JPH11215167A - Network system and data communication method in network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable each station in a network to obtain a transmission opportunity of a message data frame by adding information for controlling transmission of the message data frame on a message token frame. SOLUTION: Information for controlling transmission of a message data frame is added on a message token frame, a master station and a slave station are made to store information corresponding to them and to judge. That is, a master station A takes out information from a message transmission wait priority flag area 8 inside of the master station A in order to transfer the right to transmit the message data frame to the slave station, adds it to a message transmission wait priority flag area 42 and transmits it. Then, the master station A that receives a message token frame 40 which is returned by way of each of each of slave stations B to D stores message transmission wait flag information 42 in a message transmission wait priority flag 8 inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system for performing data communication by a token passing system, and more particularly, to a network system in which a plurality of stations connected to a network of a token passing system uniformly transmit message data. The present invention relates to a network system provided with an opportunity to transmit a frame.

[0002]

2. Description of the Related Art Token Passing
The scheme is a scheme in which a specific signal or frame called a token is circulated on a physical or logical ring to give and receive an access right to a transmission medium such as a network. The station that has issued the transmission request captures the circulating token, obtains the right to access the ring, and transmits a data frame such as a message. After transmitting the data frame or the like, a token is transmitted to pass the access right to a downstream station.

[0003] In the token passing method, if the token expires, it becomes impossible to transmit from the terminal. Therefore, the token disappearance and reproduction are monitored, and the token circulates for a certain time or more. Upon detecting that the station has disappeared, a master station that generates a new token by erasing a data frame or the like remaining on the transmission medium is required, and any station may have the function of this master station. There must be one master station at a time.

[0004] This token passing (Token Passin)
g) The master station and other slave stations of the system
They are sequentially connected to form a physical or logical ring, and each station has a repeat (regeneration relay) function. Each of the slave stations uses a FIFO (First in Firs) to transmit a bit sequence of a data frame such as a message transmitted from the upstream.
t out) register, reproduce it with a slight delay by the repeat function and send it to the downstream station, and at the same time recognize the address added to the data frame etc., copy the data frame addressed to the own station and store it in memory Take in.

Further, token passing (Token Pas)
Each station of the sing) system also has a function of rewriting the bit string while a data frame such as a message is stored in the FIFO register, and changes the token to a code indicating the head of the data frame, and then continuously transmits the data. The station indicated by the destination address of the data frame or the like can transmit the data frame or erase the data frame, and at the station indicated by the destination address of the data frame, updates the bit indicating that the data frame or the like has been copied and updates the data frame. It is possible to make the transmitting station recognize that the data frame has reached the destination station.

[0006] Such token passing (Token P)
Each station connected to the ring network that performs data communication by the assing method determines whether or not to transmit a data frame such as a message when receiving a token. Is subtracted from the actually measured token round time (time from the previous token reception to the current token reception) from the token round time in the network stored internally as, and the time obtained by the subtraction is There is known a method of determining that transmission of a message data frame is possible if the time is sufficient to transmit the message data frame, that is, if there is a remaining time to transmit the message data frame. . In this case, each station transmits a message data frame only when there is the remaining time.

[0007]

However, the conventional message data frame transmission method has the following problems.

For example, in a ring network composed of three stations A, B, and C, the tokens are turned in the order of A → B → C, and only one station is transmitted in one cycle of the token. If the token A round time is set such that transmission cannot be performed, if station A transmits a message data frame at the time of each token reception, stations B and C will be station A Until the transmission of the message data frame ends, the message data frame cannot be transmitted.

Further, in the above example, if a token round time is set such that all three stations A, B, and C can transmit a message data frame in one token round, the token 1 round The tour time is the time required for three stations to transmit a message data frame, and is longer by that amount, and whether each station transmits a message data frame when receiving a token differs from time to time. In each case, there may be a case where no message is transmitted, a case where only one station transmits a message data frame, a case where two stations transmit a message data frame, and a case where three stations transmit a message data frame. The time required for the token to make one round of the network is different, and the time for one round of the token is equal. Not a.

Therefore, when a token round time is set such that all three stations can transmit a message data frame, a specific frame having a cycle shorter than the token round time is transmitted, or a specific frame is transmitted at a certain fixed cycle. Unable to transmit frames.

[0011] An object of the present invention is to provide a network in which data communication is performed by the token passing method so that each station in the network can obtain a message data frame transmission opportunity evenly. An object is to provide each station on the network with an even transmission opportunity without disturbing the set communication cycle period even when the network connection configuration changes.

[0012]

According to a first aspect of the present invention, a master station for monitoring a network and generating and erasing a message token frame that makes a round in the network, and transmitting a message data frame by using the message token frame. In a network system having at least one slave station provided with an opportunity, the message token frame includes a message transmission waiting flag area indicating that at least one station in the network is in a message data frame transmission waiting state, A message transmission waiting priority flag area indicating a result of the message transmission waiting flag area obtained in one round of a message token frame;
Transmission means for transmitting and receiving frames such as control codes and message data frames to and from the network; a transmission data area, a reception data area, a transmission completion flag area indicating completion of transmission of the message data frame, and a message data transmission waiting flag area of the message token frame Storage means having a message transmission waiting priority flag area indicating that there is a station waiting for transmission of a message data frame on the network after obtaining the data of the other station connected to the network. A token frame management unit for managing a message token frame for enabling transmission of a data frame, and a control / arithmetic unit for controlling each of the units, wherein the slave station includes a control code and a message data. In front of frames such as frames Transmission means for transmitting and receiving to and from the network, storage means having a transmission data area, a reception data area, and a transmission completion flag area indicating the completion of transmission of the message data frame, and a control / arithmetic means for controlling the respective means, The control / arithmetic unit of each station that has received the message token frame stores the message in the received message token frame in the own station by using the data in the message transmission waiting priority flag area and the data in the transmission completion flag area in the own station. It is characterized in that it is possible to determine whether or not there is a right to transmit the message data stored in the transmission data area of the means.

