JPS61237554A - Multiplex transmission equipment - Google Patents

Abstract

PURPOSE:To simplify the circuit by making the primary station connected in loop to plural secondary stations issue polling signal and data signal and making the secondary station receive that data only when it is polled then polle the low-order station. CONSTITUTION:Plural number of secondary stations 2-5 are connected in loop to a primary station 1 by two-core transmission line 6. The primary station outputs polling signal from its output terminal 1-0, and then sends out data signal sequentially. The secondary station 2 takes in the poling signal, and if it is designated, it receives the data signal. If it is not designated, it transfers the polling signal and data sent from the high-order station to the low-order station. In such a way, the multiplex transmission is executed by a simple circuit.

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention is constructed by connecting a primary station (master station) and a plurality of secondary stations (slave stations) in a digital chain manner using a dedicated two-core wire. This invention relates to a multiplex transmission device.

[Summary of the invention]

The multiplex transmission device according to the present invention includes a primary station that sends out a data signal to each secondary station at predetermined intervals after sending out a polling signal, and a continuous loop connection to the primary station in a digital chain manner, from the priority station to the primary station. A plurality of secondary stations are provided which receive data by receiving a polling signal and send out a polling signal. Such a configuration eliminates the need to set addresses for each secondary station, making it possible to easily install the secondary stations.

(Prior art and its problems) In general, in a multiplex transmission device that configures a data transmission system by connecting a primary station and a plurality of secondary stations using a two-core dedicated line, arbitrary A multi-drop method is often used in which a secondary station is connected to the
It is necessary to set a unique address for each next station. Such address settings are usually done using the DIP installed at each secondary station.
It is set by a switch etc.

However, when it is necessary to make the secondary station extremely compact, there is a problem in that the DIP switch limits the miniaturization. Furthermore, when setting up a large number of secondary stations at once, setting addresses is relatively easy, but when increasing or decreasing the number of secondary stations after configuring the multiplex transmission equipment system, the addresses may not be consecutive. Furthermore, there is a possibility that a plurality of secondary stations may be set to the same address by mistake, resulting in a transmission error. A shift register method is also known in which the address is not specified for each secondary station number in order to facilitate work at the installation site of the secondary station, but in this method, in addition to data signals, signal lines for clock signals are There was a problem in that the transmission system could not be configured using the necessary and inexpensive two-core wire, and the price of the transmission cable increased.

[Purpose of the invention]

The present invention has been made in view of the problems of the conventional multiplex transmission device, and uses DIP switches to
It is an object of the present invention to provide a multiplex transmission device that does not require setting an address to the next station and can configure a system using a two-core transmission cable.

[Structure and effects of the invention]

The present invention is a multiplex transmission device in which a primary station and a plurality of secondary stations are loop-connected in a digital chain manner via a transmission line, and the primary station transmits a polling signal, which is the right to transmit and receive, to the secondary station having the highest priority. It has a polling signal sending means for sending out a polling signal to a station, and a data sending means for sequentially and intermittently sending data to each secondary station after sending out a polling signal, and each secondary station is connected between an input terminal and an output terminal. a filter means for passing a data signal obtained by the receiving means and blocking a polling signal; a receiving means for receiving a data signal given after receiving the polling signal; and a filter means for receiving a data signal given after receiving the polling signal; The present invention is characterized in that it has a polling signal sending means for sending out a polling signal.

According to the present invention having such features, a two-core transmission line is used to transmit a polling signal and a data signal, and each secondary station transmits the data after receiving the polling signal that is the transmission/reception right to its own station. Receive as data for. After receiving the data, the polling signal is sequentially transmitted to the subsequent secondary stations. Such a configuration makes it possible to transmit data to each secondary station using only two-core transmission lines. In addition, since addresses are not set for each secondary station, there is no need to provide a DIP switch (therefore, each secondary station can be made smaller and workability when installing the secondary station is improved). becomes possible.

[Explanation of Examples]

FIG. 1 is a schematic block diagram showing an embodiment of a multiplex transmission apparatus according to the present invention. In this figure, primary station 1 and multiple 2
The next stations 2, 3, 4.5 are loop-connected in a digital chain by a two-core transmission line 6. That is, the output terminals 1-0 of the primary station 1 are the input terminals 2 of the secondary station 2 connected in the highest order.
-i, and the output terminal 2-o of the secondary station 2 is connected to the transmission line 6
is connected to the input terminal 3-i of the next secondary station 30. Similarly, the output terminal 3-o of the secondary station 3 is connected to the output terminal 3-o of the secondary station 4.
The output terminal 4-o is connected to the input terminal 4-i of the secondary station 5, and the output terminal 5-o of the secondary station 5 in the last order is connected to the input terminal 4-i of the Next station 1 input terminal 1-
Connected to 4. The primary station 1 transmits a boring signal that transmits a data signal to a secondary station connected in a loop, and data that transmits to a secondary station 2, 3.4.5, intermittently and sequentially at predetermined time intervals. .

