JPH02193433A - Warning detection system for loop type data transmitter - Google Patents

Abstract

PURPOSE:To accurately detect the abnormality of each slave station by sending a zero bit as a bit for warning detection when a master station sends data, and adding a specific number to the bit and sending the sum when each slave station receives them normally. CONSTITUTION:When the master station MS sends data to the respective slave stations SS1-SSN, a U/D bit indicating whether the data are sent upward or downward is used as the bit for warning detection and 0 is sent as the bit. The slave station SS1 which receives the bit normally adds 1 as the specific number to the bit and sends the sum to the slave station SS2, which receives it similarly, further adds 1 to the bit, and sends the result as 2 to the next slave station SS3. Thus, the following slave stations SS3-SSN adds 1 to the bit and sends the result as long as the data can be received normally. The master station MS judges that some slave station enters an abnormal reception state unless the value of the U/D bits is N, thereby detecting communication abnormality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a system for detecting a communication abnormality alarm in a loop data transmission device.

[Conventional technology]

A loop-type data transmission device connects a master station and multiple slave stations in a loop through a transmission path, and transmits data from the master station to each slave station in a fixed direction, as well as between each slave station and each slave station. Data is also transmitted and received between the slave station and the master station in the same way, and when the master station sends data to each slave station, it sets the alarm detection bit to "0" and sends it. The slave station that receives this normally sets the alarm detection bit to "1" and transmits it to the next slave station. When the bit is "1", it is determined that the communication status is normal, and when the bit is "0", it is determined that the communication status is abnormal, and an alarm is detected based on this.

[Problem to be solved by the invention]

However, in the past, even if one of the slave stations did not perform normal reception, if another slave station received normal reception, the alarm detection bit would be displayed as "1", and the master station would be able to communicate correctly. The disadvantage is that it is not possible to perform alarm detection of abnormalities.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention is configured by the following means.

In other words, in the above-mentioned loop data transmission device, when data is transmitted from the master station, the alarm detection bit is set to zero, and when this is successfully received, the round can child station sets the alarm detection bit to a specific number. is added to each unit and transmitted, and upon receiving this, the nine master stations detect a communication abnormality alarm when the value indicated by the same bit is equal to the product of the specific number and the total number of slave stations. .

[Effect]

Therefore, if the reception status of all slave stations is normal, the specific number is n1, the total number of slave stations is N, and the alarm detection bits received by the master station are n-N; When the reception state becomes abnormal in a slave station, the value indicated by the same bit is always neN, and it is possible to accurately detect a communication abnormality alarm.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 4 is a block diagram of the entire configuration, in which a master station MS and a plurality of slave stations SSt to 88N are connected in a loop through a transmission line t11t2, the transmission line t1 is counterclockwise, and the transmission line t2 is clockwise. In this case, the transmission line is currently in use, and the transmission line L! is in reserve.

Furthermore, when the master station MS transmits data to each slave station 5S1=SS, the image transmission paths t1, t! However, each slave station SS, ~SSM receives only the data on the transmission line tl and sends it to the next slave station, whereas the data on the transmission line L2 is transmitted to the next slave station under normal conditions. Only relay transmission is performed.

In this case, when the master station MS transmits data to each of the slave stations SS1 to SSN, it uses the U/D bits, which represent the upper and lower sides of the data, as alarm detection bits, and sends the data with OK. and the slave station S that successfully received this
81, adds 1 to the same bit as a specific number and transmits it to the slave station S82, and the slave station SSx, which similarly receives this, further adds 1 to the same bit, sets this as 2, and transmits it to the slave station S82. As long as the data is transmitted to the station 88m and can be received normally, the subsequent slave stations SSs-8SN Ic also add 1 to the same bit and transmit it.

Therefore, in the transmission from the slave station SS, the same bit is N
In the master station MS that receives this, if the value indicated by the U/D bit is N, the total number of slave stations is N.
and the specific number 1, it is determined that the reception status of all slave stations SSt to SSs is normal, and when the value indicated by the same bit is other than N, it is determined that the reception status of any slave station has become abnormal. However, this makes it difficult to detect a compensation abnormality alarm.

Figure 2 shows the master station MS and each slave station SS! ~ It is a block diagram showing the configuration of SSN, and it is a bypass control unit (hereinafter referred to as RP
C) 1 accommodates the transmission paths '1, Zl, and during normal operation, the reception side transmission path t1. Synchronization control unit (hereinafter referred to as 5YC)
) 2, while transmitting the output of the transmitting/receiving unit (lower, 8RD) 3 to the transmitting side transmission line tl, and transmitting the signal from the receiving side transmission line 12N directly to the transmitting side transmission line t2. However, when searching for faulty parts and taking countermeasures when a fault occurs, transmission lines t1m and t2 are
．． or between the transmission lines t2m and tl.

In addition, the received data via 8YC2 is checked in the 5RD3 for the 7-frame check sequence part in the received data, and if this is normal, the received data is transferred to the terminal device (hereinafter referred to as TE) via the interface (hereinafter referred to as r/F) 4. ), on the other hand, the transmission data from the TE is changed into a frame in 5RD3, further has U/D pits added in the U/Dk' cut insertion section (hereinafter referred to as Br5), and is sent to the BPcl via the transmission path t1. sent to.

However, 5YC2 and BIS5 are installed only in the master station MS! While 0.5YC2 performs general monitoring and correction of transmission delay time, each slave station 8s1 to ss,
Addition circuit (hereinafter referred to as ADD) 6 strange! Added, 5R
D3 checks the frame check sequence part of the received data, and if it is normal, the U/D bit added to the data sent from TK changes to the value indicated at the time of reception.
D6 adds 1 and transmits it via BPCI.

In addition, in the master station MS, in addition to 5YC2 and BIS5, an alarm detection unit (hereinafter referred to as ALD) 7 is provided.
Check the U/D bit in the data received via PCI and determine whether the value indicated by this is equal to N1, that is, the product of the specific number and the total number of slave stations. Detects an abnormality alarm, sends a signal indicating this from ALD7 to 5YC2, and further sends a control signal CB from 8YC2 to BPCl.
It is intended to issue commands to St to SSN.

〔Effect of the invention〕

As is clear from the above explanation, υAccording to the present invention, when transmitting data from the master station, the alarm detection bit is set to zero, and each slave station transmits the same bit when it receives the data normally. Add a specific number to each item and send it to
When the master station receives this and the value indicated by the same bit is not equal to the product of the specific number and the total number of slave stations, it detects a communication abnormality alarm.This allows accurate detection of abnormalities in each slave station. If this is possible, remarkable effects can be obtained in loop type data transmission devices for various uses.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention; FIG. 1 is a block diagram of the entire configuration, and FIG. 2 is a block diagram showing the configurations of a master station and each slave station. 2...Synchronization control unit, 3...Transmission/reception unit, 5...
・[J/D bit insertion section, 6...addition circuit, γψ・
...Alarm detection unit, MS...Further station, SJ ~ SSN
""-Slave station, tH, 1, 2 "" Transmission line.

Claims (1)

[Claims] A master station and multiple slave stations are connected in a loop through a transmission line,
In a loop data transmission device that transmits data from the master station to each slave station in a fixed direction, when transmitting data from the master station, the alarm detection bit is set to zero and the transmission is performed normally. Each of the received slave stations adds a specific number to each of the alarm detection bits and transmits the same.
The loop data transmission device is characterized in that the master station receiving the transmission detects a communication abnormality alarm when the value indicated by the alarm detection bit is not equal to the product of the specific number and the total number of slave stations. alarm detection method.