The operation of the first invention is as follows (1). (1) (1) After turning on the power, each slave station initializes a message transmission completion flag inside each slave station.

(2) After turning on the power, the master station
The message transmission completion flag and the message transmission waiting priority flag in the master station are initialized. (3) In order to transfer the right to transmit the message data frame to the slave station, the master station transmits a message token frame to which internal transmission wait priority flag information is added.

(4) The slave station receiving the message token frame checks the message transmission waiting priority flag on the received message token frame,
If "0" indicates that no station on the network is waiting for transmission of the message data frame, the transmission completion flag inside the slave station is cleared to "0".

If the message transmission waiting priority flag on the received token frame is "1" indicating that any station on the network is waiting for transmission of the message data frame, the transmission inside the slave station is performed. The completion flag is not cleared to "0".

Thereafter, the transmission completion flag inside the slave station and the message data frame transmission request are checked. If the transmission completion flag is "0" and there is a message data frame transmission request, furthermore, It is checked whether there is a transmission time for the message data frame. If the transmission time is short, the transmission of the message data frame is performed, and after the transmission is completed, the transmission completion flag in the slave station is set to “1”. The right to transmit the message data frame to the next station by transmitting the token frame is transferred.

[0018] The same applies to the above-mentioned check of the transmission time. If the time for transmission is not enough, the message data frame is not transmitted or the transmission completion flag in the slave station is not changed before receiving. The right to transmit the message data frame is transferred to the next station by transmitting the message token frame by setting the message transmission waiting flag of the message token frame to “1”.

Further, when the transmission completion flag in the slave station and the transmission request of the message data frame are checked, if the transmission completion flag is "1", the reception is completed regardless of whether the transmission request of the message data frame is present or not. Even if the transmission completion flag is "0" and there is no message data frame transmission request, the received message token frame is transmitted as it is and the message data frame is transmitted to the time station. Transfer the right to send.

(5) The master station that has received the message token frame returned via each slave station updates the message transmission waiting flag information in the received message token frame with the message transmission waiting priority flag inside the master station. Store in area.

Thereafter, the same processing as that of the slave station (4) is performed. That is, the message transmission wait priority flag on the received token frame is checked, and if it indicates "0" indicating that no station on the network is waiting for transmission of the message data frame, the master station internal The transmission completion flag is cleared to "0".

If the message transmission waiting priority flag on the received token frame is "1" indicating that any station on the network is waiting for transmission of the message data frame, the transmission inside the slave station is performed. The completion flag is not cleared to "0".

Thereafter, the transmission completion flag and the message data frame transmission request in the slave station are checked. If the transmission completion flag is "0" and there is a message data frame transmission request, furthermore, Checking whether there is a message data frame transmission time or not is performed by checking one of the token frames stored in the master station.
The transmission is performed based on the fixed time during the tour and the actually measured token one round time. If the transmission time is sufficient, the message data frame is transmitted, and after the transmission is completed, the transmission completion flag in the master station is set to “1”. The right to transmit the message data frame to the next station by transmitting the token frame is transferred. The same applies to the above transmission time check. If the transmission time is insufficient, the message token received earlier without transmitting the message data frame or changing the transmission completion flag in the slave station is not performed. By transmitting the message token frame with the message transmission waiting flag of the frame set to “1”, the right to transmit the message data frame is transferred to the next station.

Further, when the transmission completion flag in the slave station and the transmission request of the message data frame are checked, if the transmission completion flag is "1", regardless of whether the transmission request of the message data frame is present or not, the reception is completed. Even if the transmission completion flag is "0" and there is no request to transmit a message data frame, the received message token frame is transmitted as it is, and the message data frame is transmitted to the next station. Transfer the right to send.

(6) According to the above (1) to (5), each station in the network sets the transmission completion flag to "1" when the own station can transmit, and the message token frame is first set to 1 Until all other stations waiting for transmission of the message data in the network detected during the tour can transmit, the transmission completion flag that has become “1” is not cleared to “0”. The right to transmit the message data is circulated to the multiple stations due to the circulation of the frame, and since the multiple stations transmit the message data in order, the opportunity to obtain the right to transmit the message data is sequentially turned to each station, and the message data is transmitted. Equalization of the opportunity to get the right to send is performed.

According to the second aspect of the present invention, a master station that monitors a network and generates and deletes a message token frame that makes a round in the network, and a message data frame transmission opportunity can be given by the message token frame. In a network system having at least one slave station, the master station manages a special message token frame transmitted to measure one round time in the network, A specific frame management means for sequentially transmitting specific frames in accordance with the set transmission cycle period; a reference message data frame having a data length of 1 byte addressed to the own station; Send time to As the time, the transmission reference time management means for transmitting the transmission reference time and the reference message token frame together with one round time to the other slave station in a broadcast frame, and the transmission time of the specific frame and the reference message data frame are stored. Storage means having a transmission time area, a reception time area for storing a reception time, a transmission reference time area for storing the transmission reference time, and a current cycle time area for storing a transmission cycle interval of the specific frame; The slave station has a specific frame period measuring unit for obtaining a transmission cycle period of the specific frame from a reception interval of the specific frame received, and a transmission reference time received from the master station. A transmission reference time area for storing the reception time area for storing the reception time of the specific frame; A memory means having a current cycle time domain for accommodating a periodic interval of a constant frame, wherein a control and operation means for performing control of each unit,
The control / arithmetic unit of each station that has received the normal message token frame, based on the content stored in each of the storage units in each station, calculates the difference between the reception time of the specific frame and the time of receiving the message token frame. The message data frame is transmitted within the periodic interval according to the time, one round time of the reference message token frame, the transmission reference time, and the transmission time of the message data frame calculated from the data length of the reference message data frame. It is characterized in that it is determined whether or not it is possible.

