CN110311847B - Batch data transmission method and device - Google Patents

Abstract

The present application discloses a batch data transmission method and device. The batch data transmission method includes generating n Modbus request messages and sending the n Modbus request messages in batches according to a preset sequence, where n is greater than or equal to 1 An integer of ; within the preset timeout interval, receive m returned Modbus response messages, and determine whether the batch transmission is successful according to the received Modbus response messages, where m is an integer between 0 and n. In this application, by sending multiple Modbus request messages in batches and receiving multiple returned Modbus response messages within a preset timeout interval, the data transmission time is greatly shortened, and the delay to the slave station for time calibration is greatly reduced. errors caused.

Description

A batch data transmission method and device

technical field

The present application relates to, but is not limited to, the field of communication technologies, and in particular, relates to a method and apparatus for batch data transmission.

Background technique

Modbus protocol is a widely used response communication protocol in the field of industrial automation, and has become a general industrial standard. A feature of the answering communication protocol is that it is first-ask, first-served, and answer-in-sequence. Modbus protocol is divided into Modbus RTU (Remote Terminal Unit, RTU, Remote Terminal Unit) protocol based on serial port (RS-232, RS-422, RS-485) and Transmission Control Protocol/Internet Protocol (Transmission Control Protocol/Internet Protocol) , TCP/IP) Modbus TCP protocol. As shown in Figure 1, Modbus communication uses the master (Master, also known as the master station)-slave (Slave, also known as the slave station, equipment) technology, the master station initializes the transmission (Query, also known as query/request, and the query in turn is called the wheel query), the slave station responds accordingly according to the data provided by the master station query. The master station can communicate with the slave stations individually, and can also communicate with all the slave stations in a broadcast manner. If it communicates alone, the slave station returns a message as a response. If it is queried by broadcast, the slave station does not respond.

In the Modbus protocol, only the master station has the right to initiate a Query, and the slave station has the right to send a Response message to the master station only after receiving the Query. In other words, in the Modbus protocol, the master station can only obtain the data of the slave station through Query/Response, and the slave station can never actively send any message to the master station. As shown in Figure 2, the master station sends a request to the slave station at a certain time. After the slave station receives the request, it identifies the request and sends a response message to the master station as a receipt to the master station. The master station receives the response After the message is sent, the request session is successfully completed. In Figure 2, we record the time of a request/response as Ts, that is, the timing starts from the time the master station sends a request, the slave station receives the request and processes it internally, and then the slave station sends a response message to the master station. The interval time corresponding to the end of timing when the station receives the response from the slave station. Obviously, Ts consists of three parts, one is the time interval from when the master sends a request to when the slave receives the request, which we denote as Ta; the other is the time consumed by the slave to process the request internally, We denote it as Tb; in the third time, the slave station sends a response message to the master station, and the time interval for the master station to receive the response from the slave station, we denote it as Tc. That is, Ts=Ta+Tb+Tc.

As shown in Figure 3, the master station sequentially reads a request from the polling table as the request to be sent this time, and then generates a sending message according to the request, and starts the timeout timer after successfully sending the message (assuming the timeout time is TimeOut ). If the master station successfully receives the response message from the device within the TimeOut time, the master station will process the response message, and then the master station will enter the next sending standby state; if the master station fails to successfully receive the response message within the TimeOut time If the device responds with a response message, it is considered that the request failed, and the master station enters timeout processing (record one transmission failure, and the link needs to be reconnected if it fails continuously), and then the master station will enter the next sending standby state, and so on. .

Modbus protocol, as a typical request/response communication protocol, the conventional process is always one question and one answer, that is, the last request either timed out or got an answer before entering the next sending request. In the practical application of the Modbus protocol, it is sometimes encountered that a certain operation requires n requests/responses to be completed. school hours operation. These remote control operations and time adjustment are of course also completed by the request/response combination. Therefore, under the conventional process, such remote control and time adjustment are also completed through a serial synchronous operation of one question and one answer.

Under the conventional method, the above-mentioned remote control and time-checking operations strictly follow the conventional process of the Modbus protocol, the process is cumbersome and the operation time is lengthy, especially for the time-checking operation, the longer the operation time, the greater the time-checking error.

SUMMARY OF THE INVENTION

The present application provides a batch data transmission method and apparatus, which can greatly shorten the data transmission time.

The embodiment of the present invention provides a batch data transmission method, including:

generating n Modbus request messages, and sending the n Modbus request messages in batches in a preset order, where n is an integer greater than or equal to 1;

Within the preset timeout interval, receive m returned Modbus response messages, and determine whether the batch transmission is successful according to the received Modbus response messages, where m is an integer between 0 and n.

In an exemplary embodiment, when the n Modbus request messages are sent in batches in a preset order, the method further includes:

An exclusive identifier is set, and the exclusive identifier is used to prohibit the sending of other messages except the n Modbus request messages in the process of sending the n Modbus request messages in batches.

In an exemplary embodiment, the time for sending the n Modbus request messages is TAb, and the time for completing n batches of sending and receiving is TBb,

TAb=(n-1)*(Ta+T0)+Ta,

TBb=(n-1)*(Ta+T0)+Ts,

Among them: * is the multiplication number, Ta is the time interval from the time the master station sends a request message to the slave station receives the request message;

T0 sends the interval time to the master station;

Ts=Ta+Tb+Tc;

Tb is the time consumption for the internal processing of the request message by the slave station;

Tc is the time interval from when the slave station sends a response message to the master station until the master station receives the response message from the slave station.

In an exemplary embodiment, when the first n-1 request packets are sent sequentially, the timeout TimeOut timer is not started, and the TimeOut timer is started only after the nth request packet is sent.

In an exemplary embodiment, after the step of generating n Modbus request messages and before the step of sending the n Modbus request messages in batches in a preset order, the method further includes:

Configure one or more of the n Modbus request messages as key request messages;

The determining whether the batch transmission is successful according to the received Modbus response message includes:

If the Modbus response message corresponding to all key request messages one-to-one is received within the preset timeout interval, it is determined that this batch transmission is successful;

If the Modbus response message corresponding to all the key request messages is not received within the preset timeout time interval, it is determined that this batch transmission fails.

