JPH0440033A - Data transmission system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data transmission system in which a plurality of communication devices communicate via a common transmission path.

[Prior art]

As a conventional data transmission system, there is one shown in FIG. 5, for example. FIG. 5 shows the receiving section 5 of the communication device.
00, the configuration of the transmitter of the communication device is not shown. In FIG. 5, a receiving unit 500 of a communication device has a configuration including a receiving unit 501 that receives transmission data input via a transmission path 100, and a storage unit 50 that stores the transmission data received by the receiving unit 501.
2, a data output means 503 that decodes the transmission data stored in the storage means 502 and outputs an output signal based on the decoded information to the outside, a reception means 501, and a storage means 502.
and reception control means 5 for controlling data output means 503
04. In addition, the receiving unit 5 of communication @
The output signal of 00 is input to the load drive circuit 510, and the load drive circuit 510 drives the load 520.

Next, the reception operation of the conventional data transmission system will be explained using FIG. For example, consider a case where some communication device (not shown) transmits transmission data having information for operating the load 520.

When this transmission data is input to the reception unit 500 of the communication device via the transmission path 100, the reception means 501 sends a signal to the reception control means 500 notifying that the transmission data has been input.
4 and starts receiving transmission data. The reception control means 504 controls the reception means 501 and the storage means 5.
02 outputs a control signal instructing the timing to store the received transmission data. Based on this control signal, the storage means 502 stores the transmission data. Further, the transmission data stored in the storage means 502 is transmitted to the data output means 50
The data output means 503 decodes the transmitted data and reads information for operating the load 520.
An output signal for driving 0 is output to the load drive circuit 510. Load drive circuit 510 drives load 520 based on this output signal.

[The invention tries to solve i! Problem] However, in the conventional data transmission system described above, the receiving unit 500 of the communication device stores only the transmission data received by the receiving means 501 in the storage means 502, and the transmission data stored in the storage means 502 The configuration was such that the load 520 was controlled based on. Therefore, for example, if transmission data cannot be received due to a failure in the transmission path 100, or if the interval at which transmission data can be received becomes extremely long, even if the circumstances surrounding the load 520 change over time, The load 520 continues to be controlled based on the old transmission data stored in the storage means 502 until new transmission data is received. In other words, even if the effectiveness of the transmission data stored in the storage means 502 decreases over time until new transmission data is received, the problem is that the old transmission data continues to be used for control. there were.

This invention was made in order to solve the above-mentioned problems, and is a data transmission system that can determine the validity of transmitted data that has been received and stored, and can appropriately control the system. is intended to provide.

[Means to solve the problem]

This invention was made in view of the above-mentioned problems.
The receiving unit of the communication device includes a receiving unit that receives transmission data from a transmission path, a time data creation unit that creates time data, and a storage data creation unit that adds time data to the transmission data to form storage data. , a storage means for storing stored data, and a comparing and determining means for determining the validity of the stored data based on a comparison between current time data and time data stored in the storage means.

[Effect]

In the reception section of the communication device, when the transmission data is input to the reception means via the transmission path, the time data creation means outputs the time data created, and the storage data creation means adds the time data to the transmission data. Storage data is formed, and the storage means stores the storage data. The comparison determination means determines the validity of the stored data based on the comparison between the time data indicating the current time inputted at predetermined time intervals and the time data included in the stored data. It becomes possible to perform processing such as requesting the transmission of transmission data or performing data inference from stored data when it is determined that the data transmission system has decreased, making it possible to perform appropriate control of the data transmission system. .

〔Example〕

Hereinafter, description will be given based on specific examples.

FIG. 1 shows one embodiment of the invention. The data transmission system using this embodiment uses C8MA/CD (Carrier 5en), which is one of the most commonly used access methods among communication control methods due to its simplicity.
se Hultipule Access/Co11i
It is assumed that communication is performed using the sionDetect 1on) method.

FIG. 1 is a block diagram showing the configuration of the communication device N10.
8 and a comparison/judgment means 110, a transmission section consisting of a transmission data creation means 116, a transmission means 11'8, and a carrier sense means 120, a communication control means 112 for controlling these transmission and reception sections, and an external circuit (specifically,
Data means 1 for inputting and outputting data with (shown in Figure 2)
It consists of 14.

In the receiving section of the communication device 10, when the power switch (not shown) of the data transmission system is turned on, the communication control means 1
12 outputs a control signal 102a instructing the receiving means 102 to start operation. When receiving the control signal 102a, the receiving means 102 becomes ready to receive data, and when receiving transmission data input via the transmission path 100,
It outputs the received value mti102b as well as the received transmission data. Then, the communication control means 112 sends a control signal 104 to the time data creation means 104, the storage data creation means 106, the storage means 108, and the data input/output means 114.
a, 106a, 108a.