The operation of the second invention is as follows (2). (2) (1) The master station that detects a change in the connection configuration on the network transmits a specific frame, and further transmits a special message at an arbitrary time as soon as possible after the transmission of the specific frame within the transmission cycle of the specific frame. At the same time as transmitting the token frame, the transmission time is stored.

(2) Each slave station receiving the special message token frame does not transmit a message data frame, and transmits a token to the next station without transmitting a message data frame when a normal message token frame is received. After the transmission of the token is delayed by the time required to transfer the special message token, the received special message token frame is transmitted.

(3) The master station that has received the special message token frame returned via each slave station determines the message under the new connection configuration based on the received time and the transmission time saved at the time of transmission. One cycle time of the token frame is obtained, and the token one cycle time is stored in the token one cycle time area of the storage unit.

(4) Next, in order to obtain a transmission reference time, a reference message data frame for the own station with the address of the own station as the destination address and the length of the data portion as 1 byte of the reference is transmitted. The transmission time is stored in the storage unit.

(5) The master station that has received the reference message data frame for its own station that has returned via each slave station uses the reception time at which the message data frame was received and the transmission time stored at the time of transmission. A transmission reference time required for transmission of one byte under the new connection configuration is obtained and stored in a transmission reference time area.

(6) Next, at the master station, the transmission reference time obtained at (5) and the token round time obtained at (3) are added to the broadcast frame to each slave station and transmitted. . (7) Each slave station receiving the broadcast frame to which the transmission reference time and the token round time are added stores them in the transmission reference time area and the token round time area in the storage unit.

(8) When the slave station receives a specific frame sent from the master station, the slave station stops and restarts the period measurement timer provided in the specific frame period measurement unit or the time measurement unit. And stores the timer value in the current cycle time area of the storage unit.

(9) Thereafter, each of the slave stations receiving the normal message token frame receives the specific frame stored in the reception time area based on the storage content of the current cycle time area in the storage unit. The time of the difference between the time and the time when the message token frame was received,
By the transmission time of the message data frame calculated from the token one round time, the transmission reference time, and the data length of the message data frame, a message data frame that can be transmitted within the time stored in the current cycle time area is determined. A transmission time is calculated to determine whether the message data frame can be transmitted. (10) The master station that has received the normal message token frame stores the transmission time of the specific frame stored in the transmission time area and the message token frame based on the stored content of the current cycle time area in the storage unit. Stored in the current cycle time area according to the time difference between the transmission times, the one round time of the message token frame, the transmission time of the message data frame calculated from the transmission reference time and the data length of the message data frame. The transmission time of a message data frame that can be transmitted within the set time is calculated, and it is determined whether the message data frame can be transmitted.

By performing the operations (1) to (10) of the above (2), the following operations can be performed in the master station and the slave stations. The master station calculates the remaining time during which message data can be transmitted when a message token frame is received within a fixed period according to the system configuration, and transmits the time required to transmit the data length of the message data frame to be transmitted this time. It is calculated from the reference time, and by comparing the calculated results, it is determined whether or not transmission of the own station message data frame is possible.

Further, the master station transmits the message token frame to the slave station at the present time within the fixed period, and transmits a message token frame to the slave station. By transmitting the message data frame of the determined minimum number of bytes and comparing the time until the message token frame returns to the master station again, when the message token frame is transmitted to the slave station from now on, The message token frame can be transmitted after determining whether transmission is possible without disturbing the fixed period.

On the other hand, the slave station gives the message transmission based on the current cycle time stored in the storage unit and the elapsed time from the reception time of the specific frame stored in the storage unit to the reception time of the message token frame. By calculating the remaining time, and further calculating the time required for transmitting the message data frame from the stored transmission reference time from the data length of the message data frame to be transmitted, and comparing the two, the own station can determine It is possible to determine whether to transmit a message data frame to be transmitted.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of an embodiment when a master station A and slave stations B to D according to the first invention are configured in a ring network.

The station addresses on the network are as follows: the master station is station A, the first slave station is station B,
The second slave station is station C, and the third slave station is station D.
Includes a 1-bit message transmission waiting flag 41 and a 1-bit message transmission waiting priority flag 42, which are passed in the order of station A, station B, station C, station D, and station A. I do.

At present, all the stations are initialized after power-on. (i) The master station A transfers the right to transmit the message data frame to the slave station,
The information is extracted from the internal message transmission waiting priority flag area 8 and added to the message transmission waiting priority flag area 42 of the message token frame 40 and transmitted.

(Ii) The slave station B that has received the message token frame checks the message transmission waiting priority flag 42 on the received message token frame 40. If “0”, the internal transmission completion flag 27-
Initialize 1 and clear to "0". If the priority flag 42 is "1", the state of the transmission completion flag 27-1 in the slave station B is maintained as it is. next,
It is checked whether the internal transmission completion flag 27-1 is "0" and whether or not there is a message data frame transmission request. If there is a transmission request, it is determined whether there is further message data frame transmission time. The remaining time is obtained from the contents of the fixed time area 26 of the token B inside the station B and the actually measured token one round time (the time from the reception of the previous message token frame to the reception of the current message token frame).

If there is remaining time, the message data frame is transmitted, and after the transmission is completed, the transmission completion flag 27-1 inside the slave station B is set to "1". Then, by transmitting the previously received message token frame 40, the right to transmit the message data frame to the next station (slave station C) is transferred.

Alternatively, if the transmission completion flag 27-1 inside the slave station B is "0" and there is a request to transmit a message data frame, and there is no time, the message transmission of the previously received message token frame 40 is performed. The message token frame 40 in which the wait flag 41 is set to “1” is transmitted.

When the transmission completion flag 27-1 inside the slave station B is "1" or when there is no request to transmit a message data frame, the previously received message token frame 40 is transmitted as it is. so,
The right to transmit the message data frame is transferred to the next station (slave station C).

