JPH04132340A - Multiplex transmission system - Google Patents

Abstract

PURPOSE:To easily discriminate the fault of a multiplex unit main body and the disconnection fault of a branch line interconnecting a multiplex unit and a bus line by closing a switch means for a prescribed time after each timer time of each multiplex unit and detecting the presence of a voltage between a signal line and ground for this period. CONSTITUTION:A current flows to a diode by changing the polarity of a power supply voltage applied to a power line 1b, a timer means starts its operation and a switch means is closed for a prescribed time after a time set to the timer. A signal line 1a and a ground line 12c are connected for this period, a voltage is applied during that time and the voltage is detected by a voltage detection means. The operation is implemented by each of multiplex units An-Hn for each time set to the timer. Thus, whether a fault exists in the multiplex unit main bodies An-Hn or a disconnection exists in branch lines 12a, 12b interconnecting the multiplex units An-Hn and the bus line 1 is easily discriminated.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a multiplex transmission system installed mainly in automobiles, etc., and is particularly concerned with failures in the main body of the multiplex unit and branch connections connecting the multiplex unit and bus lines. The present invention relates to a multiplex transmission system that can easily determine whether a line is disconnected or not.

"Prior Art" As a type of bus applied to multiplex transmission systems, a multi-drop ring in which both ends of a multi-drop bus are short-circuited has been developed by the applicant (Japanese Patent Application No. 63-1).
49346).

This multi-drop ring (hereinafter referred to as a bus line) is made of a single wire, a pair of wires, a twisted pair of wires, a Nord wire, a coaxial cable, or the like.

FIG. 6 is a schematic configuration diagram showing a multiplex transmission system for automobiles using this bus line. It is assumed that the bus line 1 consists of a signal line and a power supply line (not shown). In this figure, multiplex units A-G are connected to bus line l, respectively. These multiple units A
-G controls various devices such as lamps, wipers, and washers, and receives switch signals from various devices, and each unit communicates with other multiplex units and messages as shown in the schematic configuration diagram in Figure 7. Communication section 2 for sending and receiving
and a control section 3 that controls the communication section 2 and various devices (not shown).

In such a configuration, each of the multiplex units A to G sends and receives messages to and from each other via the bus line 1 to control various devices. For example, if a stop lamp switch is connected to multiplex unit 8 and a stop lamp is connected to multiplex unit D, when the driver depresses the brake pedal, multiplex unit 8 sends a switch signal to turn on the stop lamp. The containing message is sent to multiplexing unit D via multidrop ring l. The multiplex unit D reads the sent message and supplies power to the stop lamp based on the switch signal included in the message, lighting the stop lamp.

``Problems to be Solved by the Invention'' By the way, in the conventional multiplex transmission system described above, when a multiplex unit does not respond, it is assumed that the multiplex unit itself is malfunctioning, or that the multiplex unit and the bus line In order to determine whether the branch lines (signal branch line, power supply branch line, and ground line) connecting the lines were broken, the branch lines were pulled out and inspected. However, since this inspection requires a large number of man-hours, there is a problem in that maintainability is very poor.

This invention has been made in view of the above-mentioned circumstances, and is a multiplex transmission system that can easily distinguish between a failure of the multiplex unit i/main unit and a disconnection of a branch line connecting the multiplex unit, soto, and the bus line. is intended to provide.

