CN100493079C - Method for main node supporting different agreement type secondary unit apparatus on secondary node - Google Patents

Abstract

The invention discloses a method for a master node to support slave unit devices of different protocol types on a slave node. In the master-slave communication protocol, the message content key value and message content mask of each protocol type slave unit device are preset, and the The corresponding relationship between the message content mask of the slave unit device of the same protocol type, the key value of the message content and the upper layer application program, the method includes the following steps: After the master node receives the message sent from the slave node, it selects the unselected A message content mask of a protocol type, and obtain the message content key value by the selected message content mask; compare the obtained message content key value with the message content key value of the protocol type, if If they are the same, then select the upper-layer application program corresponding to the message content key value of the protocol type, and if not, discard the slave node message. The method of the invention realizes the support to the slave unit devices of different protocol types, and can flexibly adapt to the change and increase or decrease of the slave unit devices of different protocol types on the slave node.

Description

The master node supports the method of slave unit devices of different protocol types on the slave node

technical field

The invention relates to a communication protocol technology, in particular to a method for a master node to support slave unit devices of different protocol types on the slave node.

Background technique

A system that completes a specific function is generally composed of a plurality of subsystem units with relatively independent functions. unit. The master unit is the subsystem in the control position in the system, which completes the main functions of the system and controls other subsystems; the slave unit is the subsystem in the controlled position in the system, completes the auxiliary functions of the system, and accepts the control of the master unit.

Figure 1 is a schematic diagram of the relationship between master and slave nodes. Referring to Figure 1, a general system has a master node and one or more slave nodes. The master node and the slave nodes communicate with each other through a communication channel, and communicate through a master-slave communication protocol, and the communication channel is time-division multiplexed.

The master-slave communication protocol is the communication protocol that the master unit device and the slave unit device in the system follow when they communicate with each other. In the master-slave communication protocol, the master unit corresponds to the concept of the master node, the slave unit corresponds to the concept of the slave node, the node is a logical concept, and the unit is a physical concept, which refers to a subsystem that completes a specific function.

There are different types of slave unit devices in the system. The different types of slave unit devices do not mean that the functions of the slave unit devices are different, but that the protocol types that the slave unit devices and the master unit devices follow when exchanging messages are different, and that they are different from these protocols. Corresponding to different upper-level applications.

In the existing master-slave communication protocol, the master node identifies slave unit devices that comply with different protocol types through the slave node identifier, and then finds the upper layer application program of the slave unit device on the slave node to complete the support for the slave unit device.

The existing technology realizes that the master node supports slave unit devices of different protocol types on the slave node as follows:

Method 1: Set the corresponding relationship between the slave node number and the protocol type, and the master node identifies the slave unit devices that comply with different protocol types through the slave node number. The slave node number of the device is determined by the hardware, each device has a dial switch, and the slave node number of the device is set through the dial switch. For example, if there are slave unit device A and slave unit device B that comply with different protocol types, set the slave node number corresponding to the protocol type that device A complies with to 1, then when installing device A, dial the DIP switch of device A To the position of 1, when the slave node 1 where device A is located sends a message to the master node, the master node identifies device A through the slave node number 1 in the message, and finds the upper layer application program of device A, and completes the device A support.

If the DIP switch of device A is not dialed to the 1 position, that is, there is no corresponding relationship between the slave node number of device A and the protocol type 1 that device A complies with, then device A will not be supported; if the device that complies with protocol type 2 The DIP switch of B is turned to the 1 position, because there is no corresponding relationship between the protocol type 2 complied with by the device B and the slave node number 1, then the device B will not be supported. It can be seen that in this method, the corresponding relationship between the slave node number and the protocol type is fixed, so when there is no corresponding relationship between the slave node number dialed by the device and the slave node number corresponding to the protocol that the device complies with, the device will not be supported.

Method 2: Set the corresponding relationship between the baud rate of the slave node and the protocol type, and the master node identifies slave unit devices that comply with different protocol types through the baud rate of the slave node. For example, there are slave unit device A and device B that comply with different protocol types. Set the baud rate of the slave node corresponding to the protocol type that device A complies with to 15000. When the slave node where device A is located sends a message to the master node, the master node The node recognizes device A through the slave node's baud rate of 15000, and finds the upper layer application program of device A to complete the support for device A.