Thereafter, in each of the slave stations C and D, the same processing as in the slave station B is repeated. (Iii) Upon receiving the message token frame 40 returned via each of the slave stations B, C and D, the master station A changes the message transmission waiting flag information 42 on the received message token frame to the internal message transmission waiting state. It is stored in the priority flag area 8. Thereafter, the same processing as that of the slave stations B, C, and D is performed. That is, the message transmission waiting priority flag 42 on the received message token frame 40 is checked.
The internal transmission completion flag is cleared to "0".

If the message transmission waiting priority flag 42 is "1", "0" is not cleared to the transmission completion flag area 7 inside the master station A, and the current state is maintained. Next, the transmission completion flag area 7 inside the master station A is set to “0”.
And confirms the message data frame transmission request, and if there is a transmission request, determines whether there is a message data frame transmission time or whether the fixed time during the token 1 round inside the master station A and the actually measured token 1 round time To obtain the remaining time. If the remaining time is shorter than the message data frame transmission time, the message data frame is transmitted, and after the transmission is completed, the transmission completion flag 7 in the master station A is set to “1”. Then, by transmitting the previously received message token frame 40, the right to transmit the message data frame is transferred to the next station.

Alternatively, if the transmission completion flag 7 in the master station A is "0" and there is a request to transmit a message data frame, and the remaining time is less than the transmission time of the message data frame, the reception is performed first. The message token frame 40 with the message transmission waiting flag 41 of the message token frame 40 set to “1” is transmitted.

When the transmission completion flag 7 in the master station A is "1" or when there is no request to transmit a message data frame, no message data frame is transmitted.

By performing the above operations (i) to (iii), all stations on the network can transmit message data frames in order and evenly.

FIG. 2 is a diagram showing the configuration of an embodiment of the master station A according to the present invention. The transmission unit 1 is connected to a network and transmits and receives various frames such as a message frame and a data frame.

The time measuring unit 2 measures the transmission time and reception time of various frames such as a message token frame, the round trip time between them, and the transmission interval and reception interval of the same type of frame.

The storage unit 3 stores various data and set values relating to time and time, messages to be transmitted and received, flags indicating states and conditions, and the like, and details thereof will be described below.
The transmission data area 4 is an area for storing message data and the like transmitted from the master station A to the other slave stations B to D and transmitted to the network.

The reception data area 5 is an area for storing message data and the like received from other slave stations B to D to the master station A via the network. The token cycle time area 6 is an area in which the time required for the message token frame 40 that gives each station A to D the right to transmit message data to make a single round of the network in the current network configuration is stored. .

The transmission completion flag area 7 changes from “0” to “1” when the message data waiting for transmission in the transmission data area 4 is transmitted to the network as a result of receiving the message token frame 40. This area stores a transmission completion flag indicating that transmission has been completed.

Message transmission waiting priority flag area 8
Stores the contents of the message transmission waiting priority flag indicating that at least one of the stations of the network is waiting for transmission of the message data frame collected by the message token frame that has made one round of the stations of the network last time. Area.

The transmission time area 9 is an area for storing the transmission time of various frames as data for calculating the remaining time of the cycle and the transmission time of the message data frame when the transmission cycle of the message token frame is fixed. It is.

The reception time area 10 stores the reception time of various frames as data for calculating the remaining time of the transmission cycle and the transmission time of the message data frame when the transmission cycle of the message token frame is a fixed value. Area.

The transmission reference time area 11 is an area for storing a time required for 1-byte message data transmitted on the current network to make one round of the network. The current cycle time area 12 is an area for storing a time interval of a frame transmission cycle for determining a message data frame transmission cycle of each station in the current network.

The control / arithmetic unit 13 controls each unit of the master station A, controls data exchange, and calculates time and time. The token frame management unit 14 transmits a new message token frame at regular intervals or at an arbitrary timing via the transmission unit 1 or transmits a message token frame that has made one round of the network after transmission.
Is a management unit that performs necessary processing by receiving the information via the Internet.

The specific frame management unit 15 is a management unit that transmits a new specific frame to the network at regular intervals via the transmission unit 1 and sets the transmission interval as a transmission cycle period.

The transmission reference time management unit 16 creates and transmits a 1-byte reference message data frame for the own station via the transmission unit 1 and transmits the transmission time to the transmission time area 9.
The transmission reference time is set in the transmission reference time area 11 from the time when the reference message data frame is received in one round of the network and the stored transmission time, and all broadcasts in the network are sent by the broadcast frame. This is a management unit that notifies the slave station of the transmission reference time together with the token one round time.

FIG. 3 shows slave stations B to D according to the present invention.
FIG. 2 is a diagram showing a configuration of one embodiment. The transmission unit 21 is connected to the network 35 in the same manner as the transmission unit 1 of FIG. 2, and performs transmission and reception of various frames such as a message frame and a data frame.

The time measurement unit 22 measures the transmission time and reception time of various frames such as a message token frame, the round-trip time therebetween, and the transmission interval and reception interval of the same type of frame, similarly to the time measurement unit 2 of FIG. I do.

The storage unit 23 stores various data and set values relating to time and time, messages to be transmitted and received, flags indicating states and conditions, and the like, similar to the storage unit 3 in FIG. Some are different. The details are described below.

The transmission data area 24 is the same as the transmission data area 4 in FIG. 2 except that the station in which this area exists is not the master station A but the slave stations B to D. To D, where the transmission destination is usually one of the remaining slave stations B to D and is destined to the master station A, and is an area where message data and the like to be transmitted and output to the network are stored.

On the other hand, the reception data area 25 normally contains, from the master station A, one of the remaining slave stations BD.
This is an area in which message data and the like received via the network to any of the slave stations B to D as the own station are stored.

The token one round time area 26 is similar to the token one round time area 6 in FIG. 2 in that the message token frame which gives each station the right to transmit message data in the current network makes one round of the network. Although the required time is stored in the area, the stored token round time depends on the amount of messages set within the fixed cycle period when a message token frame is transmitted every fixed cycle period. The transmission period is stored as one token round time with the added transmission period.