(Configuration of Primary Station) As shown in FIG. 2, the configuration of the primary station 1 includes a polling signal transmission circuit 11 that operates based on an external start signal, a data signal counter 12 that is reset by the start signal, It has a data signal timer 13 and a count display 14.

The polling signal transmitting circuit 11 is supplied with the output of an oscillator 15 that oscillates a frequency of a polling signal, for example, IMHz, and transmits a polling signal in response to a start signal and determines the timing of the polling signal from the data signal transmitting circuit 1.
6.

The data signal transmitting circuit 16 is a transmitting circuit that sequentially transmits data for each secondary station set from the outside using, for example, a 60 KHz NRZ code, and the data signal timer 13 is reset for each transmission.

The data signal timer 13 is a timer that has a timer time T and sets the sending timing of the data signal, and transmits a time-up signal to the data signal transmitting circuit 16 every time the time is up, and based on the time-up signal, the data signal transmitting circuit 16 Send data to the next station sequentially. The time-up output of the data signal timer 13 is also applied to the data signal counter 12 as a counting input. Data signal counter 12
holds the address of the secondary station transmitting data by sequentially counting the signals. The count value is then displayed on the count display 14. Again 1
The input terminal 1-i of the next station 1 is the polling signal detection circuit 17
can be conveyed to. The polling signal detection circuit 17 receives a polling signal from the last secondary station 5 and provides a clear signal to the data signal timer 13 and count display 14.

(Configuration of Secondary Station) FIG. 3 is a block diagram showing the configuration of the secondary station 2, and the other secondary stations 3 to 5 have similar configurations. Now, a low-pass filter 21 is connected to the input terminal 2-i of the secondary station 2.
The polling signal receiving circuit 22 is connected to the polling signal receiving circuit 22. The low-pass filter 21 is a passive filter consisting of an LC, and is used as a polling signal regardless of the power state.
This is a filter that blocks the signal of the frequency MH2 and transmits the data signal modulated at a frequency lower than IMHz, for example, 60 KHz, which is transmitted from the transmission line 6, to the output terminal 2-o as it is. Also, the polling signal receiving circuit 22 is connected to the transmission line 6.
It receives the polling signal given through the circuit and gives its output to the data signal receiving circuit 23. The data signal receiving circuit 23 receives the data signal immediately after the polling signal is received, and provides its output to the data signal reproducing circuit 24 and the polling signal transmitting circuit 25. The data signal reproducing circuit 24 decodes the data signal sent from the primary station 1 and outputs it as a data output, and the output is used as a drive signal for different output means, such as a relay, for each secondary station. It will be done. The polling signal transmitting circuit 25 is a transmitting circuit that oscillates a polling signal in the secondary station 2 itself and sends the polling signal to the subsequent secondary station, and the IMHz frequency used to generate the polling signal is
An oscillator 26 is connected thereto. The outputs of the low-pass filter 21 and the polling signal transmission circuit 25 are connected to the subsequent secondary station 3 via the output terminal 2-0.

(Operation of this embodiment) Next, the operation of this embodiment will be described with reference to flowcharts and waveform diagrams. FIG. 4 is a flowchart showing the operation of the primary station 1, and FIGS. In the figure, when a start signal is given to the primary station 1, the operation starts, and the process first proceeds to step 31 in FIG. 4, where the data signal counter 12 and data signal timer 13 are reset.

Then, in step 32, the polling signal transmitting circuit 1
1 to 5 (al), the polling signal P1 is sent out. As mentioned above, as the polling signal, a signal with a frequency of IMHz is sent out for a predetermined period of time. Then, the process proceeds to step 33, where the data signal transmission circuit 16
As shown in FIG. 5(a), the data signal D2 is sent to the secondary station 2. After sending the data signal step 34
Then, the data signal timer 13 is operated. Next, in step 35, the data signal counter 12 is incremented. Then, the data signal counter 12 will indicate the address of the secondary station currently sending data,
The value is displayed by the count display 14.

Now, if the polling signal P1 and the data signal D2 are given, the secondary station 2 receives the polling signal P1 by the polling signal receiving circuit 22, and then receives the data signal D2 for the secondary station 2 by the data signal receiving circuit 23. . The data D2 is then reproduced by the data reproducing circuit 24 to perform a predetermined operation. After receiving the data, the polling signal transmission circuit 25 sends a new polling signal P2.
is generated and sent from the output terminal 2-0 as shown in FIG. 5(b). The data signal D2 is shown in FIGS. 5(a) to (e).
As shown in the figure, the data passes through the low-pass filters of each of the secondary stations 2 to 5 and returns to the primary station 1, but the data is valid only for the secondary station 2 to which the polling signal P1 is applied. After incrementing the data signal counter 12 in step 35, the primary station 1 proceeds to step 36 and checks whether a polling signal is received. If the polling signal is not received from the input terminal 1-i, the primary station 1 proceeds to step 37. It is checked whether the data signal timer 13 having the above-mentioned time T times out. If the time is up, the process returns to step 33 and the data signal counter 12
The data signal D for the next secondary station indicated by , that is, secondary station 3
3 is sent out as shown in FIG. 5(a).

