JPS6276839A - Data transfer control system - Google Patents

Abstract

PURPOSE:To attain efficient data transfer control by transferring a data with a phase in all frames except a phase in a specific frame when the participation from a node to a system is admitted. CONSTITUTION:In receiving an initial connection request packet, a node (master station) N00 transfers an approval packet admitting the participation to a node (slave station) N01. When the node N01 receives it, a switch control signal H is outputted and the data transfer in the phase of all frames except the n-th frame is attained. In the data transfer, the node N00 has the functions of a broadcasting system transferring the data transferred from the node (master station) to all nodes (slave stations) at the same time, a selecting system where the node (master station) sends a data to a specific node (slave station) and the polling system where a polling is sent to request a transmission data to the node (slave station) when the node (master station) has not transmission data. Thus, the data transfer with excellent efficiency is attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a data transfer control system between a node (master station) and a node (slave station) in a data link including a plurality of nodes connected in a dendritic manner. Regarding.

[Conventional technology]

In a network that covers a limited area, such as a LAN (Local Area Network), one node usually has multiple communication channels, and these channels are connected to other independent nodes. A star network is not used because it complicates routing control, and has a relatively simple structure and method.

A loop type network, a bus type network, a ring type network, etc. are used. In any network, when data is transferred between nodes, the destination and data are included in the message, and the node specified by the destination receives the message, or a common In the case of a message that includes a destination, all nodes receive it.

In star networks and loop networks, messages are once collected in a network control circuit and then transferred to each node, whereas in bus networks and ring networks, there is no special network control circuit. , manage the data output at each node.

An outline of typical data transfer control using a conventional method will be explained. For example, in a bus-type network, to check whether the data to be transferred can be sent onto the bus, the device first enters reception mode, performs a reception operation, and then checks whether a message is running on the bus. If the message is running, it continues receiving and waits until the source node of the message stops sending it. When it learns that there is no longer a signal to send, it sends its own data to the bus. The bus has wired-or logic for each node, so if more than one node goes into transmit mode, the signals on the bus will collide and become incorrect. Therefore, it is detected whether the signal on the bus is the same as the transmitted signal, and if the signal is the same, the transmitted data can be considered to have correctly traveled on the bus as a message. In other words, it can be assumed that the data sent by the sending node has been definitely received by the destination node. If they are not the same, it is assumed that there has been a collision, and the data is sent again by repeating the procedure of retrying the transmission, and the node that is in receive mode determines from among the messages on the bus that it is addressed to its own node, and Pick out only the correct ones. Furthermore, each time such a data transfer is performed, a separate window procedure ensures that the entire data string is correctly sent to the destination.

Further, in a loop type network, one of the nodes constituting the network controls data transfer of the entire network. This node sends out a command statement for controlling data transfer on a loop, and the other nodes once receive this command statement and send out the transmission data of the own node according to a predetermined procedure.

In addition, in a ring network, slots of a certain fixed length circulate on the loop, and each node can independently place a message in an empty slot, and a node in reception mode circulates on the loop. Picks up messages addressed to its own node from among the messages circulating.

These conventional methods require time required for each node to check whether the destination included in the message is addressed to its own node;
This method has the disadvantage that the time required for collision detection and processing after collision detection cannot be ignored, and efficient data transfer is not possible. However, in order to compensate for these drawbacks, loop networks have an arbitration function that controls nodes according to a predetermined priority among requests, so that multiple nodes do not request data transfer at the same time. , there is a circuit that controls data transfer while performing self-diagnosis for faults in the loop.

In addition to these methods, there is also the point-to-point method, which transfers data between two nodes, and the point-to-point method, in which two or more nodes are distributed to different devices, and a node (main node) that controls data transfer between each device is used. A multi-channel computer that transfers data between a station (station) and multiple nodes (slave stations) facing it.
Point method [Problem to be solved by the invention] In the conventional data transfer control method described above, the LA
When using a high-speed data transfer rate within one device or a single device, a loop network system having an arbitration function to control each node is efficient.

