JPH054357Y2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field The present invention relates to a loop data transmission device that allows each station to determine abnormalities in other stations.

(2) Prior Art Conventionally, a loop data transmission method is known in which data is transmitted sequentially between a plurality of stations, and there is a method shown in FIG. 1. In the figure, 1, 2, 3, and 4 are different stations, which are connected by a data transmission line 10, and each station has terminal devices 110, 210,
310 and 410 are connected. Information from the terminal devices is sequentially transmitted between each station in the direction of the arrow. The information transmitted is in the form of frame data, and FIG. 2 represents cyclic frame data. Each frame data is composed of, for example, three data slots SL0, SL1, SL2,
As shown in Figure 3, each data slot has a start bit ST at the beginning, a stop bit SP at the end, and
Data bits that store information data between them
It is composed of D ₀ to D ₇ .

In the above transmission system, the stations operate asynchronously, but each station operates at a timing such that while one station outputs one data slot, one data slot is input from the upstream station. At each station, a processor reads and processes data from the upstream station, outputs a control signal to its own terminal device, and also reads information from its own terminal device and rewrites the data slot to the downstream station via the signal transmission path. Output to station. When the processor of each station is operating normally, it outputs pulses within a predetermined period, and when the internal abnormality detection circuit has a pulse period within a predetermined period, it outputs data to the processor. After passing through the pulse, the pulse is outputted from the station, and when the pulse period is no longer within a predetermined period, the station is bypassed. If a station is abnormal, an abnormality alarm device provided for each station is activated to generate an alarm.

In this way, when a station is abnormal, the cyclic data is bypassed by that abnormal station, so other normal stations cannot determine which station is abnormal.
An alarm for station abnormality is issued only from each abnormal station, and an abnormality alarm device is required for each station. For example, in a car where it is convenient to notify the driver of abnormalities in each station by concentrating them in one place on the instrument, it is necessary to run signal lines from each station to the instrument, so it is necessary to multiplex the signal lines and connect them to the harness. The benefits of reducing this will be reduced.

(3) Purpose and structure of the invention The present invention has been made in view of the above points, and is a loop type data transmission device that transmits cyclic frame data between a plurality of stations connected in a loop through a data transmission path. ,
The purpose is to propose a data transmission method that allows each station to determine abnormalities in other stations.To this end, the frame data has an abnormality determination slot consisting of a bit area for determining abnormalities in each station. Each station has an abnormality detecting means for detecting an abnormality in the station, a bypass means for passing the frame data as is when an abnormality is detected by the abnormality detecting means, and an abnormality is detected by the abnormality detecting means. If not, the transmitting means inverts and transmits the value of the bit area corresponding to the station in the bit area of the abnormality determination slot in the received frame data, and the predetermined station among the stations further includes: A storage means for storing the value of each bit area of the abnormality determination slot in the received frame data, and a storage means for storing the value of each bit area of the abnormality determination slot in the currently received frame data and each bit received last time and stored in the storage means. The present invention is provided with a comparison means for comparing the values of the regions and a display means for displaying an abnormality in the station corresponding to the bit region that matches as a result of the comparison by the comparison means.

(4) Examples The present invention will be explained below based on the drawings.

FIG. 4 shows the cyclic data used in the data transmission device according to the present invention, in which control data slots SL0, SL1,
In addition to SL2, an abnormality determination slot SL3 is provided. As shown in FIG _. 5, the abnormality determination slot SL3 consists of a start bit ST at the beginning, a stop bit SP at the end, and data bits D ₀ to D ₇ between them.
D ₁ , D ₂ , and D ₃ are determination bits for determining abnormalities in stations 1, 2, 3, and 4, respectively.

FIG. 6 shows the configuration of one example of the station of the data transmission device according to the present invention, and in the case of a vehicle, it is installed at or near the instrument. In the figure, 101 is a processor that controls the operation of the station. The processor 101 reads data transmitted from the station via the signal transmission path 10, performs predetermined processing based on the data, Outputs control signals to the terminal device 110 via the interface 102 and I/Os information from the terminal device 110
The data is read through the interface 102 and the data slot is rewritten based on the signal transmission line 1.
0 to the downstream station.

On the other hand, the processor 101 outputs a pulse signal to indicate whether or not it is operating normally. When the processor 101 is operating normally, the period of the pulse signal is less than or equal to a predetermined period. In the case of abnormal operation, the pulse period becomes a predetermined value or more.

Reference numeral 103 denotes an abnormality detection circuit as an abnormality detection means for detecting an abnormality in the station based on the period of the pulse signal output from the processor 101 via the I/O interface 102;
is a transmission line changeover switch as a bypass means that is switched by the output of the abnormality detection circuit 103. When the station is normal, it is in the position shown by the solid line and inputs the cyclic data transmitted from the outside to the processor 1, but the abnormality detection circuit When an abnormality in the station is detected by 103, it is switched to the position shown by the broken line, and the cyclic data is not input to the processor 1 and is bypassed. 500 is a centralized abnormality warning device that is installed only at the central station (in a vehicle, it is installed at or near the instrument) among multiple stations;
It is connected to the I/O interface 102.

The configurations of the other stations included in the data transmission device are the same as the configuration of station 1 described above, except for the centralized abnormality warning device.

Next, the operation of the data transmission device will be explained based on the flowchart of FIG.

Data bits D ₀ to _{D 3} of abnormality determination slot SL3
are inverted and output as "0" and "1" for each frame by stations 1 to 4, respectively.

