JPH1041965A - Vehicle-use multiplex communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the vehicle use multiplex communication equipment to prevent deterioration in the reliability of the system due to a fault of a multiplex communication input or/and output circuits or the like. SOLUTION: A standby multiplex communication output circuit 6f and a standby multiplex communication input circuit 6g in parallel with a multiplex communication output circuit 6c and a multiplex communication input circuit 6d are connected to a standby multiplex communication output terminal T×2 and a standby multiplex communication input terminal R×2 of a CPU 6b in common use for a transmission line state discrimination means. The multiplex communication output circuit 6c and the multiplex communication input circuit 6d are connected to a transmission line 5 via a contact A of a changeover means 6h. The standby multiplex communication output circuit 6f and the standby multiplex communication input circuit 6g are connected to the transmission line 5 via a contact B of the changeover means 6h. An output port P0 of the CPU 6b is connected to a drive circuit 6i controlling the contact changeover of the changeover means 6h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex communication device for a vehicle for multiplexing signals through a transmission line, and to a device for preventing a decrease in system reliability due to a failure of a multiplex communication input or / and output circuit. .

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open Nos.
The conventional multiplex communication transmitting unit 1 disclosed in Japanese Patent No. 276564 and shown in FIG.
z on / off information through the input circuit 1a and the CPU 1
Detect at b. The CPU 1b transmits ON / OFF information of the switches 4a to 4z in a time division manner from the multiplex communication output terminal Tx, and outputs the information to the transmission line 5 via the multiplex communication output circuit 1c. The switch 4 output to the transmission line 5 in a time-division manner
The multiplex communication receiving unit 2 or the receiving unit 3 receives the on / off information of a to 4z. The multiplex communication receiving unit 2 or the multiplex communication receiving unit 3 displays on the display 2d or the display 3d based on the received ON / OFF information of the switches 4a to 4z. 2b, 3
b denotes a CPU having multiplex communication input terminals Rx for receiving signals from the multiplex communication input circuits 2a and 3a, 2c and 3c
Is a display 2 according to output signals from the CPUs 2b and 3b.
d, 3d is an output circuit for controlling.

[0003]

In such a configuration, the electric potential of the transmission line 5 becomes low (ground) level or high (power supply) level due to an electrical failure of the multiplex communication input circuit 2a (multiplex communication input circuit 3a). When fixed, the information output from the multiplex communication transmission unit 1 is not transmitted to the transmission line 5,
The multiplex communication receiving unit 3 (the multiplex communication receiving unit 2) which has not failed can no longer be received. as a result,
The entire multiplex communication system goes down. This is the same when the multiplex communication output circuit 1c fails.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a vehicular multiplex communication device for multiplexing signals through transmission lines connecting respective devices, comprising: at least one or more spare multiplex communication input circuits; Transmission line state determination means for determining whether or not the level of the signal is fixed, and switching means for switching to the spare multiplex communication input circuit when the transmission line state determination means determines that the level is fixed. .

Further, the spare multiplex communication input circuit is connected to a spare multiplex communication input terminal.

Further, in a vehicle multiplex communication device for multiplexing signals through a transmission line connecting each device, at least one or more spare multiplex communication output circuits, and whether or not the level of the signal of the transmission line is fixed is determined. A transmission line state determining means for determining and a switching means for switching to the standby multiplex communication output circuit when the level is determined to be fixed by the transmission line state determining means.

Further, the spare multiplex communication output circuit is connected to a spare multiplex communication output terminal.

In a multiplex communication apparatus for a vehicle for multiplexing a signal through a transmission line connecting each apparatus, at least one or more sets of spare multiplex communication input and output circuits and a fixed level signal of the transmission line are provided. A transmission line state determining means for determining the presence / absence, and a switching means for switching to the spare multiplex communication input and output circuit when the level is determined to be fixed by the transmission line state determining means.