In an exemplary embodiment, the Modbus request message includes a Modbus TCP message or a Modbus RTU message; the Modbus response message includes a Modbus TCP message or a Modbus RTU message.

In an exemplary embodiment, when the Modbus request message and the Modbus response message are Modbus TCP messages, each time a request message is successfully sent, the request message is saved to the local first sending request message The list AQS contains the valid information of n request messages, and also includes the RF and KQ flags of each request message, where the RF flag is used to indicate whether a response message corresponding to the request message is received message, the KQ flag is used to indicate whether the request message is a key request message.

In an exemplary embodiment, when the Modbus request message and the Modbus response message are Modbus RTU messages, the generated n request messages are stored in the local second sending request list TM before being sent, Or, after the batch transmission is successful, these request messages are stored in the TM in turn; the valid information of n request messages is included in the TM, and the RF and KQ flags of each request message are also included. In order to indicate whether a response message corresponding to the request message is received, the KQ flag is used to indicate whether the request message is a key request message.

An embodiment of the present invention further provides a batch data transmission device, including a processor and a memory, wherein: the processor is configured to execute a program stored in the memory, so as to implement the steps of the method for batch data transmission as described in any of the above .

The embodiment of the present invention also provides a batch data transmission device, including a batch sending module and a batch receiving module, wherein:

a batch sending module, configured to generate n Modbus request messages, and send the n Modbus request messages in batches according to a preset sequence, where n is an integer greater than or equal to 1;

The batch receiving module is used to receive m Modbus response messages returned within a preset timeout interval, and determine whether the batch transmission is successful according to the received Modbus response messages, where m is between 0 and n the integer.

Compared with the related art, the batch data transmission method and device of the present application greatly shorten data transmission by sending multiple Modbus request messages in batches and receiving multiple returned Modbus response messages within a preset timeout interval. time, which greatly reduces the error caused by the delay to the slave station calibration.

Other features and advantages of the present application will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present application. Other advantages of the present application may be realized and attained by the means described in the specification, claims and drawings.

Description of drawings

The accompanying drawings are used to provide an understanding of the technical solutions of the present application, and constitute a part of the specification. They are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

1 is a schematic diagram of a Modbus master-slave communication network in the related art;

Fig. 2 is a kind of Modbus protocol master-slave communication conventional sequence diagram in the related art;

3 is a schematic flowchart of a Modbus data transmission method in the related art;

Fig. 4 is a kind of Modbus six-step remote control flow schematic diagram in the related art;

Fig. 5 is a kind of Modbus six-step timing calibration flow schematic diagram in the related art;

6 is a schematic flowchart of a batch data transmission method according to an embodiment of the present invention;

7 is a schematic flowchart of another batch data transmission method according to an embodiment of the present invention;

8 is a schematic diagram of a Modbus master-slave communication network according to an embodiment of the present invention;

9 is a schematic diagram of a batch remote control process according to an embodiment of the present invention;

FIG. 10 is a schematic flow chart of a batch timing correction according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a batch data transmission apparatus according to an embodiment of the present invention.

Detailed ways

Various embodiments have been described herein, but the description is exemplary rather than restrictive, and it will be apparent to those of ordinary skill in the art that within the scope of the embodiments described herein, There are many more examples and implementations. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are possible. Unless expressly limited, any feature or element of any embodiment may be used in combination with, or may be substituted for, any other feature or element of any other embodiment.

This application includes and contemplates combinations with features and elements known to those of ordinary skill in the art. The embodiments, features and elements that have been disclosed in this application can also be combined with any conventional features or elements to form unique inventive solutions as defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other inventive arrangements to form another unique inventive arrangement defined by the claims. Accordingly, it should be understood that any of the features shown and/or discussed in this application may be implemented alone or in any suitable combination. Accordingly, the embodiments are not to be limited except in accordance with the appended claims and their equivalents. Furthermore, various modifications and changes may be made within the scope of the appended claims.

Furthermore, in describing representative embodiments, the specification may have presented methods and/or processes as a particular sequence of steps. However, to the extent that the method or process does not depend on the specific order of steps described herein, the method or process should not be limited to the specific order of steps described. Other sequences of steps are possible, as will be understood by those of ordinary skill in the art. Therefore, the specific order of steps set forth in the specification should not be construed as limitations on the claims. Furthermore, the claims directed to the method and/or process should not be limited to performing their steps in the order written, as those skilled in the art will readily appreciate that these orders may be varied and still remain within the spirit and scope of the embodiments of the present application Inside.

Modbus RTU protocol is a widely used response communication protocol in the field of industrial automation, and has become the field bus (Fieldbus) industry standard. The latest industrial network market report released by Sweden's HMS Industrial Network Co., Ltd. shows that the Modbus RTU protocol ranks second in the global fieldbus market.

The Modbus RTU protocol can communicate based on various serial port standards (hereinafter referred to as serial ports) of RS-232, RS-422, two-wire RS-485 and four-wire RS-485, of which the two-wire RS-485 adopts half-duplex Working mode, that is, only one point is in the sending state at any time, other serial port standards are full-duplex working mode, that is, the data receiving and sending of these serial ports are separated, and can support data receiving and sending at the same time. Therefore, the application layer communication protocol based on the full-duplex serial port provides the possibility of batch sending and receiving at the application layer.

The batch data transmission scheme based on the Modbus RTU protocol of the present application works in a full-duplex serial port working mode.

The Modbus TCP message is to embed the Protocol Data Unit (PDU), which has nothing to do with the basic communication layer, into the application layer of the Open System Interconnection (OSI) model, and add a 6-byte header before it. The frame is formed by removing the checksum part at the end of the Modbus RTU protocol (because the TCP protocol itself contains a cyclic redundancy check CRC32 checksum). The request/response mechanism of TCP works well with the master/slave mechanism of Modbus itself.