Then, the secondary station 3 receives the polling signal P from the secondary station 2.
After that, the data signal D3 for the secondary station 3 is received. Therefore, the data signal D3 becomes valid data for the secondary station 3, and then the polling signal P3 is sent to the secondary station 4 in the same manner. Primary station 1
Similarly, in step 35, the data signal counter 12 is incremented, and upon waiting for the time-up of the data signal tie 713, the data signal D4 to the secondary station 4 is incremented.
Send out. This data signal passes through the low-pass filters of the secondary stations 2 and 3, respectively, and is transmitted to the secondary station 4. Similarly, the secondary station 5 also receives the polling signal P4 and data signal D5 from the secondary station 4, and then sends out the polling signal P5 and transmits it to the primary station 1 via the transmission line 6. Then, the polling signal detection circuit 17 detects this signal P5, so the process proceeds to step 3 via step 36, and the data signal counter 1 at that time is
The count value of 2 is displayed and the process returns to step 31. Thus 1
After completing the data transmission cycle, a polling signal P1 is transmitted in step 32, and this operation is repeated in the same manner thereafter.

In this way, the primary station l transmits the polling signal and then sequentially transmits data for each secondary station at a predetermined timing, so that the polling signal generated at each secondary station is superimposed between them. Data transmission can be performed without setting addresses for each secondary station.

In this embodiment, a multiplex transmission apparatus using four secondary stations has been described, but it goes without saying that a similar system can be constructed using an even larger number of secondary stations. Furthermore, in this embodiment, a low-pass filter is provided in each secondary station to pass the data signal as is and block only the polling signal. However, by using a low frequency signal as the polling signal and modulating the data signal with a high frequency, It is also possible to change the filter that only passes signals to a filter such as a bypass filter.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing an embodiment of a multiplex transmission device according to the present invention, and FIG. 2 is a schematic block diagram showing an embodiment of a multiplex transmission device according to the present invention.
FIG. 3 is a block diagram showing the configuration of the secondary station 1, FIG. 4 is a flowchart showing the operation of the primary station 1, and FIG. 5 shows each part of the transmission line of the multiplex transmission equipment. a
1--Primary station 2, 3.4.5--Secondary station 6--Transmission line 11--Polling Signal transmission circuit 12---Data signal counter
13-・-・-・Data signal timer 16-・-・
- Data signal transmission circuit 17- - Polling signal detection circuit 21 - - Low pass filter 22 - Polling signal reception circuit 23 -
Row 11 Data signal receiving circuit 24 --- Data signal reproducing circuit 25 --- Polling signal transmitting circuit Patent applicant Tateishi Electric Co., Ltd. Agent Patent attorney Yoshiki Okamoto (and one other person) Figure 3 Figure 5 Figure (e' D2 D3 D4 D5 Figure 4 Proceedings Amendment (spontaneous) June 17, 1985 1. Indication of the case 1985 Patent Application No. 078947 2. Name of the invention Name of multiplex transmission device Name ( 294) Tateishi Electric Co., Ltd. Representative: Takao Takao 4, Agent address: 550, 3rd floor, Shinkosan Building, 1-13-38 Nishihonmachi, Nishi-ku, Osaka, Osaka Prefecture, Detailed description of the invention in the specification subject to amendment Column 6, Contents of amendment (1) r60KHz on page 7, lines 15 to 16 of the specification
The description of "NRZ code" will be corrected to "r60KHz and 30KHz bi-phase code". (2) Change the description of r60KHzJ on page 9, line 4 of the specification to r
Corrected to 60KIIz and 30 KHz J. that's all

Claims (2)

[Claims] (1) A multiplex transmission device in which a primary station and a plurality of secondary stations are loop-connected in a digital chain manner via a transmission line, and the primary station transmits a polling signal, which is the right to transmit and receive, to the two stations with the highest priority. a polling signal transmitting means for transmitting a polling signal to the next station; and a data transmitting means for sequentially and intermittently transmitting data to each of the secondary stations after the polling signal transmitting means transmits the re-polling signal;
Each of the secondary stations has: filter means connected between the input and output terminals to pass the data signal obtained from the input terminal and block the polling signal; and receiving means to receive the data signal given after receiving the polling signal. A multiplex transmission apparatus comprising: a polling signal transmitting means for transmitting a polling signal after the receiving means receives the data signal and before the primary station transmits the data. (2) The polling signal sent by the polling signal sending means of the primary station and each of the secondary stations is a signal having a higher frequency than the data signal, and the filter means of each of the secondary stations blocks the polling signal. 2. The multiplex transmission device according to claim 1, wherein the multiplex transmission device is a low-pass filter that passes only a data signal.