"Means for Solving the Problem" A multiplex transmission system according to claim 1 includes: a bus line having a signal line and a power supply line; a plurality of multiplex units connected to the bus line for controlling various devices; In a multiplex transmission system comprising a battery that supplies a power supply voltage between a ground and the power supply line, a power supply voltage having a polarity opposite to that of the battery is supplied between the power supply line and the ground line instead of the battery. A voltage supply means, a voltage detection means inserted between the signal line and the power supply line, and a plurality of power supply branch lines connecting each multiplex unit and the power supply line inside the unit and each of the power supply lines. A diode that is inserted between the inside of the unit and a ground line that connects the multiplex unit and the ground and becomes conductive when the voltage supply means is used, and a diode that is connected in series to the group unit of each multiplex unit. and a timer means for setting a different timer time for each multiplex unit, and an intermediary between the inside of the unit of the signal branch line connecting between each multiplex unit and the signal line and the inside of the unit of the ground line. The multiplex transmission system according to claim 2, further comprising a switch means which is inserted into the device and becomes closed for a predetermined period after the timer time of the timer means, the multiplex transmission system according to claim 2, The multiplex transmission system according to claim 3, characterized in that a diode is inserted, comprises a bus line having a signal line and a power supply line, and a plurality of multiplex units connected to this bus line and controlling various devices. , a battery that supplies a Ti source voltage between the ground and the 011 power supply line, nj
Voltage changing means capable of setting the value of the power supply voltage supplied between the power supply line and the ground to be higher than that in normal use; voltage detection means inserted between the signal line and the power supply line; Interposed between the inside of the unit of the power supply branch line connecting between each multiplex unit and the power line described above, and the inside of the unit of the ground line connecting between each multiplex unit described in 01j and the ground described in n;j. a constant voltage diode which becomes conductive when a higher N source voltage is set by the voltage changing means n11, and a constant voltage diode connected in series to the constant voltage guide of each multiplex unit,
a timer means for setting a different timer time for each multiplex unit;
5. The multiplex transmission system according to claim 4, further comprising a switch means which is inserted between the ground line and the inside of the unit and is closed for a predetermined period after the timer time of the timer means. The present invention is characterized in that a light emitting diode is inserted in series with the constant voltage guide according to claim 3.

"Function" According to the configuration described in claim 1, by changing the polarity of the power supply voltage supplied to the power supply line, current flows through the diode and the timer means starts operating. After the timer has elapsed, the switch means is closed for a predetermined period of time. During this period, the signal line and the ground line are in a conductive state, and a voltage +II+ is applied between them. This voltage is detected by a voltage detection means.

Such operations are performed in each multiplexing unit every timer period. In this case, if a voltage is detected, it can be determined that there is no disconnection in the signal branch line, power supply branch line, and ground line. In this case, if there is no disconnection in each branch line of a multiplex unit and the multiplex unit is unable to send or receive signals to or from all other multiplex units, the multiplex unit itself is malfunctioning. Kotowa is strong. On the other hand, if no voltage is detected by the voltage detection means, it can be seen that there is a disconnection in at least one of the signal branch line, the 7Ii Kj branch line, and the ground line.

Therefore, it is possible to easily determine whether there is a failure in the main body of the multiplex unit or whether there is a break in the 4-way branch line connecting the multiplex unit and the bus line.

According to claim 2, by inserting a light emitting diode 1 in series with the diode according to claim 1, it is possible to determine whether the power supply branch line or the ground line is disconnected or the signal branch line is disconnected. can do.

According to the third aspect of the present invention, by setting the value of the power supply voltage supplied to the power supply line to a value higher than that during normal use, current flows through the constant voltage diode and the timer means starts operating. After the timer has elapsed, the switch means is closed for a predetermined period of time. During this period, the signal line and the ground line are in a conductive state, and a voltage is applied between them. This voltage is detected by the voltage detection means. The above operation is performed in each multiplexing unit every timer period. Hereinafter, similarly to the case described in claim 2 above, it is possible to easily distinguish between a failure in the multiplex unit main body and a break in the branch line connecting the multiplex unit and the bus line.

Further, according to claim 4, by inserting a light emitting diode in series with the constant voltage diode according to claim 3, disconnection of the power supply branch line or the ground line can be prevented as in the case of claim 2. It can be determined whether the signal branch line is disconnected or the signal branch line is disconnected.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a multiplex transmission system as an embodiment of the present invention. In this figure, bus line l
The female connector 5 is connected to the signal line la via the line 4.
is connected to the power line t of the bus line l.
A female connector 7 is connected to b via a line 6. A male connector 8 is connected to this female connector 7, and a battery 9 is connected between this male connector 8 and the ground.
is inserted.

Each multiplex unit An-En is different from conventional multiplex units 8 to 8.
In addition to the function of E, each branch line (signal branch line! 2a,
It has a function of detecting disconnection of the m source branch line 12b and ground line +2c). FIG. 2 is a circuit diagram showing a specific example of the function. Note that this circuit diagram shows a multiplex unit An.

