers 260 and 270 used for separating from the main body 200 are provided.

The measurement pack 250 is an optional device added for the CAN communication check, and the main body 200 can operate independently without the measurement pack 250. That is, even when the measuring pack 250 is not attached to the main body 200, the main body 200 can be used to perform various functions such as diagnosis of a failure code, confirmation of operation parameters of a vehicle, actuation through application of a forced driving signal, sensor simulation, Signal interface device.

4A is a photograph showing the fastening structure of the main body 200 and the measurement pack 250 in the diagnostic apparatus shown in Figs. 3A to 3C, Fig. 4A is a photograph of a sash with the main body 200 turned upside down, And 4b is a photograph of a sash viewing the measurement pack 250 from the upper side.

Hooks 262 and 264 integrally formed in the locking lever 260 are provided on the left side of the measuring pack 250 facing the main body 200. Similarly to the locking lever 270, Hooks 272 and 274 integrated in the recess are provided in the recess. A connector 282 is provided on the front face of the measurement pack 250 facing the main body 200 to electrically connect the main body 200 to the main body 200 to transmit and receive signals and to receive electricity from the main body 200. In the illustrated embodiment, connector 282 is in the form of a female jack. In addition, a groove 284 is formed on the front surface of the measurement pack 250 to facilitate alignment when fastened to the main body 200.

On the other hand, on the left side of the back face of the main body 200 facing the measuring pack 250, engaging portions 222 and 224 which can be engaged with the hooks 262 and 264 of the measuring pack 250 are formed And fastening portions 232 and 234 which can be fastened to the hooks 272 and 274 of the measurement pack 250 are formed on the right side. A connector 242 is provided on the back surface of the main body 200 so as to be able to transmit and receive signals to and from the measurement pack 250 by being fastened to the connector 282 of the measurement pack 250. In the illustrated embodiment, the connector 242 of the body is in the form of a male jack. A protrusion 244 corresponding to the groove 284 of the measurement pack 250 is formed on the back surface of the main body 200.

The main body 200 and the measurement pack 250 are fastened or separated as follows.

The recesses 284 of the measurement pack 250 are first aligned with the protrusions 244 of the main body 200 and the protrusions 244 of the measurement pack 250 are aligned with the protrusions 244 of the main body 200. [ Aligns the connector 282 with the connector 232 of the main body 200. When the measurement pack 250 is pressed on the main body 200, the hooks 262, 264, 272, and 274 of the measurement pack 250 are engaged with the engagement portions 222, 224, 232, and 234 of the main body 200, respectively. As shown in Fig. As a result, the main body 200 and the measurement pack 250 are integrated and can be transported and used as a single device.

Here, the pin of the main body side connector 242 in the form of a male jack is inserted into the measurement pack side connector 282 in the form of a female jack, and the rim of the main body side connector 242 is inserted into the measurement The connectors 242 and 282 do not form any gap between the main body 200 and the measurement pack 250 because the main body 200 is inserted into the recess formed around the pack side connector 282, 200 and the measurement pack 250 can maintain the surface contact state.

In the case where the measurement pack 250 is to be separated by the main body 200, in a state in which the locking button of the locking levers 260 and 270 on the right and left sides of the measurement pack 250 is pressed after the diagnosis device is turned upside down, The locking levers 260 and 270 are pivoted to the left and right. At this time, the engagement of the hooks 262, 264, 272, and 274 of the measurement pack 250 and the engagement portions 222, 224, 232, and 234 of the main body 200 is released, 262, 264, 272, and 274 push the back surface of the main body 200 to cause a clearance between the back surface of the main body 200 and the front surface of the measurement pack 250. 5B, the connection between the connector 282 of the measurement pack 250 and the connector 232 of the main body 200 is released and the measurement pack 250 is disconnected from the main body 200. Then, (250) is separated from the main body (200).

As described above, according to the present embodiment, the measurement pack 250 can be easily mounted on the main body 200, fastened, and separated. Therefore, the measurement pack 250 can be quickly mounted as an optional device to the main body 200, which can be used independently as a signal interface device, and can be used or separated.

FIG. 6 shows the overall process of the process of performing the vehicle communication line check function in the diagnostic apparatus of FIG.

