JPH03186040A - Multiplex communication device with reception signal switching function - Google Patents

Abstract

PURPOSE:To obtain the small-sized, inexpensive multiplex communication device by using all in-use and stand-by multiples transmission lines normally, monitoring the states of the transmission lines, and detecting an abnormal state early if abnormality occurs and switching the transmission lines by respective receiving devices. CONSTITUTION:The in-use and stand-by multiplex transmission lines 1 and 2 are both used normally and the states of those transmission lines 1 and 2 are monitored; is abnormality such as a disconnection occurs, the state is detected early and the receiving device 100 provided for the transmission line switches received signals to carry on the communication. Therefore, neither a monitor node which monitors and controls the communication system nor a monitoring method for a circuit and a procedure for checking the state of a stand-by transmission line which is not used normally is required. Consequently, the whole multiplex communication device is reduced in size, and made simple and inexpensive.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Field of Industrial Application) This invention has a function of constantly using all multiplexed transmission lines and detecting abnormalities in the transmission lines such as disconnections and switching signals. The present invention relates to a multiplex communication device having.

(Prior art) As a conventional multiplex communication device having a signal switching function,
For example, there are the ones shown in Figures 6 and 7 (
(See Japanese Patent Application Laid-Open No. 61-274449).

In a multiplex communication system, in order to improve safety and reliability, the transmission lines are duplicated so that even if an abnormality such as a disconnection occurs in the transmission system, communication can be continued by switching to a backup transmission line. is being used.

FIG. 6 shows a coupling device 40, 41, 42 connected to two sets of transmission lines 4.
3 and 44 in a ring shape, and the current transmission line 4
3 is a communication system configured such that each coupling device 40, 41.42 is coupled to one or more nodes 45, 46, 47, 48, 49, 50 in a ring shape.

FIG. 7 also shows a switch 51 for switching the transmission line.
and 52, a changeover switch 53 for branching the signal on the working transmission line 43 to the protection transmission line 44 via the branch line 55, and a monitoring unit 54 for monitoring the signal on the protection transmission line 44. It is.

In this conventional example, the monitoring node 47 constantly monitors the signal on the working transmission line 43, and when it detects that an abnormality has occurred on the working transmission line 43, each coupling device 40, 41
．． 42 to switch the transmission path.

In accordance with this instruction, the changeover switch 51 or 52 is operated to connect the working transmission line 43 to the protection transmission line 44 in a looped manner, thereby forming a ring-shaped transmission line excluding the part where the abnormality has occurred.

Therefore, the backup transmission line 44 needs to be kept in a normal state at all times in case an abnormality occurs in the working transmission line 43.

Therefore, in one coupling device in the system, the changeover switch 53 is operated to branch the signal on the working transmission line 43 to the protection transmission line 44, and the branched signal is transferred to the protection transmission line 44.
The monitoring unit 54 monitors the status transmitted by the data.

(Problem to be Solved by the Invention) However, in such a conventional multiplex communication device having a signal switching function, the actual communication signal always flows through the active transmission line among the duplex transmission lines. A monitoring node is required to monitor and control a communication system. One of the backup transmission lines is always kept as a backup.
Since it is not in use, a monitoring method is required, such as circuitry and procedures to check this transmission line. For this reason, there has been a problem that communication systems have become larger and more complex, and therefore more expensive.

This invention was made by focusing on such conventional problems, and uses all of the multiplexed transmission lines (current and backup) at all times, monitors the status of these transmission lines, and detects abnormalities such as disconnections. The purpose of this invention is to solve the above problem by providing a compact and low-cost multiplex communication device in which the condition is quickly detected when it occurs, and each receiving device switches the transmission path.

[Horizontal of invention 6. (Means for Solving the Problems) In order to achieve the object, the present invention provides delay means with different delay times in each transmission system of a simultaneous transmission multiplex transmission line, and multiplexes the signals in the receiving sections of a plurality of control devices. Each decoding circuit is equipped with one system of decoding circuits, which monitors the pulse signal generated when the circuit receives data, and instructs the one that receives the pulse signal earlier to change the switch. The multiplex communication device is provided with a switching signal generating circuit for switching, and a switching circuit for switching the decoded data output from the decoding circuit according to instructions from the circuit.

(Function) The signals sent through the multiplex transmission paths are sent to the decoding circuits with time differences due to the delay means for each transmission system.
It reaches the switching signal generation circuit. This circuit instructs the subsequent switching circuit to switch only to the transmission line to which the pulse was input early, so that the signal is reliably sent through one of the multiple transmission lines. At this time, the receiving section monitors and determines whether there is any abnormality in other transmission paths. Therefore, if the current transmission path is abnormal, signal transmission can be performed immediately in place of the current transmission path without inspecting and detecting the presence or absence of abnormality in the other transmission path (next priority transmission path).

