JPH09312659A - Transmitter-receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the transmitter-receiver by which a function of a system is maintained even on the occurrence of disconnection of a line. SOLUTION: Two lines as a main line 1A and a sub line 1B are communication lines to interconnect a master station A and a plurality of slave stations B. The master station A and a plurality of the slave stations B send the same data to both of the two lines in the case of transmission. The reception is conducted basically by using the main line 1A, and the master station A and a plurality of the slave stations B detecting a line fault select the sub line 1B automatically as the reception line by the operation of a reception changeover circuit 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission / reception apparatus for performing communication between a master station and a plurality of slave stations via a line commonly connected between these stations in a link format.

[0002]

2. Description of the Related Art Conventionally, in an automatic warehouse control system, for example, a parent controller (parent station) for managing the entire warehouse and each child controller (child station) for managing a cargo handling crane for each shelf of the warehouse There is known a transmission / reception apparatus in which the RS is connected via an RS-485 communication line. In RS-485, normally, a master station and each slave station are commonly connected by one line in a link format.

[0003]

In the conventional transmitter / receiver of this type, since the line connecting the master station and the slave station is one line, if a line break occurs in the middle of the line, the disconnection position There is a problem in that communication between the slave station and the master station arranged thereafter becomes impossible, and the function as the system cannot be achieved. Particularly in the case of an automatic warehouse, since the slave station moves, the communication line is easily broken due to the stress caused by the movement.
Further, the conventional transmitter / receiver has a problem that it takes a considerable amount of time to identify the disconnection position of the line.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems, and to provide a transmitter / receiver capable of maintaining the function of the system even if the line is disconnected and automatically identifying the disconnection position.

[0005]

SUMMARY OF THE INVENTION The present invention is a transmission / reception apparatus in which communication between a master station and a plurality of slave stations is performed via a line commonly connected to these stations, and the main line is used for the communication. Two lines, a line and a sub-line, are sent, and the same data is sent to both of the two lines by the master station and the plurality of slave stations, and the transmission data from the master station is sent to each of the slave stations. Line abnormality detection means for detecting an abnormality of the main line based on whether or not the received line matches a predetermined abnormal state, and a reception line that switches the reception line from the main line to the sub line in response to the detection output of the line abnormality detection means. A switching means is provided.

Each of the slave stations is further provided with a recording means for recording the number of times of reception by the line from the master station, and the master station records the number of times of transmission from itself and the recording means of the slave station. A determination means for determining the position of the line abnormality based on the comparison with the number of receptions by line may be provided.

The colors of the cables of the main line and the sub line may be different from each other.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. This transmission / reception device performs communication between, for example, a controller A for overall management of an automated warehouse and controllers B mounted on a plurality of cranes that move articles in and out of each shelf of the automated warehouse. . As shown in FIG. 1, between the controller A for overall management (hereinafter referred to as a master station) which is a master station and the controller B for each crane (hereinafter referred to as a slave station) which is a slave station, Main line 1 using RS-485 respectively
Two lines, A and sub line 1B, are commonly connected in a link format. Each of the lines 1A and 1B is shown as a single line for convenience of illustration, but each has a transmission line and a reception line. Also, the main line 1
The cable of A is, for example, red, and the cable of the sub line 1B is, for example, black so that both lines can be identified by the color of the cable. As a result, it is possible to eliminate connection mistakes in the connection work of the line and surely and easily perform the work.

As shown in FIG. 2, each slave station B includes a first transmission driver 2A and a first reception driver 3A connected to the main line 1A, and a second transmission driver connected to the sub-line 1B. 2B and the second receiving driver 3B. Both receiving drivers 3A, 3B
Is a circuit unit for inputting and amplifying a signal transmitted from the master station A, and these reception signals are selectively switched by the reception switching circuit 4 and the serial controller 5 at the latter stage.
Sent to. That is, in the initial state, the reception switching circuit 4 selects the output of the first reception driver 3A which is the reception signal from the main line 1A, and when the reception switching signal a is received from the CPU 6 described later, the reception switching circuit 4 receives from the sub line 1B. The output of the second receiving driver 3B, which is a signal, is switched and selected.

Both of the transmission drivers 2A and 2B are circuit portions for receiving a signal to be transmitted from the slave station B to the master station A from the serial controller 5, amplifying the signal, and transmitting the amplified signal to each of the lines 1A and 1B. The serial controller 5 is a circuit unit that performs input / output processing of a transmission signal and a reception signal.
It is controlled by the CPU 6 which controls the whole. Also,
The CPU 6 detects the abnormality of the main line 1A based on whether or not the transmission data from the master station matches a predetermined abnormal state. That is, the CPU 6 monitors a specific error response from the serial controller 5, outputs a count signal to the counter 7 when this occurs, and when the count value reaches a predetermined value (for example, 3), the main circuit 1A receives the count signal. For example, it is determined that there is an abnormality such as disconnection, and the reception switching signal a is output. In this case, the error response is, for example, a time-out (a non-detection state is a predetermined state) in a frame reception monitoring process (a monitoring process of a predetermined frame identification code that should appear on the line at a relatively short time interval). (Exceeding the time). For example, the error determination is made by the error response of three consecutive times. In this way, the serial controller 5 and the CPU 6 constitute line abnormality detecting means for detecting an abnormality in the main line 1A. Logging circuit 8 connected to the serial controller 5
Is a circuit for recording the number of reception signals from the main line 1A and the number of reception signals from the sub line 1B which are input to the serial controller 5.