Further, the spare multiplex communication input and output circuit is connected to a spare multiplex communication input and output terminal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multiplex communication input circuit 2a, 3 is connected between a transmission line 5 and a multiplex communication input terminal Rx of a CPU 2b, 3b.
a and auxiliary multiplex communication input circuits 2e and 3e are arranged in parallel, and the multiplex communication input circuits 2a and 3a are provided with switching means 2f,
A spare multiplex communication input circuit 2e which is connected to the transmission line 5 via the contact A 3f and is connected to the terminal Rx of the CPUs 2b and 3b also serving as the transmission line state determination means via the contact A of the switching means 2h and 3h. , 3e switching means 2f, 3e
f and 2f, 2h, 3f, which are connected to the transmission line 5 via the contact B of f and to the terminals Rx of the CPUs 2b, 3b via the contact B of the switching means 2h, 3h. , 3h are connected to the drive circuits 2g, 3g for controlling the switching of the contacts.
A faulty multiplex communication input circuit can be specified.

The switching means 2f and 3f connect the spare multiplex communication input circuits 2e and 3e to the multiplex communication input terminal R.
By connecting from x1 to the spare multiplex communication input terminal Rx2, not only can the multiplex communication input circuits 2a, 2e, 3a, 3e be switched, but also the terminals Rx1 of the CPUs 2b, 3b.
Rx2 can also be switched, and it is possible to cope with a case where the terminal Rx1 of the CPUs 2b and 3b fails.

The multiplex communication output terminal Tx of the CPU 1b
A multiplex communication output circuit 1c and a spare multiplex communication output circuit 1d are arranged in parallel between the
c is connected to the terminal Tx of the CPU 1b via the contact A of the switching means 1e and to the transmission line 5 via the contact A of the switching means 1f, and the spare multiplex communication output circuit 1d connects the contact B of the switching means 1e. Via the terminal T of the CPU 1b
x and the transmission line 5 via the contact B of the switching means 1f, and also serves as a transmission line state determination means.
The output port P0 of 1b is connected to a drive circuit 1g for controlling the switching of the contact points of the switching means 1e and 1f.
The terminal Rx of U1b is connected to the transmission line 5 via the drive circuit 1i constituting the transmission line state determination means and the normally open switching means 1h constituting the transmission line state determination means, and the CPU 1b
By connecting the output port P1 to the drive circuit 1j constituting the transmission line state determining means for closing the switching means 1h, a faulty multiplex communication output circuit can be specified.

Further, by connecting the spare multiplex communication output circuit 1d from the multiplex communication output terminal Tx1 to the spare multiplex communication output terminal Tx2 by the switching means 1f, the multiplex communication output circuits 1c and 1d are switched by the switching means 1f and 1g. As well as the terminals Tx1 and Tx2 of the CPU 1b.
Can also be switched, and it is possible to cope with a case where the terminal Tx1 of the CPU 1b fails.

A spare multiplex communication output circuit 6f and a spare multiplex communication input circuit 6g are juxtaposed with the multiplex communication output circuit 6c and the multiplex communication input circuit 6d, respectively. It is connected to the multiplex communication input terminal Rx2, the multiplex communication output circuit 6c and the multiplex communication input circuit 6d are connected to the transmission line 5 via the contact A of the switching means 6h, and the spare multiplex communication output circuit 6f and the spare multiplex communication input are connected. A driving circuit 6i for connecting the circuit 6g to the transmission line 5 via the contact B of the switching means 6h and controlling the switching of the contact of the switching means 6h to the output port P0 of the CPU 6b.
, It is possible to specify a multiplex communication input or output circuit that is faulty.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. 1 to 5. The same or corresponding parts as those in the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a first embodiment, in which multiplex communication receiving units 2 and 3 are provided with switching means 2f, 2h, 3f and 3 respectively.
h, drive circuits 2g and 3g and spare multiplex communication input circuits 2e and 3e. That is, the transmission line 5 and the CPU
The multiplex communication input circuits 2a and 3a and the spare multiplex communication input circuits 2e and 3e are connected between the multiplex communication input terminals Rx of the 2b and 3b.
Are arranged in parallel, and the multiplex communication input circuits 2a and 3a are connected to the transmission line 5 via the contact A of the switching means 2f and 3f, and are connected to the CPU via the contact A of the switching means 2h and 3h.
2b, 3b, and the redundant multiplex communication input circuits 2e, 3e are connected to the transmission line 5 via the contact B of the switching means 2f, 3f and the CPU 2b via the contact B of the switching means 2h, 3h. , 3b. The output ports P0 of the CPUs 2b and 3b are connected to drive circuits 2g and 3g for controlling the switching of the contacts of the switching means 2f, 2h, 3f and 3h.

