JP3385162B2 - Vehicle multiplex transmission equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle multiplex transmission device, and more particularly to a vehicle multiplex transmission device for reducing the data occupation rate per unit time.

[0002]

2. Description of the Related Art In a vehicle multiplex transmission apparatus, a plurality of units are connected to a bus to serially multiplex vehicle driving information. For example, an engine system unit, a body system unit, a meter multiplex unit, etc. are connected to the bus, and data is transmitted and received to and from other communication units via the bus.

In this case, the speed of data transferred on the bus is, for example, a low speed of about 10 kbps and 10 kbp.
It can be classified into medium speed of about s to 100 kbps and high speed of about 100 to 1 Mbps, and data from low speed to high speed from various parts such as a lamp and an engine passes through the bus.

As a known technique of this type of vehicle multiplex transmission device, for example, there is one described in Japanese Patent Laid-Open No. 6-169488. In this vehicle multiplex transmission device, as shown in FIGS. 5 (a) and 5 (b), a data frame is an SOM indicating the start of a message, a PRI for determining a priority when a plurality of units simultaneously transmit data, and a variable PRI. Long data areas DATA1 to DATA6, error check code CRC, EOD indicating the end of data, reception signal area RSP for returning a reception signal in bit correspondence from all units, EOM indicating the end of a message, indicating the end of a data frame It is composed of an idle area IDL.

In FIG. 5A, among the main data,
DA for each data of speedometer and tachometer with short data transfer cycle
Auxiliary data SOM-I stored in TA1 and DATA2
A DL is attached to form one data frame.

Further, as shown in FIG. 5 (b), among the main data, each data having a data transfer cycle from the fuel gauge to the alarm indicator is stored in DATA3 to DATA6, and auxiliary data SOM to IDL are added. , Constitutes one data frame.

That is, since the former data frame is transferred at a short cycle and the latter data frame is transferred at a relatively long cycle, it is composed of data having a short data transfer cycle and other data having a long data transfer cycle. The data occupation rate per unit time is reduced as compared with the conventional method in which data frames are transferred in a short cycle.

Further, when the data described in Japanese Patent Laid-Open No. 6-169488 is used to transfer each data from one unit to another unit via a bus, a predetermined base time is set for each data. T1, T2 ... Tn
Each data is transferred for each.

For example, data from a data having a short transfer cycle to data having a longest transfer cycle is classified into several classes, and as shown in FIG. 6, the count time is time T1.
(For example, 20 ms) (step S101),
The data D1 is transferred (step S102).

The counting time is time T2 (for example, 100
ms) (step S103), the data D2 is transferred (step S104), and when the count time reaches the time Tn (for example, 1s) (step S10n-).
1), the data Dn is transferred (step S10n).

[0011]

However, when a large amount of data is transmitted by a certain unit, the occupation rate on the bus increases, so that the data transmission of other units is significantly limited.

Further, when data is transferred at high speed, there are problems that noise is increased and the shield effect is reduced.

Therefore, if the data is transferred as slowly as possible, the data occupation rate is reduced. That is, since the time division multiplex system is adopted, the lower the occupation rate of data from a certain unit, the easier the data from another unit enters the bus, and the smaller the data transmission delay.

Therefore, it has been desired to use the bus efficiently at a transfer rate (baud rate) as low as possible.

Therefore, an object of the present invention is to provide a vehicle multiplex transmission device capable of efficiently transmitting data from a plurality of units by reducing the data occupation rate.

[0016]

The present invention adopts the following means in order to solve the above problems. The invention of claim 1 comprises a bus and a plurality of communication units connected to the bus, each communication unit transmitting and receiving data to and from other units, and transmitting the previously transmitted data. A counter that counts time from time and data to be transmitted change, and the time counted from the transmission time of the previously transmitted data to the change time of the data to be transmitted is set to the data to be transmitted. When it is longer than the minimum processing time, the transmission / reception unit is instructed to transmit the data to be transmitted, or the data to be transmitted does not change, and the counted time is set to the data to be transmitted. A data transmission instructing unit for instructing the transmitting and receiving unit to transmit the data to be transmitted when the maximum processing time is reached, and the data includes a plurality of data having different transfer cycles. Made over data, the data transmission instruction section, for each different data of the transfer period, and sets the minimum processing time and the maximum processing time.