However, when constructing data links between nodes distributed in devices connected in a tree-like manner using this loop network method, there are the following drawbacks.

(1) In the loop type network system, reliability is low because if one node participating in the loop fails, the entire system stops functioning.

(2) Since the data link is loop-shaped, expandability (flexibility) is poor.

(3) Since it has an arbitration function, the cost increases.

(4) It is necessary to connect the control signals for each node to the end of each node distributed in a dendritic manner, which increases the number of interface signals.

An object of the present invention is to provide a data transfer control system that improves these drawbacks.

[Means for solving problems]

The present invention uses a frame that is a system synchronization signal in a data transfer control method for transferring data between a node (master station) and a plurality of nodes (slave stations) in a system including a plurality of nodes connected in a tree-like manner. means for synchronizing with the internal phase synchronization signal and defining a specific intra-frame phase assigned to each node (slave station); opening/closing means for separating and connecting each node (slave station) and the data link; a control means for controlling the opening/closing means based on the definition means and an instruction from the node (slave station), and for initially connecting each node (slave station) to the data link at the specific intra-frame phase. The system is characterized in that a node (main station) requests participation in the system, and when participation in the system is approved by a node (main station), data transfer is performed in all intra-frame phases except the specific intra-frame phase.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 2 and 3 are diagrams showing a state in which a plurality of nodes distributed in a dendritic manner in a plurality of devices using the data transfer control method of the present invention are connected in a multi-point manner.

In FIG. 2, device D1 has a node (master station) N00 and nodes (slave stations) NOI, NO2, device D2 has nodes (slave stations) NIO, Nil, and device D3 has nodes (slave stations) N12. The device D4 has a node (slave station) N13, and each of the nodes distributed in a tree is connected by a full-duplex communication line 1 that enables data transfer in both directions at the same time. It shows. In FIG. 3, device D1 is a node (master station) NOO and a node (slave station)
In the figure, where devices D2 to Dx each have two nodes (slave stations), only device 2 has node N.
03 and NO4), each of the nodes distributed in a dendritic manner is connected by a full-duplex communication line 1.

FIG. 1 is a block diagram showing the configuration of a device 1 having a node (main station) N00. The full-duplex communication line 1 includes a down data link 2, which is a data link from a node (master station) to a node (slave station), and an up data link 3, which is a data link from a node (slave station) to a node (master station). ,
The loopback control signal described later is the node (main station) N00.
It has a loopback control signal line 4 sent from.

The node (slave station) N01 is connected to the updater link 3 via the switch 5 and to the downdata link 6 via the switch 6. Node (slave station) N01
A control circuit 7 is attached thereto, and the opening and closing of the switches 5 and 6 are controlled by the control circuit 7. Similarly, node (
The slave station NO2 is connected to the updater link 3 via a switch 8 and to the downdata link 6 via a switch 9. A control circuit 10 is attached to the node (slave station) N02, and a switch 8.9 is connected to the control circuit 1.
0 controls its opening and closing.

The device D1 further includes an n-frame (η: integer) intra-frame phase counting circuit/m multi-frame (m: integer) counting circuit 11 (hereinafter, these two counting circuits will be referred to as phase counting circuits) that define the intra-frame phase of the system. It supplies an initial connection phase signal to the nodes (slave stations) NOI, NO2 and the control circuit 7.10, which will be described later. A loopback circuit 12 for looping back these data links is inserted into the down data link 2 and the up data link 3, and this loop back circuit is controlled by a control circuit 7.10. The device D1 further includes the other device D2. The configuration of D3... is a configuration in which the node (main station) N00 and the data link monitoring circuit 13 are not included in the device D1,
The rest of the configuration is the same as that in FIG. 1, so a description thereof will be omitted.

Next, the operation of each circuit will be explained using FIGS. 1 and 4. Note that FIG. 4 is a time chart showing the timing of initial connection of each node (slave station) to the updater link and the timing of loopback.