(Example) Hereinafter, an example of the present invention will be described based on the drawings shown in FIGS. 1 to 4.

FIG. 1 is a block diagram showing an embodiment of a receiving section of a control device in a multiplex communication device of the present invention.

In this figure, in this embodiment, 100 is a receiving section of the control device, and the transmission paths are transmission path (A) 1 and transmission path (B) 2.
These transmission lines (A) 1ε
(B) 2 is configured so that it can simultaneously transmit to the receiving section 100. The circuit configuration of this embodiment in the receiving section 100 includes a PWM decoder (decoding circuit) 5 that decodes data A from the transmission path (A) 1 and a delay for data B from the transmission path (B) 2. A delay circuit 3 that decodes the delayed data B, a PWM decoder (decoding circuit) 9 that decodes the delayed data B, outputs 8 from the PWM decoders 5 and 9, and data A from the transmission path (A) 1
a switching signal generating circuit 13 which determines whether to receive data B or data B from the transmission path (B) 2; a switching circuit 16 which is switched by signals 14 and 15 from the switching signal generating circuit 13; It is composed of a serial-parallel conversion circuit 19 that converts data into parallel data. However, the delay circuit 3 may not be provided in the receiving section 100 but may be provided on the transmitting section side.

Although the transmission path A is not substantially provided with a delay circuit, it is equivalent to providing a delay circuit with zero delay time.

Furthermore, when providing delay circuits on transmission lines A and B, it is necessary to provide delay circuits having different delay times.

All these transmissions are carried out using communication cables 4,6°7.10
, 11. ．． 17.18.

FIG. 2 is a diagram showing an embodiment of the switching signal generating circuit 13 in the multiplex communication device of the present invention.

Its configuration includes two T-type flip-flops 20.22 and two OR circuits 24.26.

FIG. 3 is a diagram showing an embodiment of the switching circuit 16 in the multiplex communication device of the present invention.

Its configuration is a D-type flip-prop 29. ．． 31°33
．． 35 and two OR circuits 37 and 38.

All these transmissions are carried out through communication cables 25, 27° 28 (
Above, Figure 2) and 30, 32.34° 36.39
(The above is shown in Fig. 3).

FIG. 4 is a waveform diagram showing the operation in the multiplex communication device. The operation of this embodiment will be explained based on this figure.

Data input is sent from the transmission path (A) 1, and data B is sent from the transmission path (B) 2 at the same time.

At this time, if there is no abnormality in the transmission paths (A) 1 and (B) 2, the PWM decoders 5 and 9 can receive data A and data B simultaneously.

Due to the signal selection method described below, in order to avoid manually inputting one-shot signals to the switching signal 13 at the same time,
A delay circuit 3 is provided on the transmission line (B) side.

The PWM decoder 5 outputs a one-shot signal 8 when detecting a rise from a continuous state of non-communication rLJ.

It also outputs data 6 obtained by decoding the human data A by the PWM decoder 5 and a clock 7 synchronized with this data 6.

Similarly, the PWM decoder 9 of the transmission path (B) 2 also outputs data 10.
However, the manual data 4 to the PWM decoder 9 is delayed by T seconds by the delay circuit 3. Therefore, the output signals 10, 11, 12 of the PWM decoder 9 are P
The output signals 6, 7.8 of the WM decoder 5 are all delayed by T seconds. Note that the output signals 1o and 11 are omitted in FIG. 4 because they are too cluttered.

The one-shot signals 8 and 12 are input to T-type flip-flops (hereinafter referred to as T-F/F) 20 and 22, respectively, of the switching signal generation circuit 13.

When the one-shot signal 8 is input to the TF/F 20, the output Q21 rises to rHJ, and the TF/F 22 is reset.

Here, since the T-F/F22 is in a reset state, even if the one-shot signal 12 is input, the output is 02.
The state of No. 3 remains rLJ and does not change. Therefore, the switching signal 14 becomes "L" and the switching signal 15 becomes rHJ.

The switching signal 14.15 is a D-type flip-flop (hereinafter referred to as D-F/F) '29, 31 of the switching circuit 16.
．． Since it is connected to the reset terminal of 33.35, D
-F/F33.35 is reset and decoded data 1o and clock 11 synchronized with this are not output,
Decoded data 6 and clock 7 from the transmission path A side are transmitted to the serial-parallel conversion circuit via switching circuit 16 by switching signals 17 and 18.

Therefore, even if the transmission path is duplicated, the receiving unit 100 receives a signal from the transmission path A side that is normal and operates the control device.

At this time, it goes without saying that the effectiveness of the transmission path B side is also monitored by the receiving section 100.