According to the present invention, the counter counts the time from the transmission time of the data transmitted last time, and the data transmission instructing section changes the data to be transmitted from the transmission time of the data transmitted last time. When the time counted by the change time of the data to be transmitted is longer than the minimum processing time set for the data to be transmitted, the transmission / reception unit is instructed to transmit the data to be transmitted.

Further, the data transmission instructing section is arranged such that the data to be transmitted does not change and the counted time is
When the maximum processing time set for the data to be transmitted has been reached, the transmission / reception unit is instructed to transmit the data to be transmitted. The data is composed of a plurality of data having different transfer cycles, and the data transmission instruction unit sets the minimum processing time and the maximum processing time for each data having different transfer cycles.

That is, when the data changes, the data is transmitted at least for a time exceeding the minimum processing time set for the data to be transmitted, and when the data does not change, at least the data to be transmitted is set. Since the data is transmitted in the maximum processing time, the data transfer rate becomes low. As a result, since the data occupation rate is reduced, more data can be efficiently transmitted and received between the plurality of units. Further, since the minimum processing time and the maximum location time are set for each data having different transfer rates, the data occupation rate is further reduced.

The invention of claim 2 comprises a bus and a plurality of communication units connected to the bus, each communication unit transmitting and receiving data to and from other units, and a transmission unit previously transmitted. A counter that counts time from the data transmission time, and the data to be transmitted changes, and the time counted from the transmission time of the previously transmitted data to the change time of the data to be transmitted is the data to be transmitted. When it is longer than the minimum processing time set to, the transmission / reception unit is instructed to transmit the data to be transmitted, or the data to be transmitted does not change, and the counted time becomes the data to be transmitted. And a data transmission instructing unit for instructing the transmitting and receiving unit to transmit the data to be transmitted when the set maximum processing time is reached, and the data transmission instructing unit, When the transmission of the data to be signal instructs the transceiver unit, and outputs a reset signal for resetting the counted time to the counter.

According to the present invention, the data transmission instructing section is
Since the reset signal for resetting the counted time is output to the counter, the counter is reset by the reset signal and the time is counted from the transmission time of the data transmitted this time. .

The invention of claim 3 comprises a bus and a plurality of communication units connected to the bus, each communication unit transmitting / receiving data to / from another unit, and a transmission unit previously transmitted. A counter that counts time from the data transmission time, and the data to be transmitted changes, and the time counted from the transmission time of the previously transmitted data to the change time of the data to be transmitted is the data to be transmitted. When it is longer than the minimum processing time set to, the transmission / reception unit is instructed to transmit the data to be transmitted, or the data to be transmitted does not change, and the counted time becomes the data to be transmitted. A data transmission instructing unit for instructing the transmitting and receiving unit to transmit the data to be transmitted when the set maximum processing time is reached, The data transmission instructing section sets the minimum processing time and the maximum processing time for each data having a different transfer cycle, and the data transmission instructing section transmits the data to be transmitted. When the transmission / reception unit is instructed, a reset signal for resetting the counted time is output to the counter.

According to the present invention, since the minimum processing time and the maximum location time are set for each data having different transfer rates, the data occupation rate is further reduced. Further, the data transmission instruction unit outputs a reset signal for resetting the counted time to the counter, so that the counter resets the counted time by the reset signal, and the transmission time of the data transmitted this time. It will count the time from.