If in actual transmission, the baud rate of device A is 9600, that is, there is no correspondence between the baud rate of device A’s slave node and the protocol type 1 that device A complies with, then device A will not be supported; if it complies with protocol type 2 The transmission baud rate of device B is 15000, because there is no corresponding relationship between the protocol type 2 complied with by device B and the slave node baud rate of 15000, then device B will not be supported. It can be seen that in this method, the corresponding relationship between the slave node baud rate and the protocol type is fixed, so when the actual transmission baud rate of a certain device does not correspond to the slave node baud rate corresponding to the protocol complied with by the device relationship, the device will not be supported. It can be seen that in the existing master-slave communication protocol, the master node implements support for slave unit devices of different protocol types through the slave node identifier. However, since the corresponding relationship between the slave node ID and the protocol type is fixed, when there is no corresponding relationship between the actual ID of the slave node and the protocol type, the master node cannot support the slave unit device on the slave node, which causes the master node to The support rate of the unit device is low, and it cannot adapt to the change and expansion of the unit device.

It can be seen that in the prior art, even if the protocol type complied with by the slave unit device does not change, as long as the slave node identifier changes, the master node cannot support the slave unit device on the slave node.

Moreover, in the master-slave communication protocol, the process of message interaction between the master node and the slave node is divided into two parts: the master node side and the slave node side. The master node side and the slave node side maintain a state machine respectively. Through the state machine Complete message sending and receiving.

Fig. 2 is a schematic diagram of a master-slave communication state machine of a master node. Referring to Fig. 2, in the existing master-slave communication protocol, the master node state machine has five states in total, wherein, the idle state 201 is a state common to the data sending and receiving process; the waiting query response state 202 and the waiting data receiving state 203 are used for Data receiving process; waiting for transmission response state 204 and waiting for receiving response state 205 are used for data sending process. The common state of the state machine of the master node is the idle state 201, and the idle state 201 has a cycle attribute, and the cycle attribute has two values: query cycle and transmission cycle.

In the existing master node message receiving process, the master node sends a query command to the slave node in the query cycle of the idle state 201; in the waiting query response state 202, it receives the query response sent back from the slave node; in the waiting to receive data state 203 Receive data packets sent from the node.

In the existing master node message sending process, the master node sends a transmission command to the slave node in the transmission cycle of the idle state 201; sends a data message to the slave node in the waiting transmission response state 204; Receive the received message response from the slave node.

Fig. 3 is a schematic diagram of a master-slave communication state machine of a slave node. Referring to Fig. 3, in the existing master-slave communication protocol, the slave node state machine has four states in total, wherein, the waiting command state 301 is the common state of data sending and receiving flow; the waiting receiving command state 302 and waiting receiving response state 303 are used in the data sending process; the waiting to receive data state 304 is used in the data receiving process. The general state of the slave node state machine is the waiting command state 301, and the waiting command state 301 has a periodic attribute, which is opposite to that of the idle state 201 of the master node state machine.

In the existing slave node message sending process, the slave node sends a query response to the master node in the waiting command state 301; sends a data message to the master node in the waiting to receive command state 302; Response to received message from the node.

In the existing message reception of the slave node, the slave node receives the transmission command of the master node in the waiting command state 301 ; and receives the data message sent by the master node in the waiting data receiving state 304 .

Contents of the invention

In view of this, the object of the present invention is to provide a method for the master node to support slave unit devices of different protocol types on the slave node, so that the master node can find the upper layer application program of the slave unit device through the protocol type that the slave unit device complies with.

In order to achieve the above object, the technical solution of the present invention is achieved in that:

The master node supports the method of slave unit devices of different protocol types on the slave node, pre-set the message content key value and message content mask of each protocol type slave unit device in the master-slave communication protocol, and establish the same protocol type slave unit The corresponding relationship between the message content mask of the device, the key value of the message content and the upper layer application program, the method includes the following steps:

A. The master node receives the message sent by the slave node;

B. Select the message content mask of a protocol type that has not been selected, and obtain the message content key value in the message by the selected message content mask;

C. Comparing the obtained message content key value with the message content key value of the protocol type described in step B, if the obtained message content key value is the same as the message content key value of the protocol type described in step B, then Execute step E, if the obtained message content key value is different from the message content key value of the protocol type described in step B, and there is a message content mask that has not been selected, return to step B, if the obtained message The content key value is different from the message content key value of the protocol type described in step B, and the message content masks of all protocol types have been selected, then step D is performed;

D. The master node discards the message, prompts an alarm message, and ends the process;

E. Select the upper-layer application program corresponding to the message content key value of the protocol type described in step B as the upper-layer application program of the slave unit device on the slave node.

The step of setting the message content key includes: setting the message content in the message that can uniquely identify the protocol type that the slave unit device complies with when communicating with the master unit device as the message content key value of the protocol type.