In such a configuration, the transmission line
Is detected by the terminal Rx of the CPU 2b also serving as a transmission line state determination means. When the level has not changed (in an abnormal state), the output of the output port P0 of the CPU 2b is changed from a high level to a low level,
The switching means 2f and 2h are respectively switched from the contact A side to the contact B side by the drive circuit 2g, and the spare multiplex communication input circuit 2e is used. Thus, when the level of the transmission line 5 is fixed due to the failure of the multiplex communication input circuit 2a, the transmission line 5 returns. Thereafter, the switching means 2f and 2h continue to operate with the contact B. The multiplex communication input circuit 2e
If the level of the transmission line 5 is fixed even after the switching to the above, the cause of the fixed level is not due to the multiplex communication input circuit 2a. These processes are similarly performed for the multiplex communication receiving unit 3. As described above, when the level of the transmission line 5 is fixed, the multiplex communication input circuits 2a, 2e, 3a, and 3e are switched to disconnect the faulty circuit from the transmission line 5.

When the terminals Rx of the CPUs 2b and 3b fail, it is erroneously determined that the level of the transmission line 5 is fixed. In order to solve this, as shown in FIG. 2, switching means 2f and 3f switch the spare multiplex communication input circuits 2e and 3e from the multiplex communication input terminal Rx1 (terminal Rx in FIG. 1) to the spare multiplex communication input terminal. Connect to Rx2. Thereby, the multiplex communication input circuits 2a, 2e, 3a,
The above problem is solved by switching not only the terminal 3e but also the terminals Rx1 and Rx2 of the CPUs 2b and 3b.

FIG. 3 shows a second embodiment, in which multiplex communication transmitting unit 1 includes switching means 1e, 1f, and driving circuit 1
g, a switching line 1h serving as a transmission line state determining unit, driving circuits 1i and 1j, and a spare multiplex communication output circuit 1d. That is, the multiplex communication output circuit 1c is connected between the multiplex communication output terminal Tx of the CPU 1b and the transmission line 5.
And the standby multiplex communication output circuit 1d are arranged in parallel, and the multiplex communication output circuit 1c is connected to the switch C via the contact A of the switching means 1e.
Switching means 1f connected to terminal Tx of PU 1b
Of the multiplex communication output circuit 1d is connected to the transmission line 5 via the contact A of the switching means 1e.
It is connected to the terminal Tx of 1b and to the transmission line 5 via the contact B of the switching means 1f. Further, the output port P0 of the CPU 1b also serving as a transmission line state determination means is connected to a drive circuit 1g for controlling the contact switching of the switching means 1e and 1f. Further, the terminal R of the CPU 1b
x is a drive circuit 1i that constitutes a transmission line state determination unit and a normally open switching unit 1h that constitutes a transmission line state determination unit
To the transmission line 5 through the output port P of the CPU 1b.
1 is connected to a drive circuit 1j which constitutes a transmission line state determining means for closing the switching means 1h.