114a is output at a predetermined timing. When the time data creation means 104 receives this control signal 104a,
The time data created at the timing when the control signal 104a is manually input is output to the storage data creation means 106, and the storage data creation means 106 sends the storage data created by adding the time data to the received transmission data to the storage means 108. Output. The storage means 108, which receives and stores the stored data, outputs the stored data to the data input/output means 114 when the control signal 108a is input, and the data input/output means 114 receives the control signal 114a. Decodes stored data and outputs a signal to an external circuit.

Furthermore, the communication control means 112 outputs a control signal 104a that instructs the time data creation means 104 to output time data at predetermined time intervals, and outputs a control signal 108a that instructs the storage means 108 to output stored data. At the same time, it outputs a control signal 110a instructing the comparing/determining means 110 to start determining the validity of the stored data. Then, the time data creation means 104 outputs the time data to the comparison and determination means 110, and the storage means 108 outputs the stored data to the comparison and determination means 110. The comparison/judgment means 110 that receives the time data and the stored data compares the stored time data with the time data currently output by the time data creation means 104 according to the control signal 110a to determine whether the stored data is outdated. The validity of the transmitted data is determined by determining whether the transmission data is present or not.

The transmitter of the communication device 110 connects an external circuit (specifically,
2) is input to the data input means 114, the data input/output means 114 forms data from the input information and outputs it to the transmission data creation means 116, and requests the start of transmission. data input signal 114
b is output to the communication control means 112. Communication control means 11
2 outputs control signals 116a and 120a to transmission data creation means 116 and carrier sense means 120, respectively, upon receiving this data input signal 114b.

Then, the transmission data creation means 116 creates transmission data based on the data input from the data input/output means 114 and outputs the transmission data to the transmission means 110. Start detecting the presence or absence of (signal). Here, the carrier sense means 120 outputs a sending permission signal 120b to the communication l1l- means 112 when no carrier is detected on the transmission line 100. The communication control means 112 receives this sending permission signal 1.
When receiving or receiving 20b, a control signal 11 instructs to start transmitting.
8a to the transmission means 118, and the transmission means 118 sends the transmission data inputted from the transmission data creation means 116 to the transmission path 100.

A block diagram showing the overall configuration of the data transmission system is shown in FIG. In FIG. 2, a plurality of overconfidence devices 10, 20, 30, 40°50.60 are connected to the transmission path 100, and each communication device has a plurality of overconfidence devices 10, 20, 30, 40°50.60. 10゜20.30.40.50.6
The configuration of communication device 0 is the same as the configuration of communication device 10 shown in FIG. The driver circuit 11゜21, which is an external circuit, is connected to the Tsushin @10.20, and the driver circuit 11.21 is included in the communication device 10.20. >210, 220 are formed, and a load 12.13 is connected to each C/U.In addition, the overconfidence device 30, 40, 50, 60 is connected to a sensor 31, 32, 33, which is an external circuit, respectively. and a switch 34. A specific example of this data transmission system is a steering/suspension control system formed within a vehicle.

This data transmission system is a power steering C/U that controls the power steering solenoid valve 12.
210, a suspension C/LJ 220 that controls the shock absorber actuator 22, a steering speed sensor 31 that detects the speed at which the driver turns the steering wheel, a vehicle speed sensor 41 that detects the speed of the vehicle, and a road surface on which the vehicle is traveling. A road surface condition sensor 51 that detects the condition of the vehicle using sound waves or the like and a select switch 61 are connected by multiplex communication. This power steering C
/lJ 210 and suspension C/U220 are:
Various sensors 31, 41, 51 and select switch 6
By sharing the information from 1 with each other, we can adjust the weight of the power steering and the stiffness of the shock absorber, achieving both ride comfort and steering stability. controlling the vehicle.

Next, the operation of this control system is shown in Figures 1 and 2.
This will be explained using figures.

1) Transmission operation: For example, when the driver turns the steering wheel, the steering speed sensor 31 detects the steering speed (speed at which the steering wheel is rotated) and transmits the steering speed signal to the communication device 3.
Output to 0. When this steering speed signal is input to the communication device 30, the data input/output means 114 forms data to be transmitted based on the steering speed signal and outputs a data input signal 114b. When the communication control means 112 receives the data input signal 114b, the communication control means 112 transmits the data to the transmission data creation means 116.
and outputs control signals 116a and 120a for performing a transmission operation to carrier sense means 120. Then, the transmission data creation means 116 creates transmission data in a format defined by the communication format from the data input from the data input/output means 114, and outputs it to the transmission means 118.
The carrier sense means 120 starts detecting the presence or absence of a carrier on the transmission path 100. Here, when the carrier sense means 120 detects that there is no carrier on the transmission path 100, it outputs a transmission permission signal 120b to the communication control means 112. Then, the communication control means 112 sends a control signal 118a to the transmission means 11 instructing to start sending out the transmission data.
8, and the transmission means 118 transmits the data to the transmission data creation means 1.
The transmission data input from 16 is asynchronously sent to the transmission line 100.

