JPS59188257A - Signal transmission system - Google Patents

Abstract

PURPOSE:To perform two-way signal transmission in the same time zone by connecting respective information devices to one common transmission line in parallel through signal transmitters respectively, and allowing them to perform transmitting/receiving operation in synchronizing with the respective signal transmitters. CONSTITUTION:The signal transmitters 6 (6a-6h) have a transmitting/receiving function and are connected to one transmission line 7. Each transmitter 6 has a receiving circuit 61 and a transmitting circuit 63 and transmits and receives pieces of information D1 and DK to and from a process equipment 5 and a process source 4 through an output circuit 62 and an input circuit 64. Once the transmitter 6a sends a synchronizing signal SYC to the transmission line 7, the transmitters 6a-6h start receiving/transmitting operation and assign channels on the basis of the received signal SYS. The receiving circuit 61 inputs the contents of the assigned channel and outputs them to the process equipment 5 through the output circuit 62. The circuit 63 inputs the process information DK to be sent out on the basis of a transmission start signal supplied from the circuit 61.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a signal transmission method, and particularly to a signal transmission method suitable for transmitting and receiving signals between a plurality of information devices.

[Prior art]

When transmitting and receiving necessary information between multiple information devices, they are connected by one common transmission path, and the transmission path is appropriated between specific information devices to transmit information. The signal transmission method using this method is widely known. For example, a configuration shown in FIG. 1 is known as a signal transmission system for transmitting control information (process information) from a control device to an initial number of process equipment such as a plant.

In Fig. 1, the transmission system is transmission unit 1 (la to l
d), and the corresponding receiving units 2 (2a to 2
d) and a transmission line 3 (38 to 3d) formed by connecting these units in series.
~1d each receives process information D from the process source 4.
The information D1 to D4 is transmitted to the corresponding receiving units 2a to 2d via the transmission path 3, and output to the respective process equipment 5. The signal transmitted through the transmission path 3 is formed as a time-series signal having a configuration as schematically shown in FIGS. 2(a) and 2(b).

That is, the transmission signal of one cycle has a channel assigned to the synchronization signal SYC and a channel assigned corresponding to the process information D1 to D4.

The transmitting unit) la forms the synchronization signal SYC and also transmits the process information D! is assigned to a predetermined channel and output to the transmission line 3a. The transmission signal on the transmission path 3a is temporarily stored in the transmission unit 1b. In this transmitting unit 1b, process information D is manually input.
2 and the stored process information are respectively assigned to predetermined channels and output to the transmission path 3b. Similarly, in the transmitting units 3c and 3d, the process information D3 and D4 and the process information received and stored from the transmission lines 3b and 3c are respectively assigned to predetermined channels as shown in FIG. 2(a).

A transmission signal shown in (b) is formed and output to transmission lines 3c and 3d. Note that, as shown in FIG. 2(a), the contents of channels to which no process information is assigned are zero.

In this way, the process information J) I to D4 is transferred to the transmission line 3.
d to the receiving unit 2.

Based on the content of the received synchronization signal SYC, each receiving unit 22 to 2d determines the channel that is the destination for itself from the transmission time, receives the process information in that channel, and processes the process information. It is designed to output to device 5.

According to the conventional signal transmission method described above, is it possible to transmit signals between multiple information devices at substantially the same time via a common transmission path? However, since it is a relay method in which the transmission signal is stored once in each transmitting unit and then retransmitted, if a unit in the middle breaks down or malfunctions, the information may not be transmitted properly. However, it had the disadvantage of low reliability. In addition, although it is possible to accommodate increases and decreases in transmission capacity, in order to make the signal transmission direction unidirectional and bidirectional such as sending and receiving between each information device, the signal transmission system shown in Figure 1 is required. The disadvantage was that two systems had to be provided.

Furthermore, as mentioned above, since the relay method is used, there is a transmission waste time shown in Figure 2 for each unit, and as the number of units increases, the delay in transmitting information increases and the transmission efficiency decreases. was there.

[Purpose of the invention]

An object of the invention is to be able to enable bidirectional transmission,
Another object of the present invention is to provide a signal transmission method with excellent reliability and transmission efficiency.