As in the transmission completion flag area 7 of FIG. 2, the transmission completion flag area 27 indicates that the message data waiting to be transmitted in the transmission data area 24 has been transmitted to the network by receiving the message token. This is an area where a completion flag is stored.

The reception time area 28 is the same as the reception time area 10 in FIG. 2 when the transmission cycle of the message token frame is a fixed value and the remaining time of the cycle and the transmission time of the message data frame are calculated. This is an area for storing reception times of various frames transmitted to obtain data.

The transmission reference time area 29 is an area for storing the time required for transmitting 1-byte reference message data in the current network, similarly to the transmission reference time area 11 in FIG. Unlike the transmission reference time area 11, the transmission reference time is usually notified from the master station A by a broadcast frame.

The current cycle time area 30 is an area for storing a time interval of a cycle in which a specific frame for determining a transmission cycle is received in the current network, similarly to the current cycle time area 12 in FIG.

The specific frame period measuring unit 31 corresponds to the specific frame managing unit 15 in FIG. 2. The specific frame managing unit 15 in FIG. 2 manages the period of the specific frame to be transmitted. The cycle management unit 31 measures the cycle of the received specific frame together with the time measurement unit 22.

The control / arithmetic unit 32 controls each unit of any one of the slave stations B to D, which is its own station, controls the exchange of data, and controls time and time, similarly to the control / arithmetic unit 13 of FIG. The time is calculated.

FIG. 4 is a flowchart illustrating the operation of the master station A according to the embodiment of the present invention. In step S1, the power of the master station A is turned on.

In step S2, when the power of the own station is turned on, the message transmission completion flag area 7 and the message transmission waiting priority flag area 8 in the storage unit 3 are initialized, and both areas are set to "0". Becomes This state means that, at present, there is no message data waiting to be transmitted to the own station, and there is no message data waiting to be transmitted to any other station on the network.

Step S3 is the transmission of the first message token frame after power is supplied to the own station, and the right to transmit message data is transferred to the slave station by this transmission. A message transmission waiting flag 41 and a message transmission waiting priority flag 42 are added to the message token frame. In this case, both flags are "0" in the initial state.

Step S4 is the reception of the message token frame that has returned to its own station after making a round of the network. In step S5, the information of the message transmission waiting flag obtained while the received message token frame makes one round of the network is stored in the message transmission waiting priority flag area 8 of the time station (master station). Is initialized.

In step S6, it is confirmed whether or not the own station has a priority for transmitting the message data. The message transmission waiting priority flag of the received message token frame is "0", that is, It checks if any station in the network is waiting for message transmission. In this case, a station that is not waiting for message transmission means that, as described later, it is possible to temporarily transmit message data and receive the priority of transmitting the next message data until the priority goes round. Including stations that cannot.

If the message transmission waiting flag of the message token frame is “0”, that is, if there is no station waiting for message transmission in the network, or if the transmission waiting priority has made a round of each station in the network, the self Proceeding to step S7 for initializing the message transmission completion flag area 7 in the station (master station), if the message transmission waiting flag is "1", that is, if there is a station waiting for message transmission in the network, Step S8 for checking whether the station waiting for the message transmission is the own station.
Proceed to.

In step S7, the message transmission priority flag in the message token frame indicates that there is no station waiting for transmission of message data in the network, that is, that there is a priority for transmitting the next message data. Then, the message transmission completion flag area 7 in the own station is initialized to enable transmission of the next message data.

In step S8, in response to the message transmission waiting priority flag of the message token frame indicating that there is a station waiting for transmission in the network, the own station further has the right. In order to confirm whether or not the message transmission completion flag area 7 in the own station is "0", it is confirmed. If the message transmission completion flag area 7 is “0”, it means that the target message data has not been transmitted yet and that the own station has a priority, so the message data stored in the transmission data area 4 To the next step S9 in order to transmit. If the message transmission completion flag is "1", it means that the own station does not have priority, and therefore, step S1 for transmitting the message token frame to the next station.
Proceed to 4.

In step S9, the previous station S7 and step S8 determine that there is a request to transmit a message data frame to be actually transmitted because the own station has a priority to transmit message data. I do. This confirmation may be made by confirming whether the message data is stored in the transmission data area 4 or by providing a flag or the like separately from the storage of the message data. If there is a message data frame transmission request, the next step S1 for confirming the message data frame transmission time
Go to 0. If there is no message data frame transmission request, it means that there is no message data to be actually transmitted even though there is a priority, and the process proceeds to step S14 for transmitting a message token frame to the next station.

In step S10, before transmitting the message data frame, it is confirmed whether or not the message data frame to be transmitted this time can be transmitted within one round of the message token frame. In this case, the message token one round time actually measured by the token frame management unit 14 and the time measuring unit 2 is calculated from the fixed value of the message token frame one round time stored in the token one round time area 6. Judge whether there is remaining time or not. If there is remaining time, the process proceeds to step S11 of transmitting a message data frame. If there is no remaining time, transmission waits, so that the process proceeds to step S12 in which the message transmission wait flag in the received message token frame is set to "1".

In step S 11, the transmission of the message data frame stored in the transmission data area 4 of the storage unit 3 is performed via the transmission unit 1. Step S12 is a case in which the transmission of the message data is attempted, but the transmission was not completed due to the lack of the transmission time of the message data frame. The message transmission waiting flag in the message token frame to be set to “1”.

Step S13 is processing after transmission of the message data frame. Since the message data frame can be transmitted once by the own station (master station) by the processing of step S11 of the previous step, the priority of the message data transmission received after that goes through each station of the network once. Until it is necessary to transfer to another station.
Here, the own station's message transmission completion flag is set to "1", indicating that the own station's priority has been used when a future message token frame is received.

At step S14, the message token frame 40 in which the data of the message transmission waiting priority flag area 8 of the own station is stored in the message transmission waiting priority flag 42 of the message token frame 40 is transmitted. The transmitted message token frame 40 makes a round of the network and is received in step S4, and the processing from step S4 to step S11 is repeated.