Modbus TCP message format consists of:

header function code data

Header description:

The fields are described as follows:

1) Transaction ID, used for transaction pairing. The Modbus server copies the transaction ID from the client request when responding.

Requests and responses correspond to transaction IDs. Therefore, at the same time, the transaction ID of the TCP connection must be unique. The standards committee recommends that the transaction identification may be a simple count - the message sequence number (referred to as the sequence number), which is incremented by 1 each time the master requests it. It has been more than ten years since the Modbus TCP protocol appeared, and mainstream manufacturers will adopt the standard recommendation, that is, the transaction identifier is actually the sequence number.

2) Protocol identification, which is used for multiple identification in the system. Modbus protocol is identified with '0'.

3) The length field is counted in bytes, including the unit identification and data fields.

4) Unit identification, used for routing within the system. Its typical application is that the return value of the request and the server response message must be the same in this field.

In some cases, the unit ID carries the Modbus slave address of the remote device. But at the TCP layer, the Modbus server is addressed with its IP address, so the Modbus unit identification is meaningless. At this time, the value of this field is 0xFF.

But if the slave has its own subnet, the device address can also be from 1 to 247.

Application of serial number:

I) For each message, the master station will initialize the slave station and generate a sequence number;

II) The response information of the slave station shall use the same sequence number sent from the master station;

III) The master should confirm that the sequence number received from the slave is the same as the sequence number previously sent to the slave;

The principle for the master station to increase the sequence number value:

A) The sequence number is stored in two bytes;

B) The range of sequence number should be (0-65535) or (0x0000to 0xFFFF);

C) The starting value of the sequence number should be 0;

D) For each message sent by the master station, including for normal polling, fault polling, retry information or control, the master station should increase the sequence number value by 1;

E) If the master station finds that the sequence number of the response information of the slave station is wrong, it should ignore the information and announce that the communication state is not good.

In summary, the Modbus TCP protocol has the following key features:

(1) The first two bytes of the Modbus TCP protocol message are called "transaction identifier", which is actually the sequence number.

(2) The master station determines the value of the sequence number, and the slave station must copy the sequence number in the request as a response.

(3) Each time the master station sends a request, the sequence number will be incremented by one.

Assume the application scenarios of the following two Modbus protocols (Modbus RTU protocol or Modbus TCP protocol):

Application scenario 1 under the conventional method: As shown in Figure 4, the remote control of a slave device needs to be divided into 6 steps, namely: remote control enable, remote control execution, remote control enable cancellation, remote control enable, remote control execution reset, The remote control enable is canceled. Under normal circumstances, the complete process of the remote control needs to be divided into six rounds of response, which are: 1) The master station sends the remote control enable, and the slave station responds to the remote control enable; 2) After the master station receives the remote control enable response, it sends the remote control execution, and the slave The station responds to the remote control execution; 3) After the master station receives the remote control execution response, it sends the remote control enable cancellation, and the slave station responds to the remote control enable cancellation; 4) After the master station receives the remote control enable cancellation, it sends the remote control enable, and the slave station responds Remote control enable; 5) After the master station receives the remote control enable response, it sends the remote control execution clearing, and the slave station responds to the remote control execution clearing; 6) After the master station receives the remote control execution clearing response, it sends the remote control enable cancellation, and the slave station The station responds to the remote control enable cancellation, and the master station completes the current round of remote control operations after receiving the remote control enable cancellation.

Application scenario 2 under the conventional method: As shown in Figure 5, the time adjustment of a slave device needs to be divided into 6 steps. The master station sends a message with function code 6 in turn, and the message carries the year, Month, day, hour, minute, second.

When using the Modbus RTU protocol for serial communication, Ta and Tc are related to the number of message bytes and the baud rate of serial communication (hereinafter referred to as the baud rate), which are proportional to the number of message bytes and the baud rate. Inversely proportional, at a classic 9600bps baud rate, it takes about 1 millisecond to transmit a byte. Tb is related to the slave device, depending on the hardware performance of the device and its software processing capability. Generally, Tb is between 5 and 20 milliseconds.

For the sake of illustration, we might as well take the baud rate of 9600bps, and the time-consuming to transmit one byte is about 1 millisecond. The message length of a typical Modbus RTU request (function code 1, 2, 3, 4, 5, 6) is 8 bytes, at this time, Ta=8 milliseconds; the response message of function code 1, 2, 3, 4 The length of the message depends on the corresponding number of points in the request. The value ranges from 6 to 256 bytes, so Tc=6 to 256 milliseconds; the corresponding message of function codes 5 and 6 is also 8 bytes, and at this time, Tc=8 milliseconds.

In Modbus communication, after the master station receives the response from the slave station of the previous request, it usually needs to have a certain active rest time before sending the next request, referred to as the master station delay time, or the master station interval time (denoted as T0) , there are two purposes: one is to control the communication flow between the master and slave communication parties, and the other is if T0 is 0 (meaning that the master station immediately sends the next request after receiving the response from the slave station of the previous request), some The slave station is often unable to handle it, which may cause abnormal communication or even interruption. The value range of T0 is usually 0 to 100 milliseconds.

We record the time to complete n batches of sending as TA, and the time to complete n batches of sending and receiving as TB.

In order to facilitate the distinction, we specially note that when using the traditional Modbus protocol for communication, TA is TAa and TB is TBa; when using the batch data transmission scheme of this application for communication, TA is TAb and TB is TBb.

As shown in Figure 2, under the conventional method, the next transmission must wait for the completion of the previous transmission/reception. The transmission time of the nth time is Ta, and the transmission/reception time of the nth time is Ts. Ts=Ta+Tb+Tc, therefore,

TAa=(n-1)*(Ts+T0)+Ta-------(1)

TBa=(n-1)*(Ts+T0)+Ts-------(2)

Embodiment 1 Batch data transmission method

As shown in FIG. 6 , an embodiment of the present invention provides a batch data transmission method, including the following steps:

Step 601: Generate n Modbus request messages, and send the n Modbus request messages in batches according to a preset sequence, where n is an integer greater than or equal to 1;

In an exemplary embodiment, the Modbus request message includes a Modbus RTU message or a Modbus TCP message.