[0024] In the invention of claim 4, the data transmission instructing section changes the data to be transmitted and the counted time is shorter than a minimum processing time set in the data to be transmitted. Alternatively, when the data to be transmitted does not change and the counted time is smaller than the maximum processing time set for the data to be transmitted, a transfer cycle longer than the transfer cycle of the data to be transmitted is set. It is characterized in that the transmission instruction of the data included therein is determined based on the minimum processing time and the maximum processing time set for the data.

According to the present invention, when certain data to be transmitted has changed and the counted time is smaller than the minimum processing time set for the data to be transmitted, or some data to be transmitted. Does not change, and when the counted time is smaller than the maximum processing time set for the data to be transmitted, a transmission instruction of data having a transfer cycle longer than the transfer cycle of the data to be transmitted is issued. , The data occupancy rate is reduced for each data with a different transfer cycle because it is determined based on the minimum processing time and the maximum processing time set for that data, so more data can be efficiently transferred between multiple units. You can send and receive well.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a vehicle multiplex transmission apparatus will be described below with reference to the drawings. FIG. 1 shows a block diagram of an embodiment of a vehicle multiplex transmission device. In FIG. 1, the bus 3 includes a body system unit 1a, a meter system unit 1b,
The display system unit 1c and the other unit 1d are connected, and data is mutually transmitted and received between the units.

The body system unit 1a includes a CPU (central processing unit) 11a and a CAN (control area network) 20a connected to the CPU 11a. CA
The N20a includes a transmission / reception unit 21a, a data processing unit 23a, an event generation unit 25a, a counter 27a, and a data transmission instruction unit 29a.

The body system unit 1a includes a sensor 31 and a switch 3 which are provided at various parts of the vehicle to detect a running state.
3 are connected. Although only one sensor 31 and one switch 33 are shown in FIG. 1, it is assumed that a plurality of sensors 31 and switches 33 are actually provided.

The body system unit 1a outputs the traveling distance data, the battery voltage data, the engine speed data, the speed data, the remaining fuel amount data, the temperature data and the like detected by the sensor 31 to the bus 3.

The meter system unit 1b includes a CPU 11b,
The CAN 20b is connected to the CPU 11b. CA
The N20b includes a transmission / reception unit 21b, a data processing unit 23b, an event generation unit 25b, a counter 27b, and a data transmission instruction unit 29b.

In the meter system unit 1b, the traveling distance data from the body system unit 1a, the battery voltage data,
A meter 35 indicating the engine speed data, speed data, remaining fuel amount data, temperature data, etc. is connected.

The display system unit 1c includes CPUs 11c and C.
A CAN 20c connected to the PU 11c is provided. CAN
20c includes a transmission / reception unit 21c, a data processing unit 23c, an event generation unit 25c, a counter 27c, and a data transmission instruction unit 29c.

The display system unit 1c is connected to a multiple display device 37 for displaying a message based on the traveling distance data, battery voltage data, speed data, remaining fuel amount data and failure alarm data from the body system unit 1a. It

Since the other units 1d have almost the same structure as the above-mentioned units, their details are omitted here.

Each of the transmission / reception units 21a to 21d transmits data to another unit and receives data from the other unit. Each of the data processing units 23a to 23d inputs data from the sensor 31 and the switch 33, and processes data received by the transmitting / receiving units 21a to 21d.

Each of the event generators 25a to 25d is
When an external input signal is input, it is determined that an event has occurred and the external input signal is sent to the data processing unit 23a. Each of the counters 27a to 27d counts time from the transmission time of the previously transmitted data.

Each of the data transmission instructing units 29a to 29d changes the data to be transmitted from the transmission time of the data transmitted last time when the data to be transmitted in the data processing unit 23a is changed by the external input signal. It is determined whether the time counted up to the time is longer than the minimum processing time set for the data to be transmitted, and when the counted time is larger than the minimum processing time set for the data to be transmitted, Instruct the corresponding transmitting / receiving unit to transmit the data to be transmitted.