FIG. 5 is a flowchart illustrating the operation of one of the slave stations B to D according to the embodiment of the present invention. In step S21, the power of any one of the slave stations B to D is turned on.

In step S22, when any one of the slave stations B to D is powered on, the message transmission completion flag area 27 in the storage unit 23 is initialized and the area becomes "0". . This state means that there is no message data waiting to be transmitted to the own station at present.

Step S23 is the reception of the message token frame that has arrived at the own station via the network. A step S24 checks whether or not the own station has a priority to transmit the message data. The message transmission waiting priority flag of the received message token frame is "0", that is, whether or not the Check if there are any stations waiting for message transmission. Note that, in this case, the stations that are not waiting for message transmission include stations that can transmit message data once and do not receive the priority until the priority goes around once as described later. If the message transmission waiting flag of the message token frame is "0", that is, if there is no station waiting for message transmission in the network or the transmission waiting priority has made one round, the message transmission completion flag area 27 in the own station is set. Proceeding to step S25 for performing initialization, if the message transmission waiting flag is "1", that is, if there is a station waiting for message transmission in the network, the station waiting for message transmission is its own station. The process proceeds to step S26 for confirming whether or not the process is complete.

In step S25, the message transmission priority flag in the message token frame indicates that there is no other station waiting for transmission of the message data in the network, that is, the priority of transmitting the next message data is not determined. In response to the presence of the own station, the message transmission completion flag area 27 in the own station is initialized to enable transmission of the next message data.

In step S26, in response to the message transmission priority flag in the message token frame indicating that there is a station waiting for transmission in the network, the own station further has the right. In order to confirm whether or not the message transmission completion flag area 27 in the own station is “0”, it is confirmed. If the message transmission completion flag area 27 is “0”, it means that the own station has priority, and the process proceeds to the next step S27 to transmit the message data stored in the transmission data area 24. If the message transmission completion flag is "1", it means that the own station has no priority, and the process proceeds to step S32 for transmitting the message token frame to the next station.

Step S27 is the same as step S2
In the steps up to 6, since it has been found that the own station has the priority of transmitting the message data, it is confirmed whether or not there is a request to transmit the message data frame to be actually transmitted. This confirmation may be made by confirming whether the message data is stored in the transmission data area 24 or by providing a flag or the like separately from the storage of the message data. If there is a message data frame transmission request, the process proceeds to the next step S28 for transmitting the message data frame. If there is no request to transmit a message data frame, it means that there is no message data to be actually transmitted even though there is a priority, so that step S for transmitting the message token frame to the next station is performed.
Proceed to 31.

In step S28, before transmitting the message data frame, it is confirmed whether or not the message data frame to be transmitted this time can be transmitted within one round of the message token frame. In this case, there is a remaining time obtained by subtracting the message token one round time actually measured by the time measuring unit 22 from the message token frame one round time set value which is a fixed value stored in the token one round time area 26. Or not. If there is remaining time, the process proceeds to step S29 for transmitting a message data frame. If there is no remaining time, transmission waits, so the process proceeds to step S30 in which the message transmission wait flag in the received message token frame is set to "1".

In step S29, the transmission of the message data frame stored in the transmission data area 24 of the storage unit 23 is performed via the transmission unit 21. Step S30 is to transmit message data, but when there is no transmission time for the message data frame, the network 35 is used to inform other stations that the own station is waiting for transmission.
Is performed to set the message transmission waiting flag in the message token frame to be transmitted to "1".

Step S31 is processing after transmission of the message data frame. Since the message data frame was once transmitted by the own station by the processing of the previous step, the priority of the message data transmission received thereafter must be transferred to another station until the priority goes around the network 35 once. is there. Here, the own station's message transmission completion flag is set to "1", indicating that the own station's priority has been used when a future message token frame is received.

In step S32, the message token frame received in step S23 is transmitted. The message token frame is sent out to the network, the own station enters a message token frame waiting state, and returns to step S24. When a new message token frame is received, steps S24 to S32 are performed.
The processing up to is repeated.

FIG. 6 shows that the cycle of the transmission cycle is changed from the cycle of the message token frame shown in FIG. 1 to a fixed cycle of the specific frame, and the remaining time within the cycle and the length of the message data to be transmitted are shown. Therefore, a diagram (timing chart) for explaining the second embodiment for clarifying the determination as to whether or not transmission is possible within a period
It is. The setting conditions of each station that are not specified are the same as those in FIG.

(A) Now, the master station A, which has detected a change in the connection configuration on the network, sends the specific frame 50-1,
The transmission of 51-1 is sequentially performed according to the transmission cycle period, and the transmission time is stored.

(B) In order to determine one round time of the message token frame itself at an arbitrary time as early as possible within the transmission cycle period after the transmission of the specific frame 50-1,
The transmission time is stored at the same time as the transmission of the special message token frame 60-1.

(C) Special message token frame 6
The slave station B that has received 0-2 does not transmit the message data frame, and the time required to transfer the token to the next station without transmitting the message data frame when a normal message token frame is received. The transmission of the received special message token frame 60-2 is performed after delaying the transmission of the token.

(D) The master station A, which has received the special message token frame 60-5 returned via each of the slave stations B, C, D, determines the reception time and the transmission time saved at the time of transmission. The one round time (Tl) of the message token frame under the new connection configuration is obtained and stored in the token one round time area 6 of the master station A.

(E) Next, the master station A transmits a message data frame 70-1 for its own station having a 1-byte data part length with its own station address as the destination address, in order to obtain the transmission reference time (T2). And save the sending time at the same time.

(F) The master station A, which has received the message data frame 70-5 for its own station which has returned to the master station A via each of the slave stations B, C, D, stores the reception time and the transmission time. Transmission reference time (T2) required for 1-byte transmission under a new connection configuration based on the set transmission time
And store it in the transmission reference time area 11 of the master station A.