2 is first turned on and the 'Utility' menu is selected, a communication line check initial screen as shown in FIG. 10 is displayed on the LCD display 10. When the user selects the 'vehicle communication line check' function in the initial screen of FIG. 10, the pin selection and indicator display screen as shown in FIG. 11 is displayed on the LCD display 10. On the left side of the screen of Fig. 11, information on pins detected by the current CAN signals CAN_H and CAN_L is displayed on the OBD-II connector 90, and whether or not the CAN signals CAN_H and CAN_L are normal is displayed on the right side of the screen do.

11, the user confirms the pin information of the CAN bus line to be measured among the pins of the OBD-II connector 90, and can change it as necessary (operation 300). That is, in a vehicle adopting CAN communication based on the ISO15765-4 / SAE J2480 standard, the first and second bus lines 10 and 20 are normally connected to pins 6 and 14 of the OBD-II connector 90, respectively So that pins 6 and 14 are displayed on the left side of the screen of Fig. 11 as initial states. However, for vehicles with different pin assignments, the user can change the pin number after selecting the connector image for each CAN signal (CAN_H, CAN_L) pin.

Then, the user connects the DCL cable 99 of the diagnostic apparatus to the OBD-II connector 90 of the vehicle (step 302). Here, step 302 may be performed before step 300.

The diagnostic device is turned on and the DCL cable 99 is connected to the OBD-II connector 90 of the vehicle. In the right side of the screen of FIG. 11, whether or not the CAN signal CAN_H, CAN_L is normal is displayed in an indicator manner. If the waveform of the high CAN signal CAN_H is normal, the two indicators on the upper right side of the screen of FIG. 11 alternately flash with a certain period, for example, a period of 2 seconds. Likewise, if the waveform of the low CAN signal CAN_L is normal, the two indicators on the lower right side of the screen of Fig. 11 alternately flicker under the same cycle as above. Accordingly, the user can check whether the waveform of the communication line is normal or not by checking the indicator (operation 304).

If it is determined that an additional check is required after the indicator check, the user selects a 'waveform check' function button provided at the bottom of the screen of FIG. 11 to perform a waveform check function (steps 306 and 308) The terminal resistance measurement function can be performed by selecting the 'terminal resistance check' function button (operation 310 and 312).

7 shows an indicator processing process for indicating the indicator of the communication line status.

When the DLC signal measurement unit 132 of the measurement interface unit 130 measures the waveforms of the CAN signals CAN_H and CAN_L in step 320, the signal processing unit 138 calculates a predetermined threshold value for each of the measured waveforms high " and " low " levels of the signal based on the threshold level (Step 322). Then, the signal processing unit 138 determines whether the state in which the 'high' and the 'low' levels can be clearly distinguished for each of the CAN signals CAN_H and CAN_L (operation 324). The signal processing unit 138 outputs status information indicating that the signal is normal to the data transfer unit 126. The data transfer unit 126 transfers status information indicating that the signal is normal to the CAN signal CAN_H, To the main control unit 110, and the main control unit 110 performs an indicator blinking process at a level that can be perceived by the user (operation 326). On the other hand, when a state in which 'high' and 'low' levels can not be clearly distinguished for each of the CAN signals CAN_H and CAN_L occurs, the signal processing unit 138 transmits state information indicating that the signal is abnormal to the data transfer unit 126 To the main control unit 110, and the main control unit 110 does not perform the indicator blinking process (operation 328).

Fig. 8 shows a waveform display processing process for displaying the CAN signal (CAN_H, CAN_L) in an oscilloscope manner for waveform check.

The signal processing unit 138 receives the CAN signals CAN_H and CAN_L through the DLC signal measuring unit 132 of the measurement interface unit 130 And the waveform is scaled in the vertical direction according to the set range (operation 342). Then, the signal processing unit 138 optimizes the time axis in accordance with the output speeds of the CAN signals CAN_H and CAN_L, and sets the width and the scaling step of the time period (Step 344). In step 346, the signal processing unit 138 performs a data triggering function in response to the instruction of the main control unit 110 in response to the user's trigger point designation. In the present specification including the claims, 'oscilloscope signal processing' refers to a process for scaling a range and a time axis of a signal waveform as described above.