[Summary of the invention]

The present invention provides a transmission signal as a serial multiplexed signal having a plurality of time-division channels corresponding to each information device and a synchronization signal attached, and each signal transmission device receiving the transmission signal and transmitting the signal to the signal transmission device. Only signals destined for the connected information device are determined and received based on the synchronization signal, and transmission destination information of the transmission signal from the information device connected to the signal transmission device is determined based on the synchronization signal. By assigning and transmitting data to a channel corresponding to a device, it is possible to perform bidirectional transmission and improve reliability and transmission efficiency.

[Embodiments of the invention] Hereinafter, the present invention will be explained based on examples.

FIG. 3 shows an overall configuration diagram of an embodiment of the present invention.

In the drawings, parts denoted by the same reference numerals as those in the conventional example shown in FIG. 1 have the same functions and configurations.

In the figure, the signal transmission device 6 (63 to 6h) is equipped with a transmitting and receiving function, and the general configuration is shown in FIG. 5, and the detailed configuration is shown in FIGS. 7 and 8. These signal transmission devices 6 are all connected to one common transmission line 7. In the embodiment shown in FIG. 3, the signal transmitting devices 6d and 6h are actually required to have transmitting and receiving functions.

That is, as shown in FIG.
Each circuit has a receiving circuit 61 and a transmitting circuit 63 connected to the process equipment 5, process source 4, and process information Dr, D via an output circuit 62 and an input circuit 64.
It is designed to send and receive x (1, -1, 2, 3...).

The structure of the transmission signal is the same as that of the conventional method described above, and as shown in FIG. 4, a synchronization signal sYC is added to the beginning, and it becomes a serial multiplexed signal having a plurality of channels (five in the illustrated example) channels CH1 to CH5. There is. Each of the channels CH1 to CH8 is assigned process information transmitted and received between the information devices, and is assigned a channel number ~D5.

The basic operation of the embodiment shown in FIG. 3 will be explained with reference to the flowchart shown in FIG.

First, a synchronizing signal SYC is sent to the transmission path 7 from one signal transmission device 6 (6a in the illustrated example). When the synchronizing signal sYc is not sent to the transmission line 7 even after a certain period of time has elapsed due to a failure or the like, the synchronizing signal SYC is outputted from the next signal transmitting device 6 in a predetermined order. At step 101 in FIG. 7, the synchronizing signal SYC is sent to the transmission path 7, and at the same time each signal transmission device 6a to
6h starts receiving and transmitting operations, and in step 102, based on the received synchronization signal SYC, the channel CH in the time period for its own transmission and reception is allocated. Next, in step 103, the receiving circuit 61 takes in the contents of the allocated channel CH and outputs it to the process equipment 5 via the output circuit 62. Furthermore, the transmitting circuit 63 takes in the process information DK to be transmitted via the input circuit 64 based on the transmission start signal given from the receiving circuit 61, allocates the information DK to a predetermined channel, and outputs it to the transmission line 7. do. In this manner, when the signal time period for one cycle has elapsed, it is determined in step 104 that one cycle has ended, and in step 105, the synchronization signal detection is cleared and the operation of the next cycle begins.

In this way, each signal transmission device 6 performs transmission and reception operations in synchronization, and bidirectional transmission is performed in the same time zone.

Also, needless to say, since the signal on the transmission path 7 is only one type of transmission signal having the structure shown in FIG. 4, transmission without time delay is possible regardless of the number of transmission devices 6. It will be done.

Note that the synchronization signal SYC may be lost due to a failure of the signal transmission device 6a.
If not, the next signal transmission device 6b confirms that the synchronization signal SYC cannot be received even after a certain period of time, and outputs the synchronization signal SYC instead of the signal transmission device 6a. In case B, the process information DI becomes no signal (an empty channel), and a failure is detected by the signal transmission device 6e on the receiving side.