By changing the output of the output port P1 of the CPU 1b from a high level to a low level, the driving circuit 1
g by closing the switching means 1h,
It is determined whether the data input to the terminal Rx of U1b is different from the data transmitted from the terminal Tx, or whether the level of the transmission line 5 has changed within a predetermined time. Then, when the data is different or the level does not change (in the case of an abnormality), the output of the output port P0 of the CPU 1b is changed from the high level to the low level, whereby the driving circuit 1
The switching means 1e and 1f are respectively switched from the contact A side to the contact B side by g, and the spare multiplex communication output circuit 1d is used. Thereby, the transmission line 5 returns. Thereafter, the switching means 1e and 1f continue to operate with the contact B. In the case where the level of the transmission line 5 is fixed even after switching to the multiplex communication output circuit 1d, the cause is not due to the multiplex communication output circuit 1c. Thus, the multiplex communication output circuit 1
c, 1d are sequentially switched to disconnect the faulty circuit from the transmission line 5.

If the terminal Tx of the CPU 1b fails, an erroneous determination is made that the level of the transmission line 5 is fixed. To solve this, as shown in FIG. 4, the switching unit 1f connects the spare multiplex communication output circuit 1d from the multiplex communication output terminal Tx1 (terminal Tx in FIG. 3) to the spare multiplex communication output terminal Tx2. . Thus, not only the multiplex communication output circuits 1c and 1d are switched by the switching means 1f and 1g, but also the terminals Tx1 and Tx2 of the CPU 1b are switched, thereby solving the above-described problem.

FIG. 5 shows a third embodiment, in which a multiplex communication transmitting / receiving unit 6 in which the multiplex communication receiving units 2 and 3 of the first embodiment and the multiplex communication transmitting unit 1 of the second embodiment are combined.
An application example in the case of is shown. The multiplex communication transmission / reception unit 6 sends ON / OFF information of the switch group 4 to the CPU 6b (2 in FIG. 1) via the input circuit 6a (1a in FIG. 3).
b, 3b and 1b) in FIG. The CPU 6b
The on / off information of the switch group 4 is transmitted to the multiplex communication output terminal Tx
1 and transmitted to the transmission line 5 through the multiplex communication output circuit 6c (1c in FIG. 3). The multiplex communication transmitting / receiving unit 6 includes a multiplex communication input circuit 6d (2 in FIG. 1).
a, 3a) based on the information received at the multiplex communication input terminal Rx1 via the output circuit 6e (2c, 3c in FIG. 1).
, The actuator 7 such as a display is controlled. A spare multiplex communication output circuit 6f (1d in FIG. 3) and a spare multiplex communication input circuit 6g (2e and 3e in FIG. 1) are provided in parallel with the multiplex communication output circuit 6c and the multiplex communication input circuit 6d, respectively.
U6b is connected to the spare multiplex communication output terminal Tx2 and the spare multiplex communication input terminal Rx2, and the multiplex communication output circuit 6c and the multiplex communication input circuit 6d are connected to the switching means 6h.
(2f, 3f in FIG. 1 and 1f in FIG. 3) are connected to the transmission line 5 via the contact A, and the spare multiplex communication output circuit 6f and the spare multiplex communication input circuit 6g connect the contact B of the switching means 6h. The output port P0 of the CPU 6b is connected to a drive circuit 6i (2g, 3g in FIG. 1 and 1g in FIG. 3) for controlling the contact switching of the switching means 6h.

In such a configuration, the transmission line 5 can be
Is detected by the terminal Rx1 of the CPU 6b also serving as a transmission line state determination unit. If the level has not changed (in the case of an abnormality), the output port P0 of the CPU 6b
Is changed from the high level to the low level, the switching means 6h is switched from the contact A to the contact B by the drive circuit 6i, and the spare multiplex communication output circuit 6f and the spare multiplex communication input circuit 6g are used. Thus, when the level of the transmission line 5 is fixed, the transmission line 5 returns. After that, the switching means 6h continues the operation with the contact B kept. If the level of the transmission line 5 is fixed even after switching, the cause of the fixed level is the multiplex communication output circuit 6.
c and / or the multiplex communication input circuit 6d, so that it is switched to the multiplex communication output circuit 6c and the multiplex communication input circuit 6d again. As described above, when the level of the transmission line 5 is fixed, the faulty circuit is disconnected from the transmission line 5.