In an exemplary embodiment, when the n Modbus request messages are sent in batches in a preset order, the method further includes:

An exclusive identifier is set, and the exclusive identifier is used to prohibit the sending of other messages except the n Modbus request messages in the process of sending the n Modbus request messages in batches.

In this embodiment, when sending n Modbus request messages in batches, set the exclusive flag (Lock for short) to true, and set Lock to false after the batch request is sent, to ensure that the master station sends n Modbus request messages in batches During this time, no other requests are inserted. Why would it be possible to insert other requests? Because the sending and receiving of the master station are often two independent threads, it is possible to receive the response from the slave station after n batch requests are sent to the x (x<n) request, which will trigger the master station. If there is no Lock flag, the master station may trigger a new round of requests, resulting in the insertion of unexpected requests after the xth request. With the Lock flag, even if the master station receives a response from the slave station during batch transmission, after the master station receives and processes normally, and then checks that the Lock flag is true, the master station will not generate a new request, thus preventing the master station from batching. During the sending of the request, insert any other requests.

After the batch transmission scheme of the present application is adopted, the next transmission only needs to wait for the completion of the previous transmission. is Ta, that is, TAb=(n-1)*(Ta+T0)+Ta. Next, let's calculate TBb. We only need to calculate the time when the master station receives its response after the nth request is sent (recorded as TimeN) to calculate TBb, because one of the characteristics of the response communication protocol is First ask, first serve, and answer in sequence, so as long as the master station receives the response of the nth request, it means that the master station must have received all the responses of the previous (n-1) requests before that. According to the agreement, the sending/receiving time of any request is Ts=Ta+Tb+Tc. Therefore, in this application, the n-th sending/receiving time is also Ts. therefore:

TAb=(n-1)*(Ta+T0)+Ta;

TBb=(n-1)*(Ta+T0)+Ts.

In an exemplary embodiment, after the step of sending the n Modbus request messages in batches in a preset order, the method further includes:

Store the sent Modbus request message in the send request queue.

In an exemplary embodiment, after the step of generating n Modbus request messages and before the step of sending the n Modbus request messages in batches in a preset order, the method further includes:

Configure one or more of the n Modbus request messages as key request messages.

In an exemplary embodiment, a preset sending interval is set between every two sent Modbus request packets, so as to facilitate the slave station to identify different requests and enable the slave station to process them.

In an exemplary embodiment, the master station does not start the timeout TimeOut timer when sending the first n-1 request messages in sequence, and starts the TimeOut timer only after sending the nth request message.

Step 602: Receive m returned Modbus response messages within a preset timeout interval, and determine whether the batch transmission is successful according to the received Modbus response messages, where m is an integer between 0 and n.

It should be noted that, because the Modbus TCP protocol and the Modbus RTU protocol have the following differences:

1. Physically, the Ethernet TCP protocol is full-duplex, and the communication nodes on the Ethernet can receive and send at the same time;

2. As the application layer protocol of TCP, the Modbus TCP protocol message contains the "packet sequence number" field (ie sequence number), and both the master and the slave can use the "packet sequence number" to clearly identify the Modbus TCP in the received data stream. message;

Therefore, when parsing the received Modbus TCP response message, it can be parsed according to the packet sequence number field in the Modbus TCP response message and the specific content of the message; when parsing the received Modbus RTU response message, it can be Analyze according to the specific content of the Modbus RTU response message.

In an exemplary embodiment, after the step of receiving the returned m Modbus response messages, the method further includes:

Determine the Modbus request message corresponding to each Modbus response message, and modify the reception flag RF (Response Flag, 0 is the initial state of the corresponding Modbus request message in the sending request queue, 1 indicates that the request has successfully received the device response, RF1, RF2, ..., RFn represent the reception flags of requests 1, 2, ... n respectively).

In an exemplary embodiment, determining whether the batch transmission is successful this time according to the received Modbus response message includes:

If a Modbus response message corresponding to all sent Modbus request messages is received within the preset timeout interval, it is determined that the batch transmission is successful;

If no Modbus response message corresponding to all sent Modbus request messages is received within the preset timeout interval, it is determined that the batch sending fails.

In another exemplary embodiment, the determining whether the batch transmission is successful this time according to the received Modbus response message includes:

If a Modbus response message corresponding to all key request messages is received within the preset timeout interval, it is determined that the batch transmission is successful;

If no Modbus response message corresponding to all key request messages is received within the preset timeout interval, it is determined that this batch transmission fails.

In an exemplary embodiment, the method further includes:

If it is determined that this batch transmission is successful, delete the Modbus request message and its flag sent in the transmission request queue;

If it is determined that this batch transmission fails, check whether it needs to be retransmitted; if retransmission is required, retransmit the n Modbus request messages in batches according to the preset order; Modbus request message and its flags.

In an exemplary embodiment, we assume that an operation needs to include n requests/responses to complete, and the corresponding n requests and responses are respectively recorded as: Q1/R1, Q2/R2, ..., Qn/ Rn.

As shown in Figure 7, the master station first checks whether batch sending requests are currently required, and if not, it enters the master-slave conventional communication process; if necessary, it enters the batch sending request process.