When the data to be transmitted does not change, each of the data transmission instructing units 29a to 29d determines whether or not the counted time has reached the maximum processing time set for the data to be transmitted, and counts. When the maximum processing time set for the data to be sent has been reached,
Instruct the corresponding transmitting / receiving unit to transmit the data to be transmitted.

The minimum processing time and the maximum processing time are set for the following reason. If data is transmitted only by a change in the data to be transmitted, a change occurs frequently in the case of data having a short transfer cycle such as the engine speed, which causes a problem. Therefore, by setting the minimum processing time, the data to be transmitted is transmitted at least for a time exceeding the minimum processing time.

When the data to be transmitted does not change, no data is transmitted. Therefore, at least the data is transmitted within the maximum processing time set for the data to be transmitted.

As in the case of the data frame shown in FIG. 5A, the data contains an SO indicating the start of a message.
M, PRI that determines priority when multiple units simultaneously transmit data, error check code CRC,
Additional information such as an EOD indicating the end of data, a reception signal area RSP for returning a reception signal in bit correspondence from all units, an EOM indicating the end of a message, and an idle area IDL indicating the end of a data frame are added.

Next, an embodiment of the vehicle multiplex transmission device configured as described above will be described with reference to the drawings. FIG. 2 shows a flowchart for explaining the operation of the embodiment. FIG. 3 shows a timing chart for explaining the operation of the embodiment.

First, for speed data or engine speed data whose transfer cycle is relatively short, the minimum processing time is set to, for example, 20 ms, and the maximum processing time is, for example, 12
It is assumed that it is set to 0 ms.

For gauge data with a medium transfer cycle, the minimum processing time is set to, for example, 500 ms, and the maximum processing time is set to, for example, 1 s. For lamp data or door opening / closing data with a relatively long transfer cycle, the minimum processing time is set to 1 s, and the maximum processing time is set to, for example,
It shall be set to 10 s.

First, when the plurality of sensors 31 detect the traveling distance, the battery voltage, the remaining fuel amount, the engine speed, the speed, the temperature, the gauge, the turning on / off of the lamp, and the opening / closing of the door, these are detected. The data is input to the data processing unit 23a of the CAN 20a in the body system unit 1a.

In the CAN 20a, the transmission / reception unit 21a sequentially transfers the plurality of detected data from the data processing unit 23a from the one having the shortest transfer cycle to all other units 1.
b, 1c, 1d will be transmitted.

For example, speed data and engine speed data have a relatively short transfer cycle, and lamp data and door opening / closing data have a relatively long transfer cycle. In addition, the gauge data has a relatively medium transfer cycle.

In this case, when the event generating unit 25a receives an external input signal, it is determined that an event has occurred and sends the external input signal to the data processing unit 23a. Further, the counter 27a counts time from the transmission time t1 of the speed data D1 (pulse P10) transmitted last time.

The data transmission instructing section 29a uses the data D1 having a relatively short transfer cycle in the data processing section 23a, for example,
It is determined whether or not the speed data and the engine speed data to be transmitted have changed depending on "presence or absence" of the external input signal (step S11).

Here, when the speed data D1 (pulse P2) to be transmitted changes at time t2,
The data transmission instruction unit 29a indicates that the time T _X11 counted from the transmission time t1 of the previously transmitted speed data D1 (pulse P10) to the change time t2 of the speed data D1 (pulse P2) to be transmitted is the speed data D1.
It is determined whether it is _longer than the minimum processing time T _1MIN set to 1 (step S13).

When the counted time T _X11 is _longer than the minimum processing time T _1MIN set in the speed data D1, the data transmission instruction unit 29a instructs the transmission / reception unit 21a to transmit the speed data D1 to be transmitted. Since the instruction is given, the transmission / reception unit 21a transmits the speed data D1 (pulse P11) to be transmitted at time t2 (step S15).