In this figure, the signal branch line 12a and the ground line +
A series connection circuit of the contact 13a+ of the timer 13 and the contact 14a of the timer 14 is inserted between the internal side of the multiplex unit An of 2c, and the power supply branch line 12b and the ground line +2c of the internal side of the multiplex unit An. Timer 14 in between
A series connection circuit of the coil portion 14b, the contact 13at of the timer 13, and the diode 15 is inserted. Further, the coil portion 13b of the timer 13 is inserted in parallel to the series circuit of the coil portion 14b of the timer 14 and the contact +3at of the timer 13. Each of the contacts 13a+ and 13a* of the timer 13 and the contact 14a of the timer 14 is a normally open contact (normal oven). In this case, the timer 13 closes its contacts 13a+ and 13a after the timer setting time (=T,)
t is in the closed state, and the timer 14 is set for the timer setting time (-d,
) After that, the contact 14a is opened. FIG. 3(b) is a time chart showing this state. Note that the other multiplex units Bn-En also perform the same operations as the multiplex unit An. However, as shown in the time chart of FIG. 4(C), the timer setting time T,' of multiplex unit Bn is longer than that of multiplex unit An, and other multiplex units C
The timer setting time for n=En is also set to become longer as the time progresses.

That is, T+<T+'<T+...
···It has become.

In FIG. 2, the cathode of the diode 15 described above is connected to the power supply branch line 12b. Also,
A diode 1 is connected to this power supply branch line 12b inside the unit from the point where the cathode of the diode 15 is connected.
6 are inserted in series. This diode 16 is for protecting the internal circuit of the unit. The above-mentioned relays 13, 14 and diodes +5, 16 constitute an internal fault diagnosis unit 17.

Next, FIG. 4 is a block diagram showing the electrical configuration of the external failure diagnosis unit 20 used for failure diagnosis. This fault diagnosis unit 20 supplies a reverse voltage to the mD line lb of the bus line 1.

In this figure, 21 and 22 are male connectors, which can be connected to the female connector 7.5. The male connector 2I is connected to the negative electrode of the battery 24 via the switch 23, and the male connector 22 is connected to the voltmeter 25.
It is connected to the negative electrode of the battery 24 via.

Next, a fault diagnosis method using the above-mentioned internal fault diagnosis unit 17 and external fault diagnosis unit 20 will be explained.

Although it is necessary to diagnose whether or not there is a disconnection in the bus line 1 before performing the failure diagnosis by each of the failure diagnosis units 17 and 20, the discussion here will proceed assuming that there is no disconnection in the bus line 1.

First, remove the male connector 8 from the female connector 7 and remove the battery 9. Next, the male connector 21 of the external failure diagnosis unit 20 is connected to the female connector 7. Further, the male connector 22 of the failure diagnosis unit 20 is connected to the female connector 5.

In this case, it is assumed that the switch 23 of the external failure diagnosis unit 20 is in an open state.

After the above settings are completed, switch 23 is closed. As a result, a reverse voltage is supplied to each multiplex unit An to En, and a forward current flows through the diode 15 of each internal failure diagnosis unit 17, causing the timer 13 to operate. After a period T after the timer 13 starts operating, the contacts 13a+ and 13at of the timer 13 of the multiplex unit An are closed. As a result, the timer 14 starts operating, and its contact 14a becomes open after a period T. That is,
The contact 14a remains open for a period T. Since the signal branch line 12a is grounded during the period T during which the contact 14a is closed, the voltmeter 25 indicates the power supply voltage of the battery 24. In this case, if the voltmeter 25 indicates the power supply voltage of the battery 24, the signal branch line 12a, the disconnection branch line 121)
Also, it can be seen from the internal failure diagnosis unit 17 of the ground line 12c that there is no disconnection in the part on the bus line l side.

If there is no disconnection in each branch line 12a-+2c, and multiplex unit An cannot exchange mesocenes with all of the other multiplex units Bn-En, this multiplex unit An has failed. I know that there is.

When the operation of the timer 13.14 of the internal fault diagnosis unit 17 of the multiplex unit An ends in this way, the operation of the timer 13.14 of the multiplex unit Bn starts, and the same fault diagnosis as in the case of the multiplex unit An is performed. will be carried out. Thereafter, failure diagnosis is sequentially performed for the multiplex unit cn=En in the same manner.