When the device D1 is powered on, the node (main station) NOO
performs an initialization operation on each node (slave station) prior to NOI and NO2, and prepares to receive an initial connection request packet transferred from each node (slave station) to the updater link 3. Node (slave station) N01 and node (slave station) N
02 also performs an initialization operation, and controls the respective switches 5, 6, 8.9 that interface with the down data link 2 and the up data link 3 by the control circuits 7, 10.
The circuit is opened by control signals Δ, B, C, and D from.

Figure 4(a) shows the multi-frame structure of the data to be transferred.
The frame synchronization signal E and the intra-frame phase synchronization signal F (FIG. 4(b)) are input to the phase coefficient circuit 11. The phase counting circuit 11, which counts up with the frame synchronization signal E, synchronizes the phase of the frame with the intraframe phase synchronization signal F. The n-th frame of the phase counting circuit 11 becomes an initial connection phase signal G (FIG. 4(C)) that generates an initial connection request packet for each node (slave station). This is a control signal that allows a node (slave station) to arbitrarily transfer data to the updater link 3 after the power is turned on or the system is started up to prevent data collision. This initial connection phase signal G is input to the nodes (slave stations) NOI and NO2 and the control circuit 7.10 in FIG.

When the node (slave station) N old reaches the phase of the nth frame of the first multiframe, it outputs a switch control signal H to the control circuit 7. The control circuit 7 logically ANDs the switch control signal H and the initial connection phase signal G, and outputs the switch enable signal and B to the switches 5 and 6, respectively. As a result, switches 5 and 6 are closed, node (slave station) N01 is connected to down data link 2 and up data link 3, and an initial connection request packet is transferred from node (slave station) N01 to node (main station) N00.

Upon receiving this initial connection request packet, the node (master station) N00 sends an acknowledgment packet to the node (slave station) N01 that allows the node (slave station) N01 to participate in the data link.
Transfer to old. When the node (slave station) NOI receives this acknowledgment packet, it outputs a switch control signal H, and data transfer becomes possible within the phase from the nth frame to the (n-1)th frame excluding the nth frame. In this data transfer, the node (master station) N00 uses a broadcasting method in which the data transferred by the node (master station) is simultaneously transferred to all nodes (slave stations), and a method in which the node (master station) transfers data to a specific node (slave station). ), and a polling method in which a node (master station) sends a poll when there is no data to send and requests data to be sent from a node (slave station). Data transfer using this method becomes possible.

FIG. 4(d) shows the relationship between the phase to which a node (slave station) is initially connected and the phase commonly used by all nodes.

The operation of node (slave station) N02 differs only in that the initial connection request packet is generated in the n-th frame of the first multiframe;
Since it is the same as 01, the explanation will be omitted.

Next, we will explain the function that self-diagnoses failures that occur in data links.

The node (master station) N00 transfers packet data to each node (slave station) by a broadcasting method or polling/selecting method, and receives packet data transmitted by a node (slave station) by polling. However, some kind of failure occurred and the node (slave station)
If there is no response within a certain period of time, it is determined that there is a failure, and the data links 2 and 3 and nodes (slave stations) are self-diagnosed. The node (master station) N00 outputs a loopback control signal J (FIG. 4(e)) to all nodes (slave stations) via the loopback control signal line 4. Each node (
The control circuit associated with the slave station inhibits the respective switch enable signals using this loopback control signal J, and opens the switches connected to the down data link 2 and the up data link 3. At the same time, the control circuit 7 sends a loopback permission signal K (FIG. 4(f)) to the loopback circuit at the same phase as the initial connection phase signal G, which is the phase signal of the nth frame of the predetermined 0th multiframe. Output to 12. A loopback circuit is provided for each device and can be controlled from all nodes (slave stations) distributed within the device. The loopback circuit 12 puts the down data link 2 and the up data link 3 into a loop state in response to this loop back permission signal. This is called loopback mode. FIG. 4(h)) shows the timing of this loopback mode. When the data link monitoring circuit 13 is in the loopback mode, the data link monitoring circuit 13 is connected to the node (
The state of the data links 2 and 3 is monitored based on the data link monitoring control signal M from the main station) N00, and a data link monitoring response signal N is returned to the node (main station) N00 under the control of the data link monitoring circuit 13.