Further, the data transmission instructing section 29a sends a reset signal for resetting the counted time _Tx11 to the counter 27a, and the counter 27a is reset by the reset signal (step S17).
Further, the counter 27a starts counting time from time t2. After resetting the counter 27a, the process returns to the process of step S11.

Next, in step S11, when the speed data D1 to be transmitted does not change due to "absence" of the external input signal, the data transmission instructing section 29a indicates that the counted time T _X12 is the speed data D1. It is determined whether or not the maximum processing time T _1MAX set in step ₁ has been reached (step S19).

When the counted time T _X12 reaches the maximum processing time T _1MAX set in the speed data D1, the data transmission instruction unit 29a instructs the corresponding transmission / reception unit 21a to transmit the data to be transmitted. Since the instruction is given, the transmission / reception unit 21a causes the speed data D1 to be transmitted.
(Pulse P12) is transmitted at time t3 (step S1)
5).

Further, the data transmission instructing section 29a is
A reset signal for resetting the counted time T _X12 is sent to the counter 27a, and the counter 27a is reset by the reset signal (step S1).
7). Further, the counter 27a starts counting time from time t3. After resetting the counter 27a, the process returns to the process of step S11.

Next, in step S13, when the time counted from the transmission time of the previously transmitted data to the change time of the data to be transmitted is smaller than the minimum processing time set for the data to be transmitted, Alternatively, in step S19, when the counted time is smaller than the maximum processing time set for the data to be transmitted, the gauge data D2 to be transmitted having the second longest transfer cycle after the transfer cycle of the transmitted speed data. Transmission determination processing is performed.

For example, in the example shown in FIG. 3, counting is performed from the transmission time t3 of the previously transmitted speed data D1 (pulse P12) to the transmission time t4 of the speed data D1 (pulse P3) to be transmitted. Time T
_{Since X13} is smaller than the minimum processing time T _1MIN set in the speed data D1, the transmission data of the gauge data D2 to be transmitted is determined.

The data transmission instructing section 29a determines whether or not the data D2 having a medium transfer cycle in the data processing section 23a, for example, the gauge data to be transmitted has changed due to "presence or absence" of the external input signal. Judge (step S
21).

If the gauge data D2 (pulse P22) to be transmitted changes at time t6,
The data transmission instruction unit 29a indicates that the time T _X21 counted from the transmission time t5 of the gauge data D2 (pulse P25) transmitted last time to the change time t6 of the gauge data D2 (pulse P22) to be transmitted is the gauge data D2. It is determined whether or not it is _longer than the minimum processing time T _2MIN set for (step S23).

The data transmission instruction unit 29a instructs the transmission / reception unit 21a to transmit the gauge data D2 to be transmitted when the counted time T _X21 is _longer than the minimum processing time T _2MIN set in the gauge data D2. Therefore, the transmission / reception unit 21a uses the gauge data D2 to be transmitted.
(Pulse P26) is transmitted at time t6 (step S2
5).

Further, the data transmission instructing section 29a sends a reset signal for resetting the counted time T _X21 to the counter 27a, and the counter 27a is reset by the reset signal (step S27).
Further, the counter 27a starts counting time from time t6. After resetting the counter 27a, the process returns to the process of step S21.

Next, in step S21, when the gauge data D2 to be transmitted does not change due to the absence of the external input signal, the data transmission instructing section 29a indicates that the counted time T _X22 is the gauge data D2. It is determined whether or not the maximum processing time T _2MAX set in step ₂ has been reached (step S29).

When the counted time T _X22 reaches the maximum processing time T _2MAX set in the gauge data D2, the data transmission instruction unit 29a instructs the corresponding transmission / reception unit 21a to transmit the data to be transmitted. Since the instruction is given, the transmission / reception unit 21a causes the gauge data D2 to be transmitted.
(Pulse P27) is transmitted at time t7 (step S2
5).