Exemplarily, in the batch sending request process, if the Modbus TCP protocol is used, firstly generate n requests Q1, Q2, . , Qn, every time a request is successfully sent, the request is saved to the local first sending request list (Array of Querys Sent, AQS for short), and AQS also includes RF (Response Flag, the initial value is 0) and KQ (Key Query, 1 indicates whether the request is a critical request, the default value is 1, the KQ of all requests is 1, indicating that all requests need to be returned to school), and the "package number" is used as the subscript index of AQS (we record the n requests and The "packet sequence numbers" corresponding to the responses are SN1, SN2, ..., SNn). Note that in these n requests, there is usually a certain sending interval (denoted as T0) between two requests, because it is convenient for the slave to identify different requests and enable the slave to process it. T0 defaults to 5 milliseconds and Adjustable configuration, the minimum available value of T0 often depends on the slave device, generally T0 is given directly by the slave side or given according to actual tests. It is specially stated that T0 is a device attribute parameter, which is by no means a special parameter specifically required or relied on by this patent, and will not be further elaborated here. After the master station successfully sends all n requests Q1, Q2, ..., Qn in sequence, it starts the timeout timer with the timeout time TimeOut (TimeOut is generally 1000 milliseconds, configurable). After the device receives the request sequence, it will respond to R1, R2, ..., Rn in turn. The master station parses out R1 in turn from the received data stream according to the sending information in AQS, especially the "packet sequence number" in the sending information. R2,...,Rn, and juxtapose the corresponding return value RF to 1 to indicate that the master station has successfully received R1, R2,..., Rn. After each receiving process, the master station checks the RF value of all requests with KQ of 1 in AQS. If the master station has the RF value of all requests with KQ of 1 to 1 within the TimeOut time, it means that all requests have been successfully received. The response of the key request, because the KQ of all requests is usually 1 (configurable), it usually means that all the responses of R1, R2, ..., Rn are received. At this time, the TimeOut timer is aborted and this The second batch of requests to send the transaction is successful and enter the next round of sending transactions; if the TimeOut timeout timer arrives, as long as the RF of any request whose KQ is 1 in the AQS is not 1, it means that the response to all key requests has not been successfully received. , it declares that the batch request failed to be sent. If it needs to be retransmitted, it will enter the retransmission process. If it does not retransmit, clear the AQS and its flag, and then enter the next round of sending transactions.

Exemplarily, in the batch sending request process, if the Modbus RTU protocol is used, the master station generates n sequential sending messages (the n sequential messages are sequentially recorded as Q1, Q2,..., Qn-1, Qn) , these requests are stored in the local second sending request list (denoted as TM, TM contains Q1, Q2, ..., Qn-1, Qn valid information, each request also includes RF and KQ flags, RF and KQ meanings And the usage is the same as above) (the requests can also be stored in the local second sending request list TM after the master station sends the requests in sequence successfully). After the master station successfully sends all n requests Q1, Q2, ..., Qn in sequence, it starts the timeout timer with the timeout time TimeOut (TimeOut is generally 1000 milliseconds, configurable). After the device receives the request sequence, it will respond to R1, R2, ..., Rn in sequence, and the master station will parse out R1, R2, ..., Rn in turn from the received data stream according to the sent information in the TM, and juxtapose the corresponding The return value of RF is 1 to indicate that the master station has successfully received R1, R2, ..., Rn. The master station checks the RF value of all requests with KQ of 1 in the TM after each receiving and processing. If the master station has the RF value of all requests with KQ of 1 to 1 within the TimeOut time, it means that all requests have been successfully received. The response of the key request, because the KQ of all requests is usually 1 (configurable), it usually means that all the responses of R1, R2, ..., Rn are received. At this time, the TimeOut timer is aborted and this The second batch of requests to send the transaction is successful, and the next round of sending transactions is entered; if the TimeOut timeout timer arrives, as long as the RF of any request whose KQ is 1 in the TM is not 1, it means that the response to all key requests has not been successfully received. , it declares that the batch request failed to be sent. If it needs to be retransmitted, it will enter the retransmission process. If it does not retransmit, clear the TM and its flag, and enter a new round of response process. Obviously, when n=1, this application is completely consistent with the conventional one-question-one-answer method.

As shown in Figure 8, the master station continuously sends four requests in batches according to the batch transmission scheme of the present application. The slave station identifies the four requests in sequence and replies to the master station with corresponding four response messages. Visually represents the asynchronous concurrent processing effect when the application executes batch requests. Asynchronous means that the next request can be sent without waiting for a response after a request; concurrency means that in a continuous period of time, the master station continues to send multiple requests without the device responding.

Embodiment 2 Batch data transmission device

An embodiment of the present invention further provides a batch data transmission apparatus, including a processor and a memory, wherein: the processor is configured to execute a program stored in the memory, so as to implement the steps of the method for batch data transmission as described in any of the above .

Embodiment 3 Batch data transmission device

As shown in FIG. 11, an embodiment of the present invention further provides a batch data transmission device, including a batch sending module 1101 and a batch receiving module 1102, wherein:

The batch sending module 1101 is configured to generate n Modbus request messages, and send the n Modbus request messages in batches according to a preset order, wherein n is an integer greater than or equal to 1;

The batch receiving module 1102 is used to receive m Modbus response messages returned within a preset timeout interval, and determine whether the batch transmission is successful according to the received Modbus response messages, where m is between 0 and n. integer between.

In an exemplary embodiment, the Modbus request message includes a Modbus RTU message or a Modbus TCP message; the Modbus response message includes a Modbus RTU message or a Modbus TCP message.

In an exemplary embodiment, when the Modbus request message and the Modbus response message are ModbusTCP messages, each time the batch sending module 1101 successfully sends a request message, it saves the request message locally. The first sending request list AQS contains the valid information of n request messages, and also includes the RF and KQ flags of each request message, wherein the RF flag is used to indicate whether the request message is received or not. In the corresponding response message, the KQ flag is used to indicate whether the request message is a key request message.

In an exemplary embodiment, when the Modbus request message and the Modbus response message are Modbus RTU messages, the batch sending module 1101 stores the generated n request messages in the local second sending message before sending. The request list TM, or, after the master station successfully sends the request messages in batches, store these request messages in the TM in turn; the TM contains the valid information of n request messages, and also includes the RF and KQ flags of each request message , where the RF flag is used to indicate whether a response message corresponding to the request message is received, and the KQ flag is used to indicate whether the request message is a key request message.