The processor 101 reads data transmitted via the transmission path 10 from the upstream station (P-1), performs predetermined processing based on the data (P-2), and
A control signal is output to the terminal device 110 via (P-3). On the other hand, the processor 101 transfers information from the terminal device 110 to the I/O interface 10.
2 (P-4), and performs the following series of transmission data processing (P-5). That is,
Writes the information read from the terminal device 110 into a predetermined corresponding slot (either SL0, SL1, or SL2) (P-51), checks the slot number to be output in this routine (P-52), If the result is “3” (P-53) step (P-54)
Then, as the output data of the abnormality determination slot SL3, only one bit among bits _D0 to _D3 (which bit depends on the station and the correspondence is shown in Fig. 5) is set to a value that is inverted from the previous frame. The other bits are set to the most recently read value of SL3 (P-55). After that, it is output as transmission data.

By programming the processor as described above, bit _D0 of error detection slot SL3
~D ₃ inverts “0” and “1” every frame,
It is transmitted to any station. Therefore, for example, if station 2 becomes abnormal and data is bypassed, bit _D1 of abnormality determination slot SL3 is fixed at a constant value and transmitted as shown in FIG.

Next, it is determined which station is abnormal and data is being bypassed, as shown in the flow chart shown in FIG. The process (P-2') shown in FIG. 9 is a detailed representation of the read data process (P-2) shown in FIG. This is because steps (P-22) to (P-26) have been added between P-3). Note that this process (P-2)' is added only to the central station 1.

Therefore, to explain the process shown in FIG. 9, in step (P-1) data from the transmission path is read,
In step (P-21), the read data is stored in a predetermined memory. In step (P-22), the slot number of the read data is checked, and if it is judged as "SL3" in step (P-23), the process advances to step (P-24) and the slot number of the data read this time is checked.
Exclusive OR is performed between the data of SL3 and the data of SL3 of the previous frame. In step (P-25), all bits of D ₀ to _{D 3} are set to “1” as a result.
If there is a “0” bit, it is determined that there is an abnormal station and the step (P
-26), the abnormal station is determined based on the bit for which the exclusive OR result is "0", and data indicating this is output to the I/O interface 102.

When the station 1 itself is abnormal, the above method cannot issue an alarm, so the output of the abnormality detection circuit 103 is directly input to the centralized alarm device 500 to issue an alarm in the same way as other stations. The reason why the bit _D0 for determining an abnormality in station 1 is provided in abnormality determination slot SL3 is to provide flexibility so that it can be used even if the centralized abnormality alarm device 500 is attached to any station other than station 1. It's for a reason.

(6) Effects of the invention As explained above, in the invention, each frame data to be transmitted has an abnormality determination slot consisting of a bit area for determining the abnormality of each station. , an abnormality detection means for detecting an abnormality in the station; a bypass means for passing the frame data as is when an abnormality is detected by the abnormality detection means; and a bypass means for passing the frame data as is when the abnormality detection means detects an abnormality; a transmission means for inverting and transmitting the value of the bit area corresponding to the station in question among the bit areas of the abnormality determination slot in the station; A storage means for storing the values of each bit area of the slot compares the value of each bit area of the abnormality determination slot in the frame data received this time with the value of each bit area received last time and stored in the storage means. Since the comparison means and the display means for displaying the abnormality of the station corresponding to the matching bit area as a result of the comparison by the comparison means are provided, it is possible to prevent transmission data from bypassing the abnormal station due to an abnormality of the station. If the problem occurs, other stations can easily determine where the abnormal station is based on the transmitted data. Therefore, the determination of normality or abnormality of all stations in the system and the abnormality alarm display can be performed at one station. Therefore, there is no need to issue an abnormality alarm for each station, which simplifies the circuit configuration and enables centralized management. As a result, in a vehicle, only one driver can manage the signal lines at or near the instrument station without running signal lines from each station, which is convenient for driving.

[Brief explanation of the drawing]

Figure 1 is a diagram of a conventional loop data transmission system, Figure 2 is a data format used in the conventional loop data transmission system shown in Figure 1, and Figure 3 is a diagram of the data format shown in Figure 2. FIG. 4 is a detailed diagram of the data slot used in the loop data transmission device according to the present invention, FIG. 5 is a detailed diagram of the abnormality determination slot of the data format shown in FIG. 4, and FIG. FIG. 7 is a flowchart showing the operation of the data transmission system according to the invention; FIG. 8 is a diagram showing bit changes in slot data to explain the operation of the data transmission system according to the invention. FIG. 9 is a flowchart of the station abnormality determination operation of the data transmission device according to the present invention. 1, 2, 3, 4... Station, 10... Signal transmission line, 110, 210, 310, 410...
Terminal device, 101... Processor, 102...
I/O interface, 103... Abnormality detection circuit, 500... Centralized abnormality alarm device.

Claims (1)

[Claims for Utility Model Registration] In a loop data transmission device that transmits frame data consisting of binarized data in a predetermined direction between a plurality of stations connected in a loop through a data transmission path, the above frame data is , has an abnormality determination slot consisting of a bit area for determining an abnormality in each of the stations, and each of the stations has an abnormality detecting means for detecting an abnormality in the station, and an abnormality detecting means for detecting an abnormality in the station. case,
a bypass means for passing the frame data as is; and a transmission means for inverting and transmitting the value of the bit area corresponding to the station in question among the bit areas of the abnormality determination slot in the received frame data when no abnormality is detected by the abnormality detection means. Among the above-mentioned stations, a predetermined station further has storage means for storing the value of each bit area of the abnormality determination slot in the received frame data, and storage means for storing the value of each bit area of the abnormality determination slot in the currently received data frame. a comparison means for comparing the value of the bit area with the value of each bit area previously received and stored in the storage means; 1. A loop data transmission device, comprising: display means for displaying information.