Next, the detailed configuration of the signal transmission device 6 will be explained based on FIGS. 7 and 8. The receiving circuit 61 is a waveform shaping circuit 60
1, a synchronization detection circuit 602 and a counter circuit 603, and the output circuit 62 includes a reception address setter 606,
The transmission circuit 63 is formed from an address match detection circuit 607, a storage circuit 608, and a buffer circuit 609, the transmission circuit 63 is formed from a clock circuit 610, a synchronization pattern generation circuit 620, and a drive circuit 615, and the input circuit 64 is formed from a level conversion circuit 614 and a multiplexer. 613, an address setter 611, and an address match detection circuit 612.

The waveform shaping circuit 601 shapes the signal waveform input from the transmission line 7 and outputs the received signal 62b to the synchronization detection circuit 602, the storage circuit 608, and the synchronization pattern generation circuit 620. The synchronization detection circuit 602 detects a special pattern of the synchronization signal SYC from the signal 62b and outputs the output signal 6.
2g is set to "1" and the synchronization pattern generation circuit 620
and is output to an AND circuit 604. If the signal 62g is "1", the AND circuit 604 outputs the clock signal 62a of the clock circuit 610 to the counter circuit 603.
It is now possible to input The contents 6-2f of the counter circuit 603 are output to the atsys coincidence detection circuits 607 and 612 and the synchronization pattern generation circuit 620. The address of the channel to which the process information DI to be received is assigned is set in the address setter 606. Address match detection circuit 607 outputs an enable signal (operation permission signal) to storage circuit 608 when the output of address setter 606 and the contents of counter circuit 603 match.

During the period when the enable signal is output, the memory circuit 60
8 receives the received signal 62b based on the clock signal 62a.
is stored and the received signal 62 is stored.
b is output to the process equipment 5 via the buffer circuit 609.

In the signal transmission device 6 that does not require a reception operation, the address set by the address setter 606 may be set to an address equal to or larger than one cycle of the transmission signal (maximum transmission capacity), for example.

On the other hand, at the same time that the content 62f of the counter circuit 603 becomes equal to the address of the maximum transmission capacity and the information transmission of that address is completed, the synchronization turn generation circuit 620 sends out a special pattern of the synchronization signal 8YC in accordance with the clock signal 62a. It is supposed to be done. In a normal state, the transmission device 6a that sends the first process information is required to send out the synchronization signal SYC, and the other devices 6b to 6b are required to send the synchronization signal SYC.
6h is set to be in hibernation state. The address of the channel to which the process information to be transmitted is to be assigned is set in the address setter 611. The Atomes coincidence detection circuit 612 includes an address setter 611 and a counter 6.
Compare the contents 62f of 03, and if they match, the detection circuit 612
is adapted to send an enable signal to the multiplexer circuit 613. During the enable period, the multiplexer circuit 613 outputs the process information Di received from the process source 4 via the level conversion circuit 614 to the OR circuit 605 in synchronization with the clock signal 62a. The OR circuit 605 sequentially sends the synchronizing signal SYC and the output of the multiplexer circuit 613 to the transmission line 7 via the drive circuit 615.

The synchronization pattern generation circuit 620 will be explained based on the detailed configuration diagram shown in FIG. The maximum transmission capacity is set in the setting device 621, and the coincidence detection circuit 62
2 compares the content 62f of the counter circuit 603 with the content of the setter 621, and if they match, it is determined that the final information of one cycle is being transmitted. Then, the next time the matching condition is not established, it is assumed that one cycle of transmission has been completed.
A signal "1" is output to set the flip-flop circuit 623. Furthermore, the counter circuits 626 and 627 are reset to zero by a coincidence detection signal from the coincidence detection circuit 622. The output signal of the flip-flop circuit 623 is converted into a signal by a differentiating circuit 631, and its pulse signal 62c resets the output signal 62g of the synchronization detection circuit 602 to "O" and at the same time resets the contents of the counter circuit 603 to zero. It has become. After this, the contents of counter 1 603 are held at zero until the next synchronizing signal SYC is detected. The coincidence detection circuit 628 uses the signal 62e of the address setter 611 and the counter circuit 62.
7 and if they match, an enable signal is output to the fixed butter/memory circuit 629. During the enable period, the fixed turn memory circuit 629 receives the synchronization signal SY based on the clock signal 62a.
It is designed to output C62d serially.