In an exemplary embodiment, the batch sending module 1101 is further configured to:

When sending the n Modbus request messages in batches according to the preset order, an exclusive flag is set, and the exclusive flag is used to prohibit the removal of the n Modbus request messages during the process of sending the n Modbus request messages in batches The sending of other messages other than the message.

In an exemplary embodiment, assuming that the time when the batch sending module 1101 sends the n Modbus request messages is TAb, and the time when the batch receiving module 1102 completes n batches of sending and receiving messages is TBb, then:

TAb=(n-1)*(Ta+T0)+Ta,

TBb=(n-1)*(Ta+T0)+Ts,

Among them: * is the multiplication number, Ta is the time interval from the time the master station sends a request message to the slave station receives the request message;

T0 sends the interval time to the master station;

Ts=Ta+Tb+Tc;

Tb is the time consumption for the internal processing of the request message by the slave station;

Tc is the time interval from when the slave station sends a response message to the master station until the master station receives the response message from the slave station.

In an exemplary embodiment, the batch sending module 1101 does not start the timeout TimeOut timer when sending the first n-1 request messages in sequence, and starts the TimeOut timer only after sending the nth request message.

In an exemplary embodiment, the batch sending module 1101 is further configured to:

After the n Modbus request messages are sent in batches according to the preset sequence, the sent Modbus request messages are stored in the sending request queue.

In an exemplary embodiment, the batch sending module 1101 is further configured to configure one or more of the n Modbus request messages as key request messages.

In an exemplary embodiment, a preset sending interval is set between each two Modbus request packets sent by the batch sending module 1101, so as to facilitate the slave station to identify different requests and enable the slave station to process them .

In an exemplary embodiment, the batch receiving module 1102 is further configured to:

Determine the Modbus request message corresponding to each Modbus response message, and modify the reception flag of the corresponding Modbus request message in the sending request queue.

In an exemplary embodiment, the batch receiving module 1102 determines whether the batch sending is successful according to the received Modbus response message, including:

If a Modbus response message corresponding to all sent Modbus request messages is received within the preset timeout interval, it is determined that the batch transmission is successful;

If no Modbus response message corresponding to all sent Modbus request messages is received within the preset timeout interval, it is determined that this batch transmission fails.

In another exemplary embodiment, determining whether the batch sending this time is successful according to the received Modbus response message by the batch receiving module 1102 includes:

If a Modbus response message corresponding to all key request messages is received within the preset timeout interval, it is determined that the batch transmission is successful;

If no Modbus response message corresponding to all key request messages is received within the preset timeout interval, it is determined that this batch transmission fails.

In an exemplary embodiment, the batch receiving module 1102 is further configured to:

If it is determined that this batch transmission is successful, delete the Modbus request message sent in the sending request queue;

If it is determined that this batch transmission fails, check whether retransmission is required; if retransmission is required, retransmit the n Modbus request messages in batches according to the preset order; if retransmission is not required, delete the description in the transmission request queue Modbus request message sent.

After the batch transmission scheme of the present application is adopted, the next transmission only needs to wait for the completion of the previous transmission. is Ta, that is, TAb=(n-1)*(Ta+T0)+Ta. Next, let's calculate TBb. We only need to calculate the time when the master station receives its response after the nth request is sent (recorded as TimeN) to calculate TBb, because one of the characteristics of the response communication protocol is First ask, first serve, and answer in sequence, so as long as the master station receives the response of the nth request, it means that the master station must have received all the responses of the previous (n-1) requests before that. According to the agreement, the sending/receiving time of any request is Ts=Ta+Tb+Tc. Therefore, in this application, the n-th sending/receiving time is also Ts. therefore:

TAb=(n-1)*(Ta+T0)+Ta-------(3)

TBb=(n-1)*(Ta+T0)+Ts-------(4)

In particular, in the following representations and calculations, we hide the unit, and note that the time unit is milliseconds.

In order to facilitate the distinction, we specially note that when using traditional serial communication, TA is TAa1 and TB is TBa1; when using traditional Modbus TCP protocol communication, TA is TAa2 and TB is TBa2.

In serial communication mode, generally:

Ta=8, Tb ∈ [5, 20], Tc ∈ [6, 256], T0 ∈ [0, 100].

We take the minimum value of the above four parameters, namely: Ta=8, Tb=5, Tc=6, T0=0, we can get Ts=19, and substitute it into formulas (1) to (4), we can get:

TAa 1=19n-11-------(5)

TBa 1 = 19n------------(6)

TAb1=8n------------(7)

TBb1=8n+11-------(8)

When n=1, obviously, TAa1=TAb1=8=Ta; TBa1=TBb1=19=Ts.

When n=6, TAa1=103, TBa1=114; TAb1=48, TBb1=59.

We take the maximum value of the above four parameters, namely: Ta=8, Tb=20, Tc=256, T0=100, we can get Ts=284, and substitute it into formulas (1) to (4), we can get:

TAa1=292n-284-------(9)

TBa 1=292n-8---------(10)

TAb1=108n-100------(11)

TBb1=108n+176------(12)

When n=1, obviously, TAa1=TAb1=8=Ta; TBa1=TBb1=284=Ts.

When n=6, TAa1=1468, TBa1=1744, TAb1=548, TBb1=824.

We take the above four parameters as typical representative values, namely: Ta=8, Tb=10, Tc=8, T0=5, we can get Ts=26, and substituting into formulas (1) to (4), we can get:

TAa1=31n-23-------(13)

TBa1=31n-5-------(14)

TAb1=13n-5-------(15)

TBb1=13n+13------(16)

When n=1, obviously, TAa1=TAb1=8=Ta; TBa1=TBb1=26=Ts.

When n=6, TAa1=163, TBa1=181, TAb1=73, TBb1=91.

