JP2606442Y2 - Information bit control device in loop transmission - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information bit control device for loop transmission.

[0002]

2. Description of the Related Art FIG. 3 is a schematic configuration diagram of a loop transmission device.
In FIG. 3, A to D are stations (stations), and these stations A to D are connected in a loop by transmission lines CAB ₁ and CAB ₂ . In the loop transmission apparatus configured as described above, information bits are added to the loop transmission path (the reason for adding the information bits is that information transmission to each station is performed at high speed when a disconnection occurs in the transmission path or the like. This is a method of controlling the state transition of each station A to D (switching the transmission path due to disconnection or the like) by turning in a loop.

In the stations A to D described above, the detection of disconnection of a transmission line or the like is performed by an information bit monitoring circuit 41 and an abnormality detection circuit 42 provided in each of the stations A to D shown in FIG. That is, the information bit monitoring circuit 41 monitors the information bits, and provides the information bits to the abnormality detection circuit 42. When the information bits are no longer supplied, for example, a transmission stop command is supplied from the abnormality detection circuit 42 to the transmitter 43. Is done. Thereafter, a loopback state is established by the transmission line switching circuit shown in FIG. In FIG.
51 is an LSI, 52 is a CPU, 53a and 53b are flag detection units, and 54 is a flag transmission unit.

[0004]

[Problems to be Solved by the Invention] In a state where an information bit is rotating in the loop transmission, the information bit changes from "1" to "0" or from "0" to "1" (normal transition or abnormal state of the loop). At the time of switching, the old information bit may remain in the loop due to an actual circuit delay or the like. In such a case, information bits "1" and "0" are mixed in the same loop. Normally, as shown in FIGS. 6A and 6B, the same loop is in one of the states when the information bit is “1” or “0”. However, conventionally, there is a problem that old information bits remain in the loop as described above. Each of the stations A to D monitors the information bit by the information bit monitoring circuit 41 shown in FIG. 4, and switches the transmission path based on the monitoring result (the switching circuit is shown in FIG. 5). Therefore, it has been difficult to complete a stable loop having information bits as shown in FIGS. 6A and 6B.

The present invention has been made in view of the above circumstances, and has been made in view of the above circumstances, and is intended to prevent information bits from mixing "1" and "0" in the same loop and to construct a stable loop state. It is an object of the present invention to provide an information bit control device in the above.

[0006]

Means for Solving the Problems To this invention is to achieve the above object, Rutotomo a plurality of stations in the transmission line connecting the transmission line that is duplicated in a loop
To the loop transmission path by adding information bits to the transmission path.
And monitor the information bits with the information bit monitoring circuit
The information bit is supplied to the abnormality detection circuit,
If a station has an error, its information bit is detected as an error.
Is not supplied to the output circuit, and the abnormality detection circuit
In the loop transmission control device in which an abnormal part is separated from the transmission line and an information bit is looped back, each station is provided with an information bit prohibition circuit and a toggle pulse generation circuit, and the abnormality detection circuit detects an abnormality. when, with providing a signal for stopping a predetermined time the transmission of information bits to the information bits inhibiting circuit sends a Toguruparusu the transmission line provides a signal for operating the Toguruparusu generating circuit, the Toguruparusu
While monitoring by the information bit monitoring circuit, the loop
Toggle pulse by setting the time longer than necessary for one round
The information bits of each station are
It is characterized in that it can be switched between a normal state and an abnormal state .

[0007]

When the abnormality detection circuit detects an abnormality, it supplies the detected signal to the information bit prohibition circuit to stop the operation of the circuit for a certain period of time. The toggle pulse is transmitted from the toggle pulse generation circuit during this fixed time. This toggle pulse is set to a time equal to or longer than the time required for making one round of the loop.
Therefore, the information bit of each station is switched to the “1” state or the “0” state during one cycle of the toggle pulse.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In Figure 1, the transmission path CAB ₂ information bits inhibit circuit 11 of the station A to the transmitter 43 is provided
Interpolate. The information bit prohibition circuit 11 is supplied with an inhibit signal from the abnormality detection circuit 42 and transmission of information bits is stopped. 12 is a toggle pulse generation circuit,
The toggle pulse generation circuit 12 is operated by a signal when the abnormality detection circuit 42 detects an abnormality, and a toggle pulse is transmitted from the transmitter 43 to the transmission line. As a result, the state of the information bit changes from “0” → “1” → “0” → “1”. As shown in FIG. 2, the information bit monitoring circuit 41 determines this change as the time (TA seconds) of the information bit "1" and "0".
(TB seconds). This information bit is monitored by the own station, and the state is switched when the specified TA seconds and TB seconds are detected. That is, a loopback connection state is established. At this time, TB seconds + α
The station that detects (α is a time in consideration of the delay of each circuit) switches from an abnormal state to a normal state.

When the station is switched to the normal state, an information bit inhibiting circuit 1 using an inhibit signal is used.
After the transmission stop of 1 has elapsed for a time equal to or more than TB seconds + α,
Release the inhibit signal. TA seconds shown in FIG. 2,
The setting of TB seconds is set to be equal to or longer than the time required for making one round of the loop. In FIG. 1, 13 is a PLL circuit, and 14 is a FIFO circuit.

[0010]

[Effect of the invention] As described above, according to the invention,
By transmitting a toggle pulse at the time of an abnormality, the state of “0” and the state of “1” are not mixed in the loop transmission path, and a stable loop state can be constructed. Further, by providing the information bit prohibition circuit, the transmission of the information bits can be stopped at the time of abnormality, and the information bits in the loop transmission path can be fixed.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing an embodiment of the present invention.

FIG. 2 is a timing chart.

FIG. 3 is a schematic configuration diagram of a loop transmission device.

FIG. 4 is a schematic configuration diagram of a conventional station.

FIG. 5 is a diagram of a conventional transmission line switching circuit.

FIGS. 6A and 6B are explanatory diagrams showing states of information bits in a loop transmission installation.

[Explanation of symbols]

 11 Information Bit Prohibition Circuit 12 Toggle Pulse Generator 41 Information Bit Monitoring Circuit 42 Abnormality Detection Circuit 43 Transmitter

Claims (1)

(57) [Scope of request for utility model registration] 1. A two transmission paths which is duplicated by connecting in a loop a plurality of stations in its transmission path Rutotomoni,
By adding information bits in the transmission path,
And the information bit is monitored by an information bit monitoring circuit.
The information bits are supplied to the abnormality detection circuit, and the
If there is an error in the operation, the information bit is
Is no longer supplied to the road, and the abnormality detection circuit detects the abnormality.
In the loop transmission control device in which the abnormal part is separated from the transmission line and the information bit is looped back, each station is provided with an information bit prohibition circuit and a toggle pulse generation circuit, and when the abnormality detection circuit detects an abnormality. to, along with providing a signal for stopping a predetermined time the transmission of information bits to the information bits inhibition circuit, the Toguruparusu giving signals for operating the Toguruparusu generating circuit is transmitted to the transmission path, the information bits of this Toguruparusu
In order to monitor with a monitoring circuit and go around a loop
Set the time longer than necessary and the toggle pulse goes around the loop once
Information bit of each station is normal or abnormal
An information bit control device in loop transmission, wherein the information bit control device can be switched to a state .