Next, FIG. 5 is a circuit diagram showing an application example of the internal fault diagnosis unit 17 and the external fault diagnosis unit 20 described above. The internal failure diagnosis unit 26 has a resistor 27 inserted at both ends of the coil section 13b of the timer 13, a power supply branch line +2b, the resistor 27, and the coil section 1 of the timer 14.
4b and the common connection end of the contact t3ay of the timer 14, a series connection circuit of a resistor 28 and a constant voltage diode 29 is inserted in the internal failure diagnosis unit 1 described above.
This is different from 7. Further, as the constant voltage diode 29, one whose breakdown voltage is lower than the combined voltage value of the batteries 31 and 32 of the external failure diagnosis unit 30 is used. The external failure diagnosis unit 30
The combined voltage of 1.32 and the voltage of the battery 32 can be selectively selected by a switch 33. The voltmeter 25 has one end connected to the male connector 22 and the other end connected to the positive electrode of the battery 32. Note that the other end of the voltmeter 25 may be connected to the positive electrode of the battery 31.

Next, the operation of each of the diagnostic units 26 and 30 will be explained. Here, the power supply voltage of batteries 31 and 32 is set to 7V.
, 5V, and the breakdown voltage of the constant voltage diode 29 is IOV.
shall be. Furthermore, since the operations of the timers 13 and 14 in the internal failure diagnosis unit 26 are similar to those in the internal failure diagnosis unit 17, the time chart shown in FIG. 3 can be used as is.

Now, from the side that contacts the middle point C of the switch 33 to the contact A side, the power supply voltage of 12V is applied to each multiplex unit An.
-En is supplied to the internal failure diagnosis unit 26, current flows through each constant voltage diode 29, and the timer 13 operates. After the period 'r1, the contacts 13a+ and 13at of the timer 13 of the multiplex unit An are closed. As a result, the timer 14 starts operating, and its contact 14a becomes open after a period T. That is, the contact 14a is in the closed state during the period T. During the period 1 when this contact 14a is in the closed state, the signal branch line 12
Since a is grounded, the voltmeter 25 indicates the power supply voltage of the battery 32. In this case, voltmeter 2
5 indicates the power supply voltage of the battery 32, the internal fault diagnosis unit 17 of the signal branch line 12a, power supply branch line +2b and ground line 12c indicates the bus line l.
It can be seen that there is no disconnection in the side part. If there is no disconnection in each branch line, and the multiplex unit An is only able to send and receive messages to and from all of the other multiplex units )-Bn-En, it can be determined that this multiplex unit An is out of order. .

In this way, timer 13.14 of multiplex unit An
When the operation of Bn is completed, the timers 13 and 14 of the multiplex unit I3n operate in the same manner as in the case of the multiplex unit 80, and a failure in this multiplex unit Bn is diagnosed. Thereafter, failure diagnosis is sequentially performed for the multiple unit hcn-En in the same manner.

In addition, in the two-legged embodiment, the internal failure diagnosis unit 1
By inserting a light emitting diode in series with the diode 15 of 7, the power supply branch line +2b or the ground line +
2c or the signal branch line 12a can be determined. Similarly, in the internal failure diagnosis unit 26, a similar determination can be made by inserting a light emitting diode in series with the constant voltage diode 294.

Further, in the embodiment described in "-", the timer 14 was inserted between the signal branch line 12a and the ground line 12c, but
In place of this timer 14, a pulse generating circuit such as a one-way yacht circuit may be used.

Furthermore, it goes without saying that the above embodiments can be applied to any vehicle that employs a multiplex transmission system, in addition to automobiles.

"Effects of the Invention" As explained above, the multiplex transmission system of the present invention provides the following effects.

According to the multiplex transmission system according to claim 1, by changing the polarity of the Ti edge voltage supplied to the power supply line, the timer means of each multiplex unit is operated in sequence, and the switch means is closed for a predetermined time after each timer time. Since the presence or absence of voltage between the signal line and the ground is detected during this period, failures in the multiplex unit itself and disconnections in branch lines connecting the multiplex unit and the bus line can be easily detected. can be determined. Therefore, since these can be easily determined, there is no need to extend the branch bus line and inspect it in the event of a failure. As a result, the number of man-hours is reduced compared to before.
Improves maintainability.