Further, the data transmission instructing section 29a is
A reset signal for resetting the counted time T _X22 is sent to the counter 27a, and the counter 27a is reset by the reset signal (step S2).
7). Further, the counter 27a starts counting time from time t7. After resetting the counter 27a, the process returns to the process of step S21.

Then, the above-described speed data and gauge data transmission determination processing is repeated for the remaining data. In this case, the data transmission determination process is performed in the order of shorter transfer cycle.

Finally, data transmission determination processing is performed for the data having the longest transfer cycle, for example, lamp data and door opening / closing data (step Sn1 to step Sn9).

In this way, each data transferred from the body system unit 1a to the bus 3 is stored in the meter system unit 1
b, the display system unit 1c, and the other unit 1d. The meter system unit 1b sends each input data to the meter 35 via the CAN 20b and the CPU 11b.

As a result, in the meter 35 shown in FIG. 4, the engine speed is indicated by the tachometer 41 and the speed is indicated by the speedometer 43. The battery voltage is indicated by the battery voltmeter 45, the temperature is indicated by the thermometer 47, and the remaining fuel amount is indicated by the fuel gauge 49.

In the display system unit 1c, each input data is sent to the multiplex display 37 through the CAN 20c and the CPU 11c. As a result, messages are displayed, doors are opened and closed, and so on.

As described above, according to the above-described embodiment, by setting the minimum processing time, the data to be transmitted is transmitted for a time exceeding at least the minimum processing time. As described above, even if the data has a short transfer cycle, no trouble occurs.

Further, even when the data to be transmitted does not change, the data is transmitted within the maximum processing time set for the data to be transmitted, so that the data transfer rate becomes low. As a result, since the data occupation rate is reduced, more data can be efficiently transmitted and received between the plurality of units.

Further, since the minimum processing time and the maximum processing time are set for each data having a different transfer rate,
Data occupancy is reduced.

Further, the counter is reset by the reset signal, and the time can be counted from the transmission time of the data transmitted this time.

The present invention is not limited to the above embodiment. The form of the network is not limited to the network form described in the above embodiment, and may be a token passing system in which each unit connected to the bus sequentially obtains the transmission right (priority right). It may be in network form.

[0075]

According to the present invention, the counter counts the time from the transmission time of the data transmitted last time, and the data transmission instructing section changes the data to be transmitted from the transmission time of the data transmitted last time. When the time counted until the change time of the data to be transmitted is longer than the minimum processing time set for the data to be transmitted, the transmission / reception unit is instructed to transmit the data to be transmitted.

Further, the data transmission instructing section transmits the data to be transmitted when the data to be transmitted does not change and the counted time reaches the maximum processing time set for the data to be transmitted. Instruct the transceiver.

That is, when the data changes, the data is transmitted at least for a time exceeding the minimum processing time set for the data to be transmitted, and when the data does not change, the maximum set for the data to be transmitted is set. Since the data is transmitted within the processing time, the data transfer rate becomes low. As a result, since the data occupation rate is reduced, more data can be efficiently transmitted and received between the plurality of units.

Since the minimum processing time and the maximum processing time are set for each data having different transfer rates,
Data occupancy is reduced.

Further, since the data transmission instructing section outputs the reset signal for resetting the counted time to the counter, the counter is reset by the reset signal for resetting the counted time. The time can be counted from the transmission time of the transmitted data.

When the data to be transmitted has changed and the counted time is shorter than the minimum processing time set for the data to be transmitted, or the data to be transmitted has not changed, and When the counted time is smaller than the maximum processing time set for the data to be transmitted, a data transmission instruction having a transfer cycle longer than the transfer cycle of the data to be transmitted is set to the data. Since it is determined based on the minimum processing time and the maximum processing time,
Since the data occupation rate is reduced, more data can be efficiently transmitted / received between the plurality of units.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a vehicle multiplex transmission apparatus of the present invention.

FIG. 2 is a flowchart for explaining the operation of the vehicle multiplex transmission device.