The step of setting the message content mask includes: setting the message content mask to be composed of an address offset and a mask value, and setting the address offset of the message content mask according to the message content key value and mask values.

The step of setting the address offset of the message content mask according to the message content key value includes: setting the address offset of the message content mask as the word where the message content key value is located in the message Node minus one.

The step of setting the mask value of the message content mask according to the message content key value includes: setting the number of bytes of the mask value as the number of bytes of the message content key value, and setting the number of bytes of the mask value Each byte bit is an all-ones value in hexadecimal.

The step of obtaining the message content key value in the message by the message content mask described in step B includes: offsetting the pointer for determining the message content key value, and the offset of the pointer is the message content The value of the address offset in the mask, and then select the byte pointed by the pointer as the start bit of the message content key value in the current message, and select the byte number of the mask value in the message content mask as The number of bytes of the message content key value in the current message, and the selected message content key value and the mask value of the message content mask to obtain the message content key value in the message.

The method further includes: after the master node receives the message from the slave node in the step A, it first searches for the slave node number in the message, and judges whether there is a record of the slave node number, if there is no record of the slave node number, then use the message as the first message, and save the slave node number in the first message, then carry out the steps B to E, and then set up the saved first message slave node number and the If there is a record of the slave node number corresponding to the upper-layer application program selected in step E, the upper-layer application program corresponding to the slave node number is directly selected without performing steps B to E.

Described step A comprises the following steps:

a. The master node sends a query command to the slave node during the query period of the idle state, and then migrates to the state of waiting for the query response;

b. The slave node receives the query command from the master node in the state of waiting for commands, and if there is a data message, it sends the data message to the master node, and then transitions to the state of waiting to receive a response;

c. In the state of waiting for the query response, if the master node receives the wrong data message, it will send an error response to the slave node and keep waiting for the query response state. If the master node receives the correct data message, it will send an error response to the slave node. Send a successful response from the node;

d. The slave node is in the state of waiting to receive a response. If the waiting response times out or receives a sending error response, it will resend the data message and remain in the state of waiting to receive a response. If the slave node receives a successful sending response, it will migrate to waiting command status.

The step of resending the data message from the slave node in step d and keeping it in the state of waiting to receive a response further includes: when the number of times the slave node resends the data message reaches the upper limit, then transition to the state of waiting for a command.

The retransmission times of the data message are preset according to the importance of the message.

It can be seen that the method of the present invention simplifies the message receiving process of the master node and the message sending process of the slave node, saves the command interaction process of returning the query response from the node and sending the data receiving command of the master node, and improves the relationship between the master node and the slave node. Inter-communication rate, and reduce the error probability of communication. The method of the present invention realizes the support of the master node to the slave unit devices of different protocol types by establishing a one-to-one correspondence between the message content mask of the same protocol type slave unit device, the message content key value and the upper layer application program, The disadvantage that the master node does not support the slave unit device on the slave node due to the change of the slave node ID is avoided. According to the method proposed by the present invention, by performing corresponding increase or change operations on the message content mask, message content key value, upper-layer application program and corresponding relationship of the slave unit device in the master-slave communication control block, it can also be adapted in time. Addition and change of slave unit devices on slave nodes.

Description of drawings

Figure 1 is a schematic diagram of the relationship between master and slave nodes;

Fig. 2 is a schematic diagram of a master-slave communication state machine of a master node in the prior art;

Fig. 3 is a schematic diagram of a master-slave communication state machine of a slave node in the prior art;

Fig. 4 is the flowchart of the inventive method;

Fig. 5 is the schematic diagram of the master-slave communication state machine of master node in the method of the present invention;

Fig. 6 is a schematic diagram of the master-slave communication state machine of the slave node in the method of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Pre-set the message content key value and message content mask of each protocol type slave unit device, and establish the relationship between the message content mask, message content key value and upper-layer application program of the same protocol type slave unit device Corresponding relationship, in which, the key value of the message content uniquely identifies the message content of the protocol type that the slave unit device and the master unit device follow when interacting with the message; the message content mask is composed of an address offset and a mask value , set the address offset of the message content mask to be the byte of the message content key value corresponding to the message content mask minus one, and set the mask of the message content mask The number of bytes of the code value is the number of bytes of the key value of the message content corresponding to the message content mask, and each byte of the mask value is a value of all ones in hexadecimal.