The signal processing unit 138 transmits the waveform data of the CAN signals CAN_H and CAN_L to the main control unit 110 according to the time base information scaled in the vertical direction and optimized in the horizontal direction, Data is displayed on the LCD display 140 in the format shown in FIG. 12, for example (operation 348). Here, the main control unit 110 may store the waveform data in a memory and provide a viewing function.

In the process of performing such a waveform display processing process, the diagnostic apparatus of the present invention operates as if it were an oscilloscope.

9 shows a process of measuring and displaying a terminal resistance.

When the user selects the 'terminal resistance check' function button on the screen of FIG. 11, the diagnostic apparatus checks whether the ignition switch of the vehicle, that is, the ignition key is in OFF state, before measuring the terminal resistance. For example, the signal processing unit 138 can check whether the ignition key is turned off by checking the first and second bus lines 10 and 20 through the DCL cable 99 and the OBD-II connector 90. [ If the ignition key of the vehicle is not turned off (operation 360), the main control unit 110 outputs error information including the guidance message through the LCD display 140 (operation 362).

In step 364, the signal processing unit 138 applies a constant voltage to the first and second bus lines 10 and 20 through the DLC signal measuring unit 132, the DCL cable 99 and the OBD-II connector 90 At this time, the current flowing through the first and second bus lines 10 and 20 is measured, and then the termination resistance is calculated based on the applied voltage and the measured current. The calculated terminal resistance value is provided to the main control unit 110 via the data transfer unit 126. [

The measurement of the termination resistance can be repeated in real time, and the main control unit 110 accumulates the terminal resistance values repeatedly measured to calculate the maximum value / minimum value / average value, And displays it on the LCD display 140 (operation 366).

In the process of performing such a terminal resistance measurement and display process, the diagnostic apparatus of the present invention operates like an automatic multimeter.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

For example, in the above-described embodiment, the measurement pack 220 is separately provided in the main body 200, but the measurement pack 220 is separately provided in the main body 200 The main control unit 110, the communication interface unit 120, the measurement interface unit 130, and the LCD display 140 may be integrally formed.

Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

2: In-vehicle electronic system
10: first bus line, 20: second bus line
90: OBD-II connector, 99: DLC cable
110: Main control unit
120: Communication interface unit
130: Measurement interface unit
140: LCD display
200:
210: cable connection, 212: USB port
260, 270: locking lever, 262, 264, 272, 274: hook
282: connector, 284: groove
222, 224, 232, 234:
242: connector, 244:

Claims (4)

An in-vehicle network diagnostic device installed in the vehicle and capable of being connected via a cable to an in-vehicle connector connected to the network, for diagnosing whether a plurality of in-vehicle electronic devices are connected and diagnosing communication abnormality in a network communicating with each other ,
A communication unit for extracting a communication signal on the network from signals output through the in-vehicle connector;
An oscilloscope signal processing is performed so as to receive the communication signal from the communication unit and a waveform for the communication signal can be displayed on the screen, a predetermined voltage is supplied to the network through the switching unit, A measurement unit for measuring a termination resistance of the network; And
A display unit for displaying the waveform and the termination resistance;
The network diagnostic apparatus comprising: The method according to claim 1,
A main control unit for controlling the communication unit, the measurement unit, and the display unit;
Further,
The communication unit
Extracts the communication signal from the signals applied to the in-vehicle connector and provides the communication signal to the measurement unit, extracts predetermined information indicating the state of the vehicle and provides the extracted information to the main control unit, A switching control unit for transmitting the vehicle state data output from the in-vehicle connector to the in-vehicle connector, and for transmitting the vehicle state data to the main control unit;
The network diagnostic apparatus comprising: The method according to claim 1,
A main body housing the communication unit and the display unit; And
A measuring pack which accommodates the measuring unit and can be attached to and detached from the main body;
The network diagnostic apparatus comprising: The method of claim 3,
Wherein a jack is provided on one of a surface of the main body facing the measurement pack and a surface of the measurement pack facing the main body, and a socket is provided on the other main body and the measurement pack, A network diagnostic device in the vehicle.

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