At this time, if another communication device, for example, communication device t40 simultaneously sends out transmission data having vehicle speed information at the same timing as the communication device 30 sends out the transmission data, the two transmission data will collide on the transmission path 100. This makes it impossible to send accurate transmission data. To prevent this, a data priority is determined for each piece of information to be transmitted, and when two or more pieces of transmitted data collide on the transmission path 100, each communication device that has sent the data compares the priorities and continues the transmission. There is a method in which the communication device that sent the transmission data with a higher priority continues the transmission, and the communication device that sent the transmission data with the lower priority stops the transmission and starts transmitting again from the beginning. Be taken. For example, vehicle speed information is set to have a lower data priority than road surface conditions and steering speed information, and is transmitted by the communication device 130 that has transmitted the transmission data of the steering speed information, which has a higher data priority. The communication device 40 that sent the transmission data of the vehicle speed information, which has a low data priority, stops transmitting, and the communication device H
After 30 transmissions are completed, transmission starts again.

2) Reception Operation 2 The transmission data transmitted by the communication device f30 in the above method is input to the communication device 5110.20 of the power steering C/U 210 and the suspension C/IJ 220, respectively, via the transmission path 100. Then, the transmission data is input to the receiving means 102,
The receiving means 102 determines whether or not to receive the input transmission data, and when receiving the transmission data, transmits the control signal 1.
02. b is output to the communication control means 112. Communication 111
When the means 112 receives the control signal 102b, it outputs a control signal 104a requesting the output of time data to the time data creation means 104, and also outputs the control signal 104a to the storage data creation means 106. Storage means 108 and data input/output means 11
a control signal 106a instructing to start operation to 4;
108a and 114a are output at predetermined timings. The time data creation means 104 constantly creates time data, and outputs the created time data to the storage data creation means 106 when it receives the control signal @104a.

(The time data used here may be of a relative scale that allows the context of time to be understood. Therefore, the timing at which the time data creation means 104 outputs the time data to be added to the transmission data is at a specific timing. Good to have,
For example, the timing may be the timing at which the reception of the header is confirmed, or the timing at which error checking of the received transmission data is completed. ) and storage data creation means 106
adds this time data to the received transmission data to form storage data and outputs it to storage means 108, and storage means 108 stores the input storage data. moreover,
When the storage means 108 receives the control signal @108a, it outputs it to the data input/output means 114.
outputs control signals for controlling the power steering solenoid valve 12 and the shock absorber actuator 22 to the drive circuits 11 and 21, respectively, based on the steering speed information obtained by decoding the input stored data. 11.12 is the power steering solenoid valve 12. Shock absorber actuator 22 is operated.

3) Validity judgment operation of stored data: In each communication device, the communication control means 112 performs Ii! at a predetermined time. A control II signal 104a that instructs to output current time data to the comparison/judgment means 110 at intervals, and a control l signal that instructs to output stored data to the storage means 108.
The ht a a number 110a outputs the signal 108a and instructs the comparison/judgment means 110 to start operation.
Output. The time data creation means 104 receives the control signal 1
The time data created when receiving 04a is output to the comparison and judgment means 110, and the storage means 108 outputs the stored data to the comparison and judgment means 110.

Then, the comparison/judgment means 110 determines that the time data creation means 1
The validity of the stored data is periodically determined by comparing the time data input from 04 with the stored time data. For example, the comparison/judgment means 110 of the communication device 10 of the power steering C/U 210 detects that the transmission data received from the communication device 130 is input from the time data creation means 104 because a certain period of time has passed since the reception. It is determined that the difference between the time data and the time data included in the stored data (transmission data received from the communication device 130) has become larger than a predetermined value, and the effectiveness of the stored data has decreased.

4) Data transmission request operation As described above, the comparison judgment means 110 of the communication device @10 of the power steering C/U 210
When the comparison judgment means 110 determines that the data transmission request signal 110b is determined, the comparison judgment means 110 outputs the data transmission request signal 110b to the communication control means 112. Then, in order to request the communication device 130 to send the transmission data, the communication control means 112 outputs a control signal 116a to the transmission data creation means 116, which instructs the formation of J transmission data that requests the transmission of transmission data. Then, the transmission data "requesting transmission of transmission data" created by the transmission data creation means 116 is transmitted to the communication device 30 using the transmission method shown in 1). In addition, if the transmission destination of the transmission data is, for example, the communication device 40 that transmits transmission data with a low data priority, "request transmission of r transmission data", "instruct to raise the data priority" ” information is added to the J transmission data requesting the transmission of transmission data and transmitted to the communication device 4o.