(G) Then, the master station A transmits the token 1 of the message token frame obtained in the above (D).
The traveling time (Tl) and the transmission reference time (T
2) is added to the broadcast frame 80-1 and transmitted.

(H) A broadcast frame 80 to which a token round time (T1) and a transmission reference time (T2) are added.
-2, 80-3, 80-4, each slave station B receiving
C and D store it in the internal transmission reference time area 29.

(I) The master station A transmits the specific frame 50
When the specific frame 51-1 is transmitted after the transmission cycle period (T) by transmitting −1, the time is stored in the current cycle time area 12 as the transmission cycle period (T).

(J) Further, each of the slave stations B, C, and D receives a specific frame 51-2, 5
When 1-3 and 51-4 are received, the internal period measuring timer in the internal specific frame period measuring unit 31 or the time measuring unit 22 is stopped, and the timer value is set as the transmission cycle period (T) in the current period time region 30. At the same time, the period measurement timer is restarted.

By performing the above operations (A) to (J), the master station A receives the message token frame 90-1 within the transmission cycle period (T) corresponding to the system traffic. The remaining time (t5) during which the message can be transmitted and the time required for transmitting the message data frame with respect to the current transmission data length are calculated from the token 1 round time (Tl) and the transmission reference time (T2), and are compared to be transmitted. It becomes possible to determine whether or not the own station's message data frame can be transmitted within the remaining time of the cycle period.

Further, the remaining time (tl) and (t5) given to the current message transmission within the transmission cycle period (T) and the slave receiving the message token frame 90-1 transmitted from the master station A. In any one of the stations B, C and D, the message data frame 1 having the minimum number of bytes determined by the system
00, and the time until the master station A receives the message token frame 90-6 again is compared. Even if a message token frame is transmitted to the slave station, the transmission cycle period (T) is disturbed. It can be determined whether or not transmission is possible without any problem.

The slave stations B, C, and D transmit the current cycle time (transmission cycle cycle (T)) and the specific frames 50-2, 50-3 when receiving the message token frames 90-2, 90-4, and 90-5. , 50-4, and the remaining time (t2), (t2) given to the message transmission from the elapsed time from the reception.
3) and (t4) are calculated, and the time and the time required for transmitting the message data frame with respect to the current transmission data length are defined as token 1 round time (T1) and transmission reference time (T2).
By calculating and comparing, it is possible to determine whether to transmit the own station message data frame.

Although the above embodiment has been described as a token ring network, the present invention is not limited to the above token ring network, and is applicable to a token bus network. can do.

[0112]

According to the present invention, transmission of a message data frame on a message token frame that transfers the right to transmit a message data frame is controlled in a ring network system including a master station and a slave station. For example, by adding 2-bit information and storing the corresponding information in the master station and the slave station and making a judgment, each station connected on the network can obtain a message data frame transmission opportunity equally. It is possible to avoid problems such as concentration of message transmissions at specific stations and congestion caused by the trend order of tokens, the frequency of transmission of message data frames that differ from station to station, or the time required for one round of tokens. Will be able to do it.

This can further contribute to making the design of the message communication in the system design easy and easy to grasp. Furthermore, by preparing a specific frame, a special message token frame and a message data frame for measuring the transmission reference time, and storing and judging the corresponding information in the master station and the slave station, the communication cycle period is not disturbed. In addition, each station can obtain a message communication opportunity equally.

Thus, for example, in a network system for controlling or measuring an FA or the like, a certain I / O device on the network can be transmitted at a high speed and at a constant period regardless of the frequency of message communication or the amount of data. Data can be read and written.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a first embodiment in a network.

FIG. 2 is a block diagram illustrating a schematic configuration of a master station.

FIG. 3 is a block diagram illustrating a schematic configuration of a slave station.

FIG. 4 is a flowchart showing a schematic operation of a master station.

FIG. 5 is a flowchart showing a schematic operation of a slave station.

FIG. 6 is a timing chart of a second embodiment in which a transmission cycle period is fixed.

[Explanation of symbols]

 1, 21 Transmission unit 2, 22 Time measurement unit 3, 23 Storage unit 4, 24 Transmission data area 5, 25 Receive data area 6, 26 Token one round time area 7, 27 Transmission completion flag area 8 Message transmission waiting priority flag Area 9 Transmission time area 10, 28 Reception time area 11, 29 Transmission reference time area 12, 30 Current cycle time area 13, 32 Control / calculation section 14 Token frame management section 15 Specific frame management section 16 Transmission reference time management section 31 Specification Frame period measurement unit 40 Message token frame 41 Message transmission waiting flag 42 Message transmission waiting priority flag

Claims (8)