In the master-slave communication protocol, it is stipulated that the message content key value of the slave node message is obtained through the message content mask, and the message content key value and the same message content key value as the obtained message content key value are searched in the master-slave communication control block. The upper layer application program of the slave unit device on the slave node corresponding to the found message content key value.

Because the handshake character can uniquely identify the protocol type, the handshake character is set as the message content key value in this embodiment.

For example, there is a slave unit device C that complies with the protocol type ①, the handshake character of the protocol type ① is “HD”, and the handshake character “HD” is set as the message content key value of the protocol type ①. The handshake character "HD" is located in the third byte of the message, then set the message content mask of the protocol type ① according to the handshake character "HD", and the handshake character "HD" is located in the message The byte bit is subtracted by one to get the address offset 2 of the message content mask, and the byte number of the handshake character "HD" is 2, so the mask value of the message content mask is 16 bytes with a byte number of 2 The value of all ones in base, that is, 0xFFFF.

Fig. 4 is a flowchart of the method of the present invention. Referring to Fig. 4, the method for realizing the slave unit device C of the master node supporting the protocol type ① specifically includes the following steps:

Step 401: After receiving the query command from the master node, the slave node sends a message to the master node.

Step 402: the master node receives the message sent by the slave node.

Step 403: The master node finds the slave node number in the message, and judges whether the slave node number has a saved record. If there is a saved record, execute step 404. If there is no saved record, execute step 405.

Step 404: The master node searches for the upper-layer application program of the slave unit device corresponding to the slave node number according to the slave node number, and ends this process.

Step 405: the master node takes the received message as the first message, and saves the slave node number in the first message.

Step 406: In the master-slave communication control block, select a message content mask of a protocol type that has not been selected, and obtain the message content key value in the first message according to the selected message content mask, for example, select The message content mask of protocol type ①, the address offset of the message content mask is 2, and the pointer used to determine the key value of the message content in the message is offset, and the offset of the pointer is the message The value of the address offset in the content mask is 2, and then the third byte pointed by the pointer is selected as the start bit of the message content key value in the first message, because the mask value in the message content mask If the number of bytes of 0xFFFF is 2, set the number of bytes of the message content key value in the message to 2, and then compare the selected message content key value with the mask value 0xFFFF of the message content mask. and to obtain the packet content key value of the first packet.

Step 407: Compare the message content key value of the first message with the message content key value "HD" of the protocol type ①, and judge the message content key value of the first message and the message content key of the protocol type ① Whether the value "HD" is the same, if not, go to step 408, and if they are the same, go to step 410.

Step 408: Determine whether there is a message content mask of the protocol type not selected in the master-slave communication control block, if yes, return to step 406, if not, execute step 409.

Step 409: the master node discards the message from the slave node, prompts an alarm message, and ends the process.

Step 410: Select the upper-layer application program corresponding to the message content key value of the protocol type ① as the upper-layer application program of the slave unit device C on the slave node, and establish the slave node number in the first message and the selected slave node. Correspondence between the upper layer applications of the slave unit device C.

In order to increase the communication rate between the master node and the slave node, and reduce the error probability during communication, a preferred embodiment is: in step 401, the master node sends a query command to the slave node, and after the slave node receives the query command, The process of sending messages to the master node is simplified, that is, the message receiving process of the master node and the message sending process of the slave node are simplified, and the secondary command interaction process between the master node and the slave node is omitted.

Fig. 5 is the schematic diagram of master-slave communication state machine of master node in the method of the present invention, Fig. 6 is the schematic diagram of master-slave communication state machine of slave node in the method of the present invention, below in conjunction with Fig. 5 and Fig. 6 introduction simplified master node message reception Process and slave node message sending process.

In the message receiving process of the master node, the waiting data receiving state 203 of the state machine of the master node is removed, and at the same time, the data receiving command sent by the master node to the slave node is cancelled.

The message receiving process of the master node is: the master node sends a query command to the slave node in the query period of the idle state 201, then migrates to the waiting query response state 202, and waits for the response sent back from the slave node; in the waiting query response state 202, If the master node waits for the response timeout or the response sent back from the slave node is a no-thing response indicating that there is no data to send, then the master node migrates to the idle state 201, and the period attribute migrates to the transmission period, if the master node receives the wrong datagram If the master node receives the correct data message, it will send a successful message to the slave node. Acknowledgment, then the master node transitions to the idle state 201, and the period attribute transitions to the transmission period.

Correspondingly, in the message sending process of the slave node, the state machine of the slave node waiting to receive the command 302 is removed, and the busy response sent from the slave node to the master node is cancelled.