5) Communication abnormality detection operation: For example, the communication device 10 sends transmission data that “requests transmission of transmission data” to the communication device f30.
After transmitting the information to
If it is detected that the contents of the stored data stored in the 8 have not been updated, the communication mi control means 112 determines that a communication abnormality has occurred based on the output signal of the comparison and determination means 110, and issues an alarm. This will notify the user and switch the entire system to failsafe mode.

As explained above, each communication device of the data transmission system uses the time data creation means 10 for creating time data.
4, means 108 for adding and storing time data at the time of receiving the transmitted data to the received transmission data, and comparing the time data stored in the storage means 108 with the current time data. The configuration includes a comparison/determination means 110 for determining the validity of stored data. For this reason, the power steering C/LJ 210 and the suspension C/U 220 operate to request the transmission of transmission data when the validity of the stored data decreases after a certain period of time has passed since the transmission data was received. By performing an operation that instructs a change in data priority, it is possible to receive new transmission data and appropriately control the power steering solenoid valve 12 and shock absorber actuator 22 based on the newly received transmission data. becomes.

FIG. 3 shows another embodiment of the invention,
FIG. 2 is a block diagram showing the configuration of a receiving section of the communication device. The configuration of this embodiment is almost the same as the configuration of the receiving section shown in FIG. Instead of the comparison/judgment means 110 determining the validity of the transmitted data, the time data stored in the storage means 108 and the time data currently output by the time data creation means 104 are compared at predetermined intervals to determine the current data. A comparison and inference means 300 is used to infer data.

This embodiment performs a receiving operation similar to that of the communication device 210 shown in FIG. 1, and also infers current data from past stored data stored in the storage means 108. will be explained based on FIGS. 3 and 4. FIG. 4 is a diagram showing a data inference method.

A control signal instructing the communication control means 112 of the communication device to output the storage data stored in the storage means 108 to the comparison and inference means 300, and the time data creation means 10
4 and a control signal instructing to output the current time data to the comparison and inference means 300 at predetermined time intervals. Then, the comparison and inference means 300 compares the time data input from the time data creation means 104 and the time data stored in the storage means 108, and determines the validity of the stored data. Furthermore, as shown in FIG. 4, the current data (data 3.t3) is inferred from the two latest stored data (data 1.tl) and (data 2.t2). When the amount of information communicated in the system increases and the reception cycle of transmission data becomes longer than a predetermined time, this inference data is outputted to the outside via the data input/output means 114.

In this embodiment, the communication device of the data transmission system is provided with a means for inferring current data from received and stored past transmission data and time data. It becomes possible to perform more appropriate load control by inferring from past transmission data. Further, even when new transmission data cannot be received due to the occurrence of a communication abnormality, it is also possible to temporarily use inferred data.

〔Effect of the invention〕

As explained above based on specific examples,
The energizing device adds time data to the received transmission data and stores it, and determines the validity of the stored data based on a comparison between the current time data and the previously stored time data. For this reason, it is now possible to request the transmission of transmission data when it is determined that the validity of the stored data has decreased, or to perform data inference from the stored data. It becomes possible to perform appropriate control of the transmission system, and it becomes possible to solve the above-mentioned problems.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a communication device that is an embodiment of the present invention. FIG. 2 is a block diagram showing the overall configuration of a data transmission system of the present invention. FIG. 4 is a block diagram showing the configuration of a receiving section of a communication device according to another embodiment. FIG. 4 is a diagram showing the data inference method of the present invention. FIG. 5 is a conventional diagram. 100...Transmission line, 10.20.30. ．． 40°50
．． 60...Communication device, 11.21-...Drive circuit, 1
2.22,520...Load, 31,41.51...
Sensor, 61... Switch, 102, 501... Receiving means, 104... Time data creation means, 106.
. . . Memory data creation means, 108, 502 . . . Storage means, 110 . ...Transmission data creation means, 120...
・Career sense means, 210.220...C/U,
300--Comparison and inference means, 500--Reception unit of communication device, 503--Data output means, 504--Reception control means, 510--Load drive circuit. Patent applicant: Nissan Motor Co., Ltd.

Claims (1)

[Claims] In a data transmission system in which a plurality of communication devices communicate transmission data via a common transmission path, a receiving unit of the communication device includes a receiving unit that receives transmission data from the transmission path, and creates time data. Time data creation means;
storage data creation means for adding the time data to the transmission data to form storage data; storage means for storing the storage data; 1. A data transmission system comprising: comparison and judgment means that compares the stored data with time data at predetermined time intervals and judges the validity of the stored data based on the comparison results.