When the batch transmission scheme of the present application is applied to the above application scenario 1: remote control scenario, as shown in Figure 9, the master station continuously sends six requests in batches, and the slave stations identify the six requests in sequence and reply to the master station in turn The corresponding six response packets. In a typical scenario (Ta=8, Tb=10, Tc=8, T0=5), when using the conventional one-to-one sending method, it takes 163 milliseconds to send a round of all remote control transactions (TAa); When the transmission scheme is used, it only takes 73 milliseconds, which is equivalent to 45% of the normal transmission time; when using the conventional one-to-one transmission method, it takes 181 milliseconds to complete a round of all remote transactions (TAb); when using the batch transmission scheme of this application , it only takes 91 milliseconds, which is equivalent to 50% of the normal completion time;

When the batch transmission scheme of the present application is applied to the above application scenario 2: time school scenario, as shown in Figure 10, the master station continuously sends six requests in batches, and the slave stations identify the six requests in sequence and send them to the master station in turn. Reply to the corresponding six response packets. In this scenario, we should pay more attention to the time when the device receives all commands. Obviously, this value is equal to TA. In a typical scenario (Ta=8, Tb=10, Tc=8, T0=5), when using the conventional one-to-one sending method, it takes 163 milliseconds to send a round of all remote control transactions (TAa); When the transmission scheme is used, it only takes 73 milliseconds, which is equivalent to 45% of the normal transmission time; when using the conventional one-to-one transmission method, it takes 181 milliseconds to complete a round of all remote transactions (TAb); when using the batch transmission scheme of this application , it only takes 91 milliseconds, which is equivalent to 50% of the normal completion time. Further, since TAb=(n-1)*(Ta+T0)+Ta, for the master station, n is known. As mentioned above, under serial communication, Ta is only related to the transmission bytes and baud rate correlation, so T0 is also known. We can calculate the value of TAb=(n-1)*(Ta+T0)+Ta in advance, and make time compensation by the master station, the time in the message=master station time+TAb, through the time compensation of the master station, When the batch transmission scheme of the present application is used, the error caused by the delay to the time calibration of the slave station is completely avoided during the full-duplex communication of the serial port. In the conventional transmission method, TAa=(n-1)ⅹ(Ts+T0)+Ta=(n-1)*(Ta+Tb+Tc+T0)+Ta, since Tb is not constant, this is the master station The compensation brings greater difficulty and error.

In TCP/IP Ethernet communication, in the case of transmission of short messages (below 1024 bytes), Ta and Tc are often only sensitive to network delay, and have little to do with message length. Since the maximum message length of Modbus TCP is only 260 bytes, in a local area network, the value range of Ta and Tc is usually 1 to 10 milliseconds. Tb is related to the slave device, depending on the hardware performance of the device and its software processing capability. Generally, Tb is between 5 and 20 milliseconds. That is, in an industrial LAN, generally:

Ta ∈ [1, 10], Tb ∈ [5, 20], Tc ∈ [1, 10], T0 ∈ [0, 100].

We take the minimum value of the above four parameters, namely: Ta=1, Tb=5, Tc=1, T0=0, we can get Ts=7, and substitute it into formulas (1) to (4), we can get:

TAa2=7n-6-------(17)

TBa 2 = 7n---------(18)

TAb2=n-------(19)

TBb2=n+6-------(20)

When n=1, obviously, TAa2=TAb2=1=Ta; TBa2=TBb2=7=Ts.

When n=6, TAa2=36, TBa2=42; TAb2=6, TBb2=12.

We take the maximum value of the above four parameters, namely: Ta=10, Tb=20, Tc=10, T0=100, we can get Ts=40, and substitute it into formulas (1) to (4), we can get:

TAa 2=140n-130-------(21)

TBa 2 = 140n-100-------(22)

TAb 2 = 110n-100-------(23)

TBb 2=110n-70-------(24)

When n=1, obviously, TAa2=TAb2=10=Ta; TBa2=TBb2=40=Ts.

When n=6, TAa2=710, TBa2=740, TAb2=560, TBb2=590.

We take the above four parameters as typical representative values, namely: Ta=2, Tb=10, Tc=2, T0=5, we can get Ts=14, and substitute them into formulas (1) to (4), we can get:

TAa2=16n-14-------(25)

TBa2=16n-2-------(26)

TAb2=7n-5---------(27)

TBb2=7n+7---------(28)

When n=1, obviously, TAa2=TAb2=2=Ta; TBa2=TBb2=14=Ts.

When n=6, TAa2=82, TBa2=94, TAb2=37, TBb2=49.

When the batch transmission scheme of the present application is applied to the above application scenario 1: remote control scenario, in a typical scenario (Ta=2, Tb=10, Tc=2, T0=5), when using the conventional one-to-one transmission method , it takes 82 milliseconds to send one round of all remote control transactions (TAa2); when using the batch transmission scheme of the present application, it only takes 37 milliseconds, which is equivalent to 45% of the normal sending time; when using the conventional one-to-one sending method, one It takes 94 milliseconds to complete all remote transactions (TAb2); when using the batch transmission scheme of this application, it only takes 49 milliseconds, which is equivalent to 52% of the normal completion time;

When the batch transmission scheme of the present application is applied to the above application scenario 2: the time school scenario, in this scenario, we should pay more attention to the time when the device receives all commands. Obviously, this value is equal to TA. In a typical scenario (Ta=2, Tb=10, Tc=2, T0=5), when using the conventional one-to-one sending method, it takes 82 milliseconds to send one round of all remote control transactions (TAa2); When the transmission scheme is used, it only takes 37 milliseconds, which is equivalent to 45% of the normal transmission time. Further, since TAb=(n-1)(Ta+T0)+Ta, for the master station, n is known and T0 is known, leaving the only variable Ta. As mentioned above, in the local area network, Ta is It is only related to the network delay. In most cases, Ta oscillates in a narrow range around a fixed value T0'. We can calculate the value of TAb'=(n-1)*(Ta+T0')+Ta in advance, and use The master station performs time compensation, the time in the message = the master station time + TAb', through the time compensation of the master station, when using the batch transmission scheme of this application, the error caused by the delay to the slave station time calibration is greatly reduced . In the conventional one-to-one transmission method, TAa=(n-1)*(Ts+T0)+Ta=(n-1)*(Ta+Tb+Tc+T0)+Ta, which is Compensation brings greater difficulty and error.