In this embodiment, as in the first or second embodiment, the spare multiplex communication output terminal Tx2 and the spare multiplex communication input terminal Rx2 of the CPU 6b are connected to the multiplex communication output terminal Tx1 and the multiplex communication input terminal, respectively. It may be shared with Rx1.

Although the switching means 1e, 1f, 1h, 2f, 3f, 2h, 3h, 6h in each of the above embodiments are relays, other means may be used.

[0026]

As described above, according to the present invention, the transmission line state determining means for determining whether or not the signal level of the transmission line is fixed, and when the transmission line state determining means determines that the level is fixed, the spare multiplex communication input signal is output. A switching means for switching between the circuit and / or the multiplex communication output circuit, a malfunctioning multiplex communication input or output circuit can be specified, and a non-failure spare multiplex communication input or output circuit can be switched. Can be used, and the reliability of the multiplex communication system is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an application example of the embodiment.

FIG. 3 is a block diagram illustrating a configuration of a second embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of an application example of the embodiment.

FIG. 5 is a block diagram illustrating a configuration of a third embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 multiplex communication transmitting unit 1a input circuit 1b CPU (transmission line state determination means) 1c multiplex communication output circuit 1d spare multiplex communication output circuit 1e switching means 1f switching means 1g drive circuit 1h switching means (transmission line state determination means) 1i driving Circuit (transmission line state determining means) 1j Drive circuit (transmission line state determining means) Tx, Tx1 Multiplexed communication output terminal Tx2 Spare multiplexed communication output terminal 2, 3 Multiplexed communication receiving unit 2a, 3a Multiplexed communication input circuit 2b, 3b CPU (Transmission line state determining means) 2c, 3c Output circuit 2d, 3d Display 2e, 3e Spare multiplex communication input circuit 2f, 3f Switching means 2g, 3g Driving circuit 2h, 3h Switching means Rx, Rx1 Multiple communication input terminal Rx2 Reserve Multiplex communication input terminal 5 transmission line 6 multiplex communication transmission / reception unit 6a input Circuit 6b CPU (transmission line status determination means) 6c multiplex communication output circuit 6d multiplex communication input circuit 6e output circuit 6f spare multiplex communication output circuit 6g spare multiplex communication input circuit 6h switching means 6i drive circuit

Claims (6)

[Claims] 1. A vehicular multiplex communication device for multiplexing a signal through a transmission line connecting each device, wherein at least one or more spare multiplex communication input circuits and whether or not the level of the signal on the transmission line is fixed. A multiplex communication apparatus for a vehicle, comprising: a transmission line state determining means for determining; and a switching means for switching to the standby multiplex communication input circuit when the transmission line state determining means determines that the level is fixed. 2. The spare multiplex communication input circuit is connected to a spare multiplex communication input terminal.
A multiplex communication device for a vehicle according to claim 1. 3. A vehicular multiplex communication device for multiplexing signals via transmission lines connecting respective devices, wherein at least one or more spare multiplex communication output circuits and a signal level of the transmission line are fixed. A multiplex communication apparatus for a vehicle, comprising: a transmission line state determining means for determining; and a switching means for switching to the standby multiplex communication output circuit when the level is determined to be fixed by the transmission line state determining means. 4. The spare multiplex communication output circuit is connected to a spare multiplex communication output terminal.
A multiplex communication device for a vehicle according to claim 1. 5. A vehicular multiplex communication device for multiplexing signals through transmission lines connecting respective devices, wherein at least one or more sets of spare multiplex communication input and output circuits and a fixed level signal of the transmission lines are provided. A transmission line state determining means for determining the presence / absence, and a switching means for switching to the spare multiplex communication input and output circuit when the level is determined to be fixed by the transmission line state determining means. Multiplex communication device. 6. The vehicular multiplex communication device according to claim 5, wherein said spare multiplex communication input and output circuit is connected to a spare multiplex communication input and output terminal.