The master station A has substantially the same function as the slave station B. That is, similar to the slave station B in FIG. 2, the first transmission driver 2A and the first reception driver 3A connected to the main line 1A, and the second transmission driver 2B and the second reception driver 3B connected to the sub line 1B. Have and. Further, it has a reception switching circuit 4, which switches and selects one of the reception signals of the both reception drivers 3A and 3B, a serial controller 5, a CPU 6, a counter 7, and a logging circuit 8. In this case, the logging circuit 8 records the number of times of reception from each slave station B for each line. The counter 7 counts, for example, the number of NG (unconnected process) occurrences in the participation confirmation permission sequence for each child station B. For example, the CPU 6 determines that there is an abnormality in the main line 1A by three consecutive NGs, outputs the reception switching signal a, and switches the line from the main line 1A to the sub line 1B. Also, CP
In U6, the number of transmissions from the master station A to the slave station B, the number of receptions by line recorded in the logging circuit 8 on the slave station B side, the number of transmissions from the slave station B to the master station A, and the master station A side Based on the number of line-by-line receptions from each slave station B recorded in the logging circuit 8, the presence or absence of a line abnormality in each of the lines 1A and 1B is checked and the line abnormal position is determined. That is, the CPU 6 of the master station A
Also constitutes a judging means for checking the presence / absence of a line abnormality in the lines 1A and 1B and determining the line abnormal position.

Next, the operation of the transmitter / receiver will be described.

A transmission signal from the master station A to each slave station B and a transmission signal from each slave station B to the master station A are sent to both the main circuit 1A and the sub circuit 1B. On the other hand, in the initial state, the slave station B accepts the transmission signal from the master station A transmitted to the main line 1A as a reception signal, and the master station A also transmits the transmission signal from each slave station B to the main line 1A. The reception switching circuit 4 of each station is switched and selected so that the signal is received as a reception signal.

When the main line 1A is disconnected at a position near the master station A in an arbitrary slave station B (more accurately,
When the reception line seen from the slave station B in the main line 1A is broken), the reception signal is not input from the first reception driver 3A to the serial controller 5. As a result, the serial controller 5 outputs an error response, and in response to this, the CPU 6 sends a count signal to the counter 7. When the count value of the counter 7 reaches 3, that is, when the time-over continues three times in the frame reception monitoring process, the CPU 6 transmits the reception switching signal a to the reception switching circuit 4, and the reception switching signal a is received in response to this. The switching circuit 4 switches to a state of selecting the output of the second reception driver 3B which is the reception signal from the sub line 1B. As a result, unless the sub line 1B is disconnected, the main line 1
Despite the disconnection of A, the function of the transmitting / receiving device can be maintained thereafter. If reception is normally restored before the count value of the counter 7 reaches 3, the counter 7 is reset and the count value returns to 0.

The above operation is almost the same on the master station A side. That is, when the main line 1A is disconnected (more accurately, when the reception line seen from the master station A in the main line 1A is disconnected), when the count value of the counter 7 reaches 3, the reception switching circuit 4 is switched, and the output of the second reception driver 3B, that is, the transmission signal from each slave station B sent to the sub line 1B is input to the serial controller 5 as a reception signal. As a result, the function of the transmission / reception device can be maintained even after the main line 1A is disconnected.

Further, the presence / absence of a line abnormality and the identification of the abnormal position are performed in the master station A as follows.

(A) Confirmation of Abnormality of Transmission Line and Identification of Abnormal Position Seen from Master Station A (A-1) First, the logging circuit 8 in each slave station B from the master station A to each slave station B Instruct to transmit the data of the number of times of reception for each line recorded by.