The present application implements a method for batch sending and batch receiving of Modbus protocol, which converts the conventional one-question-one-answer synchronous serial mode into an asynchronous concurrent mode of batch continuous sending and batch continuous receiving. Asynchrony refers to a After a request, the next request can be sent without waiting for a response; concurrency means that in a continuous period of time, the master station continues to send multiple requests without a device responding.

In the multi-step remote control mode, the batch transmission scheme of the present application can greatly compress the sending time and complete execution time of the remote control;

In some time-sensitive multi-step operation modes, such as time correction operation, the batch transmission scheme of the present application can greatly reduce the error caused by the delay to the time correction of the slave station through the time compensation of the master station;

The batch transmission scheme of the present application is simple and easy to understand, does not need to rely on high-performance software and hardware, and is applicable to any software/hardware platform.

Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, functional modules/units in the systems, and devices can be implemented as software, firmware, hardware, and appropriate combinations thereof. In a hardware implementation, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be composed of several physical components Components execute cooperatively. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer-readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). As known to those of ordinary skill in the art, the term computer storage media includes both volatile and nonvolatile implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules or other data flexible, removable and non-removable media. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cartridges, magnetic tape, magnetic disk storage or other magnetic storage devices, or may Any other medium used to store desired information and which can be accessed by a computer. In addition, communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and can include any information delivery media, as is well known to those of ordinary skill in the art .

Claims (9)

1. a batch data transmission method, is characterized in that, comprises: generating n Modbus request messages, and sending the n Modbus request messages in batches in a preset order, where n is an integer greater than or equal to 1; Within the preset timeout interval, receive m returned Modbus response messages, and determine whether the batch transmission is successful according to the received Modbus response messages, where m is an integer between 0 and n; When the n Modbus request messages are sent in batches according to the preset order, the method further includes: An exclusive identifier is set, and the exclusive identifier is used to prohibit the sending of other messages except the n Modbus request messages in the process of sending the n Modbus request messages in batches; The time for sending the n Modbus request messages is TAb, TAb=(n-1)*(Ta+T0)+Ta, Among them: * is the multiplication number, Ta is the time interval from when the master station sends a request message to when the slave station receives the request message; T0 is the interval time for the master station to send it; The value of TAb is obtained by calculation, and the master station performs time compensation according to the value of TAb. The time compensation formula is as follows: Time in the message=master station time+TAb. 2. The method according to claim 1, wherein The time to complete n batches of sending and receiving is TBb, TBb=(n-1)*(Ta+T0)+Ts, Ts=Ta+Tb+Tc; Tb is the time consumption for the internal processing of the request message by the slave station; Tc is the time interval from when the slave station sends a response message to the master station until the master station receives the response message from the slave station. 3. method according to claim 2, is characterized in that, when sending the first n-1 request message sequentially, do not start time-out TimeOut timer at all, just start TimeOut timing only after sending the nth request message device. 4. The method according to claim 1, characterized in that, after the step of generating n Modbus request messages and before the step of sending the n Modbus request messages in batches in a preset order, the The method also includes: Configure one or more of the n Modbus request messages as key request messages; The determining whether the batch transmission is successful according to the received Modbus response message includes: If the Modbus response message corresponding to all key request messages one-to-one is received within the preset timeout interval, it is determined that this batch transmission is successful; If the Modbus response message corresponding to all the key request messages is not received within the preset timeout time interval, it is determined that this batch transmission fails. 5. according to the arbitrary described method of claim 1 to 4, it is characterized in that, described Modbus request message comprises ModbusTCP message or Modbus RTU message; Described Modbus response message comprises Modbus TCP message or Modbus RTU message arts. 6. The method according to claim 5, wherein: When the Modbus request message and the Modbus response message are Modbus TCP messages, each time a request message is successfully sent, the request message is saved in the local first sending request list AQS, and the AQS contains n The valid information of each request message, and also includes the RF and KQ flags of each request message, where the RF flag is used to indicate whether a response message corresponding to the request message is received, and the KQ flag is used to indicate the Whether the request message is a key request message. 7. The method according to claim 5, wherein: When the Modbus request message and the Modbus response message are Modbus RTU messages, the generated n request messages are stored in the local second sending request list TM before sending, or, after the batch sending is successful, the These request messages are stored in the TM in turn; the TM contains the valid information of n request messages, and also includes the RF and KQ flags of each request message, where the RF flag is used to indicate whether the request is received or not. The response message corresponding to the message, and the KQ flag is used to indicate whether the request message is a key request message. 8. A batch data transmission device, comprising a processor and a memory, wherein: the processor is used to execute a program stored in the memory, so as to realize the method according to any one of claims 1 to 7. The steps of the bulk data transfer method. 9. A batch data transmission device, comprising a batch sending module and a batch receiving module, wherein: The batch sending module is used to generate n Modbus request messages, and send the n Modbus request messages in batches according to a preset sequence, including setting an exclusive identifier, and the exclusive identifier is used to send the n Modbus requests in batches During the message process, the sending of other messages except the n Modbus request messages is prohibited, where n is an integer greater than or equal to 1; The time for sending the n Modbus request messages is TAb, TAb=(n-1)*(Ta+T0)+Ta, Among them: * is the multiplication number, Ta is the time interval from when the master station sends a request message to when the slave station receives the request message; T0 is the interval time for the master station to send it; The value of TAb is obtained by calculation, and the master station performs time compensation according to the value of TAb. The time compensation formula is as follows: time in the message = master station time + TAb; The batch receiving module is used to receive m Modbus response messages returned within a preset timeout interval, and determine whether the batch transmission is successful according to the received Modbus response messages, where m is between 0 and n the integer.

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