FIG. 3 is a timing chart for explaining the operation of the vehicle multiplex transmission device.

FIG. 4 is a diagram showing a detailed configuration of a meter in the vehicle multiplex transmission device.

FIG. 5 is a diagram showing an example of a data frame of a conventional vehicle multiplex transmission device.

FIG. 6 is a flowchart showing the operation of another example of the conventional vehicle multiplex transmission device.

[Explanation of symbols]

1a Body system unit 1b Meter system unit 1c Display system unit 1d Other unit 11a-11d CPU 20a-20d CAN 21a-21d Transmitter / receiver 23a-23d Data processor 25a-25d Event generator 27a-27d Counter 29a-29d Data transmit Indicator 31 Sensor 33 Switch 35 Meter 37 Multiple display 41 Tachometer 43 Speedometer 45 Battery voltmeter 47 Thermometer 49 Fuel gauge T _1MIN Minimum processing time T _1MAX Maximum processing time D1, D2 data

Claims (4)

(57) [Claims] 1. A bus and a plurality of communication units connected to the bus, each communication unit transmitting and receiving data to and from other units, and a transmission time of the data transmitted last time. The counter that counts time and the data to be transmitted change, and the time counted from the transmission time of the previously transmitted data to the change time of the data to be transmitted is the minimum set in the data to be transmitted. When it is longer than the processing time, it instructs the transmission / reception unit to transmit the data to be transmitted, or the data to be transmitted does not change, and the counted time is the maximum processing set in the data to be transmitted. And a data transmission instruction unit that instructs the transmission / reception unit to transmit the data to be transmitted when the time is reached. Consist data, the data transmission instruction section, for each different data of transfer period, the vehicle multiplex transmission apparatus characterized by setting the minimum processing time and the maximum processing time. 2. A bus and a plurality of communication units connected to the bus, each communication unit transmitting and receiving data to and from other units, and a transmission time of the data transmitted last time. The counter that counts time and the data to be transmitted change, and the time counted from the transmission time of the previously transmitted data to the change time of the data to be transmitted is the minimum set in the data to be transmitted. When it is longer than the processing time, it instructs the transmission / reception unit to transmit the data to be transmitted, or the data to be transmitted does not change, and the counted time is the maximum processing set in the data to be transmitted. And a data transmission instructing unit for instructing the transmitting and receiving unit to transmit the data to be transmitted when the time is reached. When the transmission was instructed to the transceiver unit, a vehicle multiplex transmission apparatus characterized by outputting a reset signal for resetting the counted time to the counter. 3. A bus and a plurality of communication units connected to the bus, each communication unit transmitting and receiving data to and from other units, and a transmission time of the previously transmitted data. The counter that counts time and the data to be transmitted change, and the time counted from the transmission time of the previously transmitted data to the change time of the data to be transmitted is the minimum set in the data to be transmitted. When it is longer than the processing time, it instructs the transmission / reception unit to transmit the data to be transmitted, or the data to be transmitted does not change, and the counted time is the maximum processing set in the data to be transmitted. And a data transmission instruction unit that instructs the transmission / reception unit to transmit the data to be transmitted when the time is reached. The data transmission instructing unit sets the minimum processing time and the maximum processing time for each data having a different transfer cycle, and the data transmission instructing unit transmits the data to be transmitted to the transmitting / receiving unit. A vehicle multiplex transmission device, which outputs a reset signal for resetting the counted time to the counter when instructed. 4. The data transmission instruction unit, when the data to be transmitted has changed and the counted time is shorter than the minimum processing time set for the data to be transmitted, or should be transmitted. A data transmission instruction having a transfer cycle longer than the transfer cycle of the data to be transmitted when the data does not change and the counted time is smaller than the maximum processing time set for the data to be transmitted. 4. The vehicle multiplex transmission device according to claim 1, wherein the data is determined based on the minimum processing time and the maximum processing time set in the data.