According to the multiplex transmission system according to claim 2, claim 1
By inserting a light emitting diode in series with the diode ζ described in 1., it is possible to determine whether the power supply branch line or the ground line is disconnected or the signal branch line is disconnected.

According to the multiplex transmission system according to claim 3, by setting the value of the bell voltage supplied to the power line to a higher value than in normal use, the timer means of each multiplex unit is operated in sequence, and each timer Since the switch means is kept closed for a predetermined period of time and whether or not the voltage between the signal line and the ground is detected is detected during this period, the same effect as in claim 1 can be obtained.

According to the multiplex transmission system according to claim 4, claim 3
By inserting a light emitting diode in series with the constant voltage diode according to the invention, the same effect as in the case of claim 2 can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a multiplex transmission system according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing an internal fault diagnosis unit 17 constituting the embodiment, and FIG. 3 is a circuit diagram showing the same fault diagnosis unit 17. FIG. 4 is a time chart for explaining the operation of the external failure diagnosis unit 20 constituting the above embodiment.
FIG. 5 is a circuit diagram showing the internal failure diagnosis unit +7.
FIG. 6 and FIG. 7 are schematic configuration diagrams showing a conventional multiplex transmission system. 1. Bus line, 1a...signal line, 1b...T
JSK+ line, 5.7...Female connector, 9...
...Battery, 12a...Signal branch line, +
2b...Power supply terminal, 12c...Ground line, 13. Timer (timer means), 14...Timer (switch means), 15.
Diode (13 to 16 are internal failure diagnosis units), 17 is horizontally removed), 21.22... - male connector, 23... switch, 24... battery, 25 voltmeter (21 to 25 are voltage detection) 27. 28...Resistor, 2... Constant voltage diodes (13, 1427 to 29 constitute the internal fault diagnosis unit 26), 31. 32...Battery, 33...
- Switches (2122, 2531 to 33 constitute the external failure diagnosis unit 30 which is a voltage detection means), Δn-En...
・Multiple units.

Claims (4)

[Claims] (1) A bus line having a signal line and a power supply line, a plurality of multiplex units connected to this bus line to control various devices, and a battery that supplies a power supply voltage between the ground and the power supply line. In the multiplex transmission system comprising: voltage supply means for supplying a power supply voltage of opposite polarity to the battery between the power supply line and the ground line instead of the battery; and a voltage supply means inserted between the signal line and the power supply line. between the voltage detecting means connected between the multiplex units and the power supply line, and the inside of the unit of a plurality of power branch lines connecting each of the multiplex units and the power supply line, and the inside of the unit of a ground line that connects between each of the multiplex units and the ground. a diode that is inserted into the voltage supply means and becomes conductive when the voltage supply means is used; a timer means that is connected in series with the diode of each of the multiplex units and has a different timer time set for each multiplex unit; switch means inserted between the inside of the unit of a signal branch line that connects the unit and the signal line and the inside of the unit of the ground line and closed for a predetermined period after the timer time of the timer means; A multiplex transmission system characterized by: (2) The multiplex transmission system according to claim 1, characterized in that a light emitting diode is inserted in series with the diode. (3) A bus line having a signal line and a power line, a plurality of multiplex units connected to this bus line to control various devices, and a battery that supplies a power supply voltage between the ground and the power line. In the multiplex transmission system comprising: a voltage changing means that can set the value of the power supply voltage supplied between the power supply line and the ground to be higher than in normal use; and a voltage changing means inserted between the signal line and the power supply line. an intervening device between the voltage detecting means, the inside of the unit of a power branch line that connects each of the multiplex units and the power line, and the inside of the unit of a ground line that connects between each of the multiplex units and the ground. a constant voltage diode which is connected in series to the constant voltage diode of each of the multiplex units and sets a different timer time for each multiplex unit; and a timer means inserted between the inside of the signal branch line connecting each of the multiplex units and the signal line and the inside of the ground line of each of the multiplex units. 1. A multiplex transmission system comprising: switch means that is closed for a predetermined period after a timer time. (4) The multiplex transmission system according to claim 3, characterized in that a light emitting diode is inserted in series with the constant voltage diode.