The operation of the synchronization pattern generation circuit 620 configured as described above will be explained with reference to the time chart shown in FIG. 9(a). In the normal state, the contents of the counter circuit 627 are "zero", so the first process information D! It matches the address of the signal transmission device 6a that sends out the . Therefore,
Fixed pattern memory circuit 629 synchronization signal 5YC62
d is sent. This signal SYC is sent to the synchronization detection circuit 602.
When it is detected, the output signal 62g is set to "1".
Set to . This signal 62g is converted into a pulse by the differentiating circuit 630 and resets the Noritub frog circuit 623. This causes the flip-flop circuit 623 output to be
Since the value becomes "0", the transmission of the synchronized turn is stopped, and then the process information is transmitted via the OR circuit 605.

Next, the operation when the signal transmission device 6a that is supposed to send out the synchronization signal SYC fails will be explained with reference to the time chart shown in FIG. 9(b).

When the synchronization signal SYc is not detected by the synchronization detection circuit 602, that is, when the signal 62b is not set to "1", the AND circuit 625 sends a pulse signal to the counter circuit 626 and the pulse x circuit 626 based on the clock signal 62a. The counter circuit 626 sends a carry signal to the next counter circuit 627 after an arbitrary count number. 9th
In the example shown in FIG. 3(b), a case is shown in which a carry signal is sent out every counter number of "3".

If the content of the counter circuit 627 becomes "1", it matches the address of the signal transmission device 6h that transmits the process information D2, and therefore the synchronization signal sYc will be sent from this signal transmission device 6h. Below, each signal transmission device 6c, 5
d, process information sequentially from 6h, DI + D4 +'
DI is sent to the transmission path 7. This is because the signal transmission device 6a is out of order.

is not transmitted, and a failure condition is detected on the receiving side as described above.

As described above, according to this embodiment, each information device is connected in parallel to one common transmission path via each signal transmission device, so that each signal transmission device performs transmission and reception operations in synchronization. This eliminates wasted time and enables two-way signal transmission during the same time period.The number of signal transmission devices can be easily increased or decreased, which has the effect of easily adapting to system scale. be.

In addition, even if there is a faulty signal transmission device, it is possible to transmit signals between other normal signal transmission devices, and the failure can be detected, improving system reliability. effective.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to make bidirectional transmission possible, and the reliability and transmission efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the conventional system, FIG. Diagram showing the structure, No. 5
3 is a block diagram of the signal transmission device according to the embodiment shown in FIG. 6. FIG. 6 is a flow chart explaining the operation of the signal transmission device shown in FIG. 5. FIG. 7 is a detailed block diagram of the signal transmission device shown in FIG. , FIG. 8 is a detailed configuration diagram of the synchronization pattern generation circuit of the embodiment shown in FIG. 7, and FIG. 9(a), Φ) is a time chart illustrating the operation when the synchronization pattern is generated. 4... Process source, 5... Process equipment, 6 (6a
. 6b, 6C, 6d, 6e, 6f, 6g, 6h)...Signal transmission device, 7...Transmission line. Agent Patent Attorney Tatsuyuki Unuma No. 1 Kuchika 22 □ Prefectural Kaya 3 Diagram 4 Ro-〇j $5 Item No. 7 No. 04-

Claims (1)

[Claims] 1. In a signal transmission system in which signals are sent and received between a plurality of information devices connected to a common transmission path through respective signal transmission devices, each transmission signal transmitted through the transmission path is It has multiple time division channels corresponding to the information device and one
A serial multiplex signal with a synchronization signal output from two signal transmission devices is used, and each signal transmission device receives the transmission signal and synchronizes only the channel of the signal destined for the information device connected to the signal transmission device. In addition to assigning and receiving the signal based on the signal, the transmitting signal from the information device connected to the signal transmission device is assigned to a channel corresponding to the destination information device based on the synchronization signal and transmitted. Characteristic signal transmission method. 2. In the invention described in claim 1, the synchronization signals of the transmission signals are arranged in a predetermined order.
A signal transmission system characterized in that the synchronizing signal is transmitted from one signal transmission device, and when a synchronizing signal is not transmitted to a transmission path for a certain period of time or more, the signal is transmitted from the signal transmission device according to the order.