Here, if any abnormality occurs on the transmission line A side, the transmission line B side is constantly monitored for abnormality, and if there is no abnormality, the switching signal generation circuit 11 and the switching circuit 16 act to The signal transmission path is switched to activate the control device.

That is, the one-shot signal 8 is not generated, the signal 12 is sent to the switching generation circuit 13, the T-F/F 20 is reset, the switching signal 14 is set to rHJ, and the signal 15 is set to r.
As LJ, I)-F/F29 of switching circuit 19
and 31 are reset, decoder data 10 and a clock 11 synchronized therewith are outputted, and the signal is transmitted through a transmission line B via a serial-parallel conversion circuit 19.

Therefore, according to the above embodiment, during normal operation, one of the dual transmission lines plays the role of transmission, and at the same time monitors the other transmission line for abnormality. , the switching can be performed immediately without inspecting and detecting the normality of other transmission lines, and therefore the switching can be performed smoothly and economically.

Next, another embodiment of the multiplex communication apparatus of the present invention will be described with reference to the block diagram of FIG.

This embodiment has a configuration in which an inverter circuit 57 is connected before the delay circuit 13 on the transmission path B side in the receiving section 100 of the control device in the embodiment shown in FIG.
Balanced lines are used in the transmission lines (A) and (B) to invert the phase of one signal for transmission.

In the case of the embodiment shown in FIG. 1, there is no problem whether the delay circuit 3 provided to determine the standby system is in the receiving section or the transmitting section of the control device.

However, in the case of this embodiment, due to the characteristics of the balanced line, signals transmitted with completely opposite phases can have the effect of reducing the noise by canceling out the generated noise.
If the phase shifts, the noise reduction effect decreases, so the delay circuit 3 must be installed in the receiving section of the control device.

The operation is similar to that of the first embodiment except for the noise reduction effect.

In the embodiment shown in FIG. 5, if the transmission lines A and B are Lecher wires, the inverter circuit 57 becomes unnecessary.

As explained above, in the multiplex communication device having the received signal switching device of the present invention, the transfer path (A)
The status of the multiplexed transmission paths (1 and 2) is monitored, and when an abnormality such as a disconnection occurs, the condition is quickly detected, and the reception device installed on each transmission path switches the received signal. By communicating, the safety and reliability of the communication system can be increased.

Although one embodiment of the present invention has been described above in detail with reference to the drawings, the multiplex communication device having a specific reception signal switching function is not limited to this embodiment, and the transmission path may be, for example, triplexed. Even if the number of multiplexed transmission paths is more than 1,000,000, it is sufficient to provide a delay means for each of them.Therefore, even if there are any changes that do not depart from the gist of the present invention, they still fall within the technical scope of the present invention.

[Effects of the Invention] As is clear from the invention described above, according to the present invention, all of the multiplexed transmission lines, both active and backup, are constantly used, the status of these transmission lines is monitored, and disconnections, etc. When an abnormality occurs, the condition is detected early and the reception device installed on the transmission path switches the received signal and performs communication, thereby monitoring and controlling the communication system.A monitoring node that is not normally used This eliminates the need for monitoring methods such as circuits and procedures to check the status of the Senryo transmission line.
The overall multiplex communication device can be made smaller and simpler, resulting in lower cost, and it is possible to improve the safety and reliability of the communication system.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a control device receiving section in a multiplex communication device of the present invention, and FIG. 2 is a circuit diagram showing an embodiment of a switching signal generation circuit in the multiplex communication device of the present invention. 3 is a diagram showing an embodiment of the switching circuit in the multiplex communication device of the present invention, FIG. 4 is a waveform diagram showing the operation in the multiplex communication device of the present invention, and FIG. 5 is a diagram showing an embodiment of the switching circuit in the multiplex communication device of the present invention. A block diagram showing another embodiment,
FIG. 6 is a block diagram illustrating the configuration of a conventional communication system, in which (a) shows a normal case, (b) shows an abnormal case, and FIG. 7 shows a conventional multiplex communication device. It is a block diagram of a payment device in.

Claims (1)

[Claims] (1) In a multiplex communication device that transmits data signals through transmission paths in which a plurality of control devices are multiplexed, each transmission system of the simultaneous transmission multiplex transmission path is provided with delay means with different delay times,
One decoding circuit is provided for each of the multiplexed transmission lines in the receiving section of the control device, and the decoding circuit monitors the pulse signal generated when the data is received, and the pulse signal is A switching signal generating circuit is provided which instructs the switch to be switched to the one that is input earlier, and a switching circuit is provided which switches the decoding signal output from the decoding circuit according to the instruction from the switching signal generating circuit. A multiplex communication device having a characteristic reception signal switching function.