[Claims] 1. A master station for monitoring a network and generating and erasing a message token frame that makes a round in the network, and at least one slave station provided with a transmission opportunity of a message data frame by the message token frame. In the network system, the message token frame includes a message transmission waiting flag area indicating that at least one station in the network is in a message data frame transmission waiting state, and the message token frame obtained in one round of the previous message token frame. The master station has a message transmission waiting priority flag area indicating a result of the message transmission waiting flag area, and the master station includes: a transmission unit for transmitting / receiving a frame such as a control code and a message data frame to / from the network; There is a station waiting for transmission of a message data frame on the network by obtaining data of a reception data area, a transmission completion flag area indicating completion of transmission of the message data frame, and data of the message data transmission waiting flag area of the message token frame. Storage means having a message transmission wait priority flag area indicating that a message data frame is to be transmitted, and a token frame management means for managing a message token frame for enabling another station connected on the network to transmit a message data frame. And a control / arithmetic unit for controlling each of the units. The slave station includes a transmission unit for transmitting / receiving a frame such as a control code or a message data frame to / from the network, a transmission data area and a reception data area. And message data frame transmission Storage means having a transmission completion flag area indicating completion, and control / arithmetic means for controlling each of the means, wherein the control / arithmetic means of each station receiving the message token frame stores the The data of the message transmission waiting priority flag area, and the data of the transmission completion flag area in the own station,
A network system capable of determining whether or not there is a right to transmit message data stored in a transmission data area of a storage unit in its own station. 2. A message transmission waiting flag area and a message transmission waiting priority flag area in the message token frame are each 1 bit, and a total of information added to the message token frame is 2 bits. The network system according to claim 1, wherein 3. When the master station or the slave station has a right to transmit the message data frame, a signal indicating that message data exists in a transmission data area of the storage means or a signal of the stored message data is transmitted. 2. The network system according to claim 1, wherein a signal indicating a transmission request or a signal indicating waiting for transmission of stored message data is detected to confirm the presence of message data to be transmitted. 4. The master station and the slave station each include a time measuring unit for measuring a transmission time and a reception time of a frame to be transmitted and received and a round time of the frame, and a message token frame in a storage unit of each station. Each station has a token one round time area for storing a set time to go around, and the control / calculation means of each station calculates data such as the time obtained by the time measuring means, and obtains the token one round time. 2. The method according to claim 1, wherein it is determined whether the time for transmitting a message data frame for transmitting the message data stored in the storage means is insufficient within one round of the token stored in the area. Network system. 5. A master station for monitoring a network and generating and erasing a message token frame that makes a round in the network, and at least one slave station provided with a transmission opportunity of a message data frame by the message token frame. In the network system, the master station may include a special message token frame management unit that manages a special message token frame transmitted for measuring one round time in the network, and a transmission cycle period set to a constant period in the network. A specific frame management means for sequentially transmitting a specific frame; a reference message data frame having a data length of 1 byte addressed to the own station;
Transmission reference time management means for measuring a cycle time and using the one cycle time as a transmission reference time to transmit to the other slave station in a broadcast frame together with the transmission reference time and one cycle of the reference message token frame; And a transmission time area storing the transmission time of the reference message data frame, a reception time area storing the reception time, a transmission reference time area storing the transmission reference time, and a current cycle time storing the transmission cycle interval of the specific frame. A storage unit having an area; and a control / arithmetic unit for controlling each of the units, wherein the slave station measures a specific frame period to obtain a transmission cycle period of the specific frame from a reception interval of the received specific frame. Means, a transmission reference time area containing a transmission reference time received from a master station, and reception of the specific frame. A storage unit having a reception time area for storing the time and a current cycle time area for storing the cycle interval of the specific frame; and a control / calculation means for controlling each of the units, and receives a normal message token frame. The control / calculation means of each station, based on the contents stored in each of the storage means in each station, the time of the difference between the reception time of the specific frame and the time of receiving the message token frame, and the reference message token It is determined whether or not the message data frame can be transmitted within the periodic interval, based on one round time of a frame, the transmission reference time, and the transmission time of the message data frame calculated from the data length of the reference message data frame. A network system, characterized in that: 6. A master station for monitoring a network to generate and delete a message token frame that makes a round in the network, and at least one slave station provided with a transmission opportunity of a message data frame by the message token frame. In the network, the flag area of the message token frame indicates that at least one station in the network is in a message data frame transmission waiting state, and the message transmission waiting state obtained in one round of the previous message token frame is indicated. In the master station, a frame such as a control code or a message data frame is transmitted / received to / from the network, and a transmission completion flag indicating transmission completion of transmission data, reception data, and a message data frame is indicated by the master station. Obtains the data of the message data transmission waiting flag of the message token frame and stores a message transmission waiting priority flag indicating that there is a station waiting for transmission of the message data frame on the network, and is connected to the network. The other station manages a message token frame for enabling transmission of a message data frame and controls each of the units. The slave station transmits and receives frames such as a control code and a message data frame to and from the network. And storing a transmission completion flag indicating transmission completion of transmission data, reception data, and a message data frame, and controlling each of the units. When the message token frame is received, the message in the received message token frame is stored. Message transmission priority flag data and the data of the transmission completion flag in the own station to determine whether there is a right to transmit the message data stored as the transmission data in the own station. Data communication method in a network. 7. A master station for monitoring a network and generating and erasing a message token frame that goes around the network, and at least one slave station provided with a transmission opportunity of a message data frame by the message token frame. In the network, in the master station, in the network, 1
It manages a special message token frame transmitted to measure the cycle time, sequentially transmits specific frames in accordance with a transmission cycle period set at a constant period in the network, and transmits a 1-byte reference message data frame addressed to its own station. Is transmitted and received after one round, the one round time is measured, and the one round time is transmitted as a transmission reference time to another slave station in a broadcast frame together with the transmission reference time and the one round time of the reference message token frame. The transmission time and reception time of the specific frame and the reference message data frame, the transmission reference time, and the transmission cycle interval of the specific frame are stored and the respective units are controlled. The transmission cycle period of the specific frame is obtained from the reception interval of the frame, and the master station The transmission reference time received from the storage unit stores the reception time of the specific frame and the periodic interval of the specific frame, controls the units, and receives a normal message token frame.
Based on the contents stored in each station, the time of the difference between the reception time of the specific frame and the time at which the message token frame was received, one round time of the reference message token frame, the transmission reference time, and the reference message A data communication method in a network, comprising: determining whether the message data frame can be transmitted within the periodic interval based on a transmission time of the message data frame calculated from a data length of the data frame. 8. A master station that monitors a network and generates and deletes a message token frame that goes around the network, and at least one slave station that is given a message data frame transmission opportunity by the message token frame. The first information indicating whether at least one station in the network is in a message data frame transmission waiting state, and the first information obtained in one round of the previous message token frame. And the second information indicating whether or not a station having a right to transmit the message data frame preferentially in the network is added to the message token frame, and the station that has received the message token frame Now, the received message token Based on the second information in the frame and the third information indicating whether transmission of the message data frame has been completed in the own station, it is determined whether the own station has a right to transmit the message data. A network system, characterized in that: