JPS58182344A - Data transmission system - Google Patents

Abstract

PURPOSE:To obtain a simple data transmission system with less transmission loss time, by providing a simple pulse train to all slave stations connected to a master station, in transmitting data of the plural slave stations to the master station cyclicly. CONSTITUTION:A timing signal generated from a pattern pulse generator 2 installed in the master station 1 is transmitted to all the slave stations through a timing transmission line 6 from a timing signal output terminal 5 of the master station 1 with a master station line driver 4 at all times. The said timing signal denotes TF (second) by one frame and is a periodic pulse train consisting of a pulse period Tp having a pulse train continuously generating a pulse, where one pulse period is to (second), and of a space time Ts (second) corresponding to a period generating no pulse in one frame. Each slave station receives the timing signal with a line receiver through the timing signal input terminal.

Description

[Detailed description of the invention] F from Kono! AI/i relates to a communication method in which information from a plurality of slave stations distributed in a multi-drop connection is cyclically transmitted to a similarly connected master station.

In the conventional communication method, when configuring a data collection system using a multi-drop connection as shown in FIG. When transmitting to the master station,
As a method of specifying the transmission timing between each slave station,
By assigning address data to each slave station, the master station 1 and slave station 1a
~Slave stations Na communicate with each other and each slave station's data 1a
'~N a'k were collected. However, when it is necessary to collect data from each slave station in a cyclical manner, it is necessary to use a complicated polling sequence for the communication even though the transmission sequence of each slave station is constant. It is ideal for cyclical data transmission and collection, as there is a large communication time loss, that is, data transmission time loss, due to the use of a polling sequence.

It was not an effective method of communication.

This invention has been made in view of the above circumstances, and is useful when data from a plurality of slave stations distributed in a multi-drop connection is cyclically transmitted to a similarly connected master station. By giving a simple pulse train from the master station to all the slave stations, a data transmission method is provided which is a simpler system than the conventional method and has less transmission time loss. The explanation will be based on the description in the drawings.

In FIG. 2, slave stations 1a to Na are devices that collect data 1a' to data Na' and transmit them to master station 1, and master station 1 is a device that collects data 1a' to data Na' and transmits them to master station 1. This is a device that collects and reproduces data, and performs display and control based on that data. The master station 1 and the slave stations 1a to Na are all multi-drop connected to a data signal transmission line 20 and a timing transmission line 6. Next, based on FIG. 2 and FIG. The generated timing signal is
The master station driver 4 constantly sends a timing signal h from the master station I output terminal 5 to all the slave stations through the timing transmission line 6. As shown in FIG. 3, the timing signal has a pulse train in which TF [seconds] is one frame, and pulses with a pulse period of tOC seconds are continuously generated during one frame. Pulse period Tp [
The 06 slave station receives a timing signal from the line Resino<ENC through the timing signal input terminal 7, which is a periodic pulse train composed of the period Ts [seconds] and the period during which pulses are not generated. The received timing signal is sent to a programmable counter 9 and a timing frame discrimination circuit 10. The programmable counter has a pulse counting function that is set and reset during one frame TF (seconds) of the 9-digit timing signal, and pulses are counted from the first pulse generation point P in one frame of the sequentially sent timing signal. The number of counters is started, and the counter is set to reset at reset time Q. On the other hand, the timing signal g*'A
The discrimination circuit 10 is provided to determine the reset time Q, and the one pulse period to [seconds]
and space time TsC seconds], the final pulse 11 within the pulse period Tp [seconds] configured in the one frame, during the reset determination time tn, which has the relationship to<tn<Ts - (a) with respect to the space time TsC seconds]. The frame synchronization signal (timing frame signal in FIG. 3) of the timing signal generated at a time delayed from the final change point Q1 is used as a reset signal, and the reset signal is sent to the programmable counter 9 to reset the programmable counter 9. It is designed to reset the pulse count. Here, the time point when the frame synchronization signal of the timing signal is not generated is Q
By doing so, the 0 programmable counter 9 whose reset time is also Q is set to 'Fm'L at the timing position selection switch 12 at the -no-j, and when it counts the pulse selected by the selection switch 12, the timing controller 13 Send trigger signal to 14
It is designed to output . In FIG. 3, it is assumed that the number of slave stations is three, and the switch position of the timing position selection switch 12 of slave station 1a is set to the first pulse, slave station 2.
It is assumed that the switch a (51) is set to the 8th pulse and the switch position of the slave station 3a is set to the 15th pulse count. Transmission trigger signal 14ff: 13 data input to the timing controller of each received slave station A command is given to the shift register 15, which has a parallel-to-serial conversion circuit that serially converts data input in parallel from the terminal 30, to output data.The shift register 15 receives the command and converts the data into one block capable of asynchronous serial transmission. - is sent to the phase encoder 16, and the phase encoder 16
Phase encode pulse signal 1 for tc [seconds]
7 and transmits it to the line driver 18 as a data block. Line trino (18#-t) receiving phase encode pulse signal 17 as data block
The data block is controlled by a transmission control signal sent from the timing controller 13 and transmitted to the data transmission path 20 through the data output terminal 19.In addition, the clock generator 21 in FIG. The timing controller 13. and the timing controller 13. It measures the time adjustment between the shift register 15 and the phase encoder 16.

As described above, data blocks are transmitted to the data transmission path 20, and here, on the data transmission path 2o, the generation timings of the transmission trigger signals 14 within each slave station are temporally adjacent. In order to avoid data blocks of two slave stations colliding, the phase encode pulse signal '4tc (seconds), the data transmission delay time tv [seconds] from the slave station to the master station, and the generation of the transmission trigger signal I4. The relationship tc+tV4tW-(o) is required between the interval tw [seconds] between the transmission trigger signals 14a and 14b of two slave stations whose timings are adjacent in time.In FIG. 1a,
Of the slave stations 2a and 3a, slave stations 1a and 2as slave stations 2
It is clear that the generation timings of the transmission trigger signals 14 of the slave station 1a and the slave station 3a are temporally adjacent to each other, and the first pulse of the timing signal, which is the generation timing of the transmission trigger signal 14a of the slave station 1a, similarly Of the 8th pulse in the slave station 2aK and the 15th pulse in the slave station 3a, the interval between the 1st and 8th pulses and the interval between the 8th and 15th pulses are tw (seconds).As described above, Based on the timing signal, each slave station can sequentially send the phase encode pulse signal 917 onto the data transmission path 20 without collision between data blocks. Through the terminal 21, the master station receiver 22 receives the phase encode pulse signal 17 sent from each slave station. Data 7” lock ffjfJ space period tUC seconds] and timing signal space period ts (seconds) between the last slave station data block in one frame and the first slave station data block in the next frame The pulse train is formed as a pulse train sandwiching the pulse train.
The space time between the first data block 17a of a and the first data block 17b of the slave station 2a, or the space time between the data block 17b and the first data block 17ci of the slave station 3a [space time tu [seconds], or the space time 17c
and the space time ts (seconds) between data blocks 17d of the next 7 frames of slave station 1a.Master station line receiver 2
The pulse train received by h2 is rearranged in parallel by a master station shift register 23 having a serial-to-parallel conversion circuit, and is sent to a data pulse differential quantity f%824, which is a necessary part of a discriminator circuit through which it passes thereafter. After creating a differentiated waveform between ++ and I1 according to , the data shift clock in the data block is determined by the data shift clock discrimination circuit 25p, and by sending this to the master station soft register 23, the master station soft register After shifting within the data block 231'i according to the commanded data shift clock, the data is sent to the data latch 26 in parallel for each block. The differentiated waveform by the data pulse microchannel 24 is also sent to a frame clock discrimination circuit 27, and the frame clock discrimination circuit 27 uses the transmission trigger signal 14 to differentiate data from two temporally adjacent slave stations. For the inter-block space time tu [seconds] and the space time ts (seconds) between the data block of the most remote slave station in one frame of the timing signal and the data block of the first slave station in the next frame, ttl By determining the frame clock determination time tm [seconds] which has the relationship of <tm to ts - (c), tml from the last pulse change time P in the data block of the last slave station in one frame:
Seconds] The clock rises at the delayed time point P3, and the first pulse change of the first data block of the next frame occurs at the time Q.
A frame synchronization signal 28 having a period of TF (seconds) falling at Based on the absolute time position relationship, the address information of the data block, which indicates which slave station the pulse train of each data block is from, is automatically determined.In this way,
As is clear from the explanation of 0 or more, the data block that has been separated from the data of which slave station is output from the driver 29 through the side output terminal 31 for display number control, etc.
According to this invention, by giving a timing signal, which is a simple pulse train, to all slave stations, all slave stations can be easily handled without using address information or special command codes for data signals that were conventionally required. The master station can collect slave station data cyclically in frame units TF [seconds],
If it is introduced into a monitoring/control system that requires the master station to constantly collect information about slave stations, it can have a very large effect.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional data transmission method, FIG. 2 is a schematic diagram of a data transmission method according to the present invention, and FIG. 3 is a schematic diagram of a conventional data transmission method.
A time chart from timing signal generation at the master station to reproduction of slave station data to the master station. Figure 4 is also a block diagram of the master station, timing transmission path and data transmission path, and Figure 5 is a diagram showing multiple slave stations. A block diagram, timing transmission path, and data transmission path of any one of the slave stations. 1... Master station, 1a-Na... Slave station, 6... Timing transmission line, 20... Data transmission line.

Claims (1)

[Claims] 1. A communication method for cyclically transmitting information of a plurality of slave stations connected by a multi-drop connection to a master station also connected by a multi-drop connection,
A data transmission method 0 characterized in that address information of each slave station is automatically determined based on the timing signal by giving a timing signal having a simple sequence of <117 to all slave stations.