The node (main station) N00 judges this response signal N and judges whether the data links 2 and 3 are good or bad.

Next, node (slave station) N02
A loopback permission signal L (FIG. 4 (g)) is output to the loopback circuit 12 at the frame phase to set the loopback mode. The node (main station) N00 determines the quality of the data links 2 and 3 using the same method as described above.

〔Effect of the invention〕

As explained above, according to the present invention, in a system consisting of nodes distributed in a dendritic manner, after power is turned on, each node (slave station) receives a predetermined system synchronization signal, ie, an intra-frame phase. A node (main station) that participates in a data link using a specific phase synchronized with a synchronization signal.
After approval, the data is formally transferred, so multiple nodes (slave stations) do not transfer data at the same time, preventing data collisions, eliminating the need for a circuit with an arbitration function, and reducing the number of nodes (master stations). Since data transfer can be performed only by control, efficient data transfer is possible.

Also, if any failure occurs on the data link,
Each node (slave station) is disconnected from the data link and puts the data link into loopback mode with the same phase synchronization as the above-mentioned intra-frame phase synchronization signal,
If the node (main station) is equipped with a function to judge whether the data link is good or bad, it will be possible to isolate the failure.
The reliability of the data transfer control system is improved because the fault location can be identified in a short time.

Furthermore, this data transfer control system has the advantage that nodes (slave stations) can be easily expanded without power interruption.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, and Figs. 2 and 3 are diagrams showing a state in which a plurality of nodes distributed in a dendritic manner are connected to two or more devices in a multi-point manner. , FIG. 4 is a time chart showing the timing of initial connection of each node to the updater link and the timing of loopback. ■ ・・・・・・・・・・・・・・・・・・ Full duplex communication circuit 2 ・・・・・・・・・・・・・・・・・・ Down data link 3 ・・・・・・・・・・・・・・・
・・・ Updater link 4 ・・・・・・・・・・・・
...... Loopback control signal lines 5, 6, 8
．． 9... Switch 7.10 ...... Control circuit 11
・・・・・・・・・・・・・・・・・・ Phase coefficient circuit 12 ・・・・・・・・・・・・・・・ Loopback circuit 13 ・・・・・・・・・・・・・・・
...Data link monitoring circuit NOO...
・・・・・・・・・ Node (main station) NOl, NO2・
...... Nodes (slave stations) A, B, C, D... Switch permission signal E ......
・・Frame synchronization signal F ・・・・・・・・・・・・
・・・・・・ Intra-frame phase synchronization signal G ・・・・・・
・・・・・・・・・・・・ Initial connection phase signal H, I
・・・・・・・・・・・・ Switch control signal J
・・・・・・・・・・・・・・・ Loopback control signal, L ・・・・・・・・・・・・ Loopback permission signal M ・・・・・・・・・・・・・・・・・・
・・ Data link monitoring control signal N ・・・・・・・・
...... Data link monitoring response signal 4th
figure

Claims (1)

[Claims] (1) In a data transfer control method in which data is transferred between a node (master station) and multiple nodes (slave stations) in a system that includes multiple nodes connected in a tree, frame means for synchronizing with a phase synchronization signal and defining a specific in-frame phase assigned to each node (slave station); opening/closing means for separating and connecting each node (slave station) and the data link; ), comprising a control means for controlling the opening/closing means based on the definition means and an instruction from the node (slave station), and initially connects each node (slave station) to the data link at the specific intra-frame phase. Make the node request to join the system (
A data transfer control method characterized in that when participation in the system is approved by a master station (main station), data is transferred in all intra-frame phases except the specific intra-frame phase.