(A-2) In response to this, the line count reception count data transmitted from each slave station B to the master station A is sent to the master station A.
CPU 6 counts up. Based on the counting result, the number of transmissions from the parent station A and the number of receptions by line of each child station B are compared,
Check whether there is a line error and identify the position where there is a possibility of an error. Referring to FIG. 1, main line 1 of each slave station B
If the number of receptions by A is all equal to the number of transmissions, then C
The PU 6 determines that the main line 1A is normal. Now, if each slave station B is numbered B1, B2 ... Bn from the side closer to the master station A, for example, the main line 1 of the slave stations B1, B2
When the number of receptions by A is equal to the number of transmissions and the number of receptions by the main line 1A in the child station B after the child station B3 is smaller than the number of transmissions, the CPU 6 determines that
At a position between 3 and 3, it is determined that at least the transmission line in the main line 1A has a disconnection. In the slave stations B from the slave station B3 to the slave station B5, the sum of the number of times of reception by the main line 1A and the number of times of reception by the sub line 1B is equal to the number of transmissions, and the slave stations B6 and subsequent slave stations B When the sum of the number of times of reception by the line 1A and the number of times of reception by the sub line 1B is smaller than the number of times of transmission, the CPU 6 has a disconnection in at least the transmission line of the sub line 1B at a position between the slave stations B5 and B6. To judge.

(B) Confirmation of Abnormality of Reception Line and Identification of Abnormal Position Seen from Master Station A (B-1) First, from the master station A to each slave station B, from each slave station B to master station A To send the data of the number of transmissions to.

(B-2) In response to this, the transmission count data transmitted from each slave station B to the master station A is sent to the CP of the master station A.
Count by U6. Based on the counting result, the number of times of transmission from each slave station B and the number of times of reception for each slave station B recorded in the logging circuit 8 of the master station A are compared to confirm whether or not there is a line abnormality and check for any abnormality. Identify possible locations. Master station A
When the number of receptions from each slave station B by the main line 1A in 1 is equal to the number of transmissions from each slave station B to the master station A,
The CPU 6 determines that the main line 1A is normal. For example, when the number of receptions by the main line 1A from the slave stations B1 and B2 is equal to the number of transmissions and the number of receptions by the main line 1A from the slave station B after the slave station B3 is less than the number of transmissions, the CPU 6 determines that the slave station At the position between B2 and slave station B3, it is determined that at least the reception line of the main line 1A has a disconnection. In the slave stations B from the slave station B3 to the slave station B5, the number of receptions by the main circuit 1A and the sub circuit 1B are performed.
The sum of the number of times of reception by the mobile station B is equal to the number of times of transmission,
In the slave stations B 6 and later, when the sum of the number of times of reception by the main line 1A and the number of times of reception by the sub line 1B is smaller than the number of transmissions, the CPU 6 determines that the sub line is located at a position between the slave stations B5 and B6. It is determined that at least the reception line of 1B has a disconnection.

[0021]

According to the transmitting and receiving apparatus of the present invention, the main line and the plurality of child stations are commonly connected to each other by the main line and the sub line, and both the parent station and the plurality of child stations are connected. , Transmission sends the same data to both of the two lines, and detects an abnormality of the main line to each of the slave stations based on whether or not the transmission data from the master station matches a predetermined abnormal state. Since the detection unit and the reception switching unit that switches the reception line from the main line to the sub line in response to the detection output of the line abnormality detection unit are provided, even if the main line is disconnected, the reception line is changed to the main line. To automatically switch to the sub line, and the function of the device can be maintained thereafter.

In the transmitter / receiver, each of the slave stations is further provided with a recording means for recording the number of times of reception from the master station for each line, and the master station is provided with the number of transmissions from itself and the slave station. When the determining means for determining the position of the line abnormality based on the comparison with the number of times of reception for each line recorded by the recording means is provided, the abnormal position of the line can be automatically determined.

Further, in the transmitter / receiver, when the colors of the cables of the main line and the sub line are different from each other, connection mistakes can be eliminated in the connection work of both lines, and the work can be reliably performed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a transmission / reception device according to the present invention.

FIG. 2 is a block diagram showing configurations of a slave station and a master station of the transmitting / receiving apparatus according to the present invention.

[Explanation of symbols]

 A controller for overall management (master station) B controller (slave station) 1A main line 1B sub line 4 reception switching circuit 6 CPU 7 counter 8 logging circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04B 3/60 H04B 3/60

Claims (3)

[Claims] 1. A transmission / reception apparatus in which communication between a master station and a plurality of slave stations is performed through a line commonly connected between these stations, wherein the line is a main line and a sub line. In addition, both the master station and the plurality of slave stations transmit the same data to both of the two lines for transmission, and the transmission data from the master station matches a predetermined abnormal state in each of the slave stations. A line abnormality detecting means for detecting an abnormality of the main line based on whether or not the main line is detected, and a reception switching means for switching the receiving line from the main line to the sub-line in response to the detection output of the line abnormality detecting means. Characterizing transceiver device. 2. Each of the slave stations is further provided with recording means for recording the number of times of reception from the master station for each line, and the master station has a recording means of the number of transmissions from itself and the slave station. 2. The transmitting / receiving apparatus according to claim 1, further comprising: a determining unit that determines the position of the line abnormality based on a comparison with the number of times of line-by-line reception recorded by. 3. The color of the cables of the main line and the sub line are different from each other,
The transmission / reception device according to claim 1.