The message sending process of the slave node is: the slave node receives the query command from the master node in the waiting command state 301, if the slave node has no data message to send to the master node, it sends a no-thing response to the master node, and at the same time, the slave node Node remains in waiting command state 301, if slave node has data message to send to master node, then send this data message to master node, then transfers to waiting to receive response state 303 from node; In waiting to receive response state 303, If the slave node waits for the response timeout or receives an error response to send, then resend the data message, the number of retransmissions of the data message can be preset, and at the same time, the slave node remains in the state of waiting to receive the response 303, if the slave node receives the send If the response is successful or the number of retransmissions of the data message exceeds the upper limit, then the slave node will migrate to the waiting command state 301 .

In a word, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1, the host node support from the node the different agreement type from the method for unit, it is characterized in that, in the master-slave communication agreement, set message content key assignments and the message content mask of each protocol type in advance from unit, and set up same protocol type from the corresponding relation between message content mask, message content key assignments and the upper level applications three of unit, this method may further comprise the steps:

A, host node receive the message of sending from node;

B, choose the message content mask of a protocol type of not selecting for use, and obtain message content key assignments in the message by the message content mask of choosing;

C, the message content key assignments of acquisition and the message content key assignments of the described protocol type of step B are compared, if the message content key assignments that obtains is identical with the message content key assignments of the described protocol type of step B, execution in step E then, if the message content key assignments that obtains is different with the message content key assignments of the described protocol type of step B, and there is the not message content mask of selected mistake, then return step B, if the message content key assignments that obtains is different with the message content key assignments of the described protocol type of step B, and all selected mistake of the message content mask of all protocol types, then execution in step D;

D, host node be packet loss, prompt alarm information, and process ends;

E, choose upper level applications that the message content key-value pair of the described protocol type of step B answers for from node from the upper level applications of unit.

2, method according to claim 1, it is characterized in that the step of described setting message content key assignments comprises: set in the message can unique identification during from unit and master unit devices communicating the message content of the protocol type of deferring to be the message content key assignments of this protocol type.

3, method according to claim 1, it is characterized in that, the step of described setting message content mask comprises: set the message content mask and be made up of address offset amount and mask value, and set the address offset amount and the mask value of message content mask according to the message content key assignments.

4, method according to claim 3, it is characterized in that the described step of setting the address offset amount of message content mask according to the message content key assignments comprises: the address offset amount of setting the message content mask is that message content key assignments residing byte position in message subtracts one.

5, according to claim 3 or 4 described methods, it is characterized in that, the described step of setting the mask value of message content mask according to the message content key assignments comprises: the byte number of setting mask value is the byte number of message content key assignments, and each byte position of setting mask value is a hexadecimal full value.

6, method according to claim 5, it is characterized in that, the described step by the message content key assignments in the message content mask acquisition message of choosing of step B comprises: will be used for determining that the pointer of message content key assignments is offset, the side-play amount of pointer is the value of address offset amount in the message content mask, choosing pointer indication byte position then is the start bit of message content key assignments in the current message, and the byte figure place of choosing mask value in the message content mask is the byte figure place of message content key assignments in the current message, then with the mask value of the message content key assignments chosen and message content mask with, obtain the message content key assignments in the message.

7, method according to claim 1, it is characterized in that, this method further comprises: after host node receives the message of sending from node in described steps A, search earlier in the message from node number, and judge whether this keeping records from node number, if there is not this keeping records from node number, then with this message as the literary composition of reporting for the first time, and preserve in this literary composition of reporting for the first time from node number, carry out described step B again to step e, the corresponding relation of the upper level applications that the literary composition of set up preserving then of reporting for the first time is chosen from node number and described step e, if this keeping records from node number is arranged, then do not carry out described step B to step e, directly choose and be somebody's turn to do from node number corresponding upper application program.

8, method according to claim 1 is characterized in that, described steps A may further comprise the steps:

A, host node to sending querying command from node, are moved to the inquiry response state of waiting for then in the polling cycle of idle condition;

B, receive the querying command that host node is sent at the wait command state, and data message is arranged, then send this data message, move to then and wait for and receive response status to host node from node;

C, host node are in waiting for the inquiry response state, if receive wrong data message,, and remain on the inquiry response state of waiting for then to sending the transmission wrong responses from node, if host node receives correct data message, then to send the transmission successful respond from node;

D, from node during wait for receiving response status, if wait acknowledge is overtime or receive the transmission wrong responses, retransmission data message then, and remain on and wait for and receive response status if receive the transmission successful respond from node, is then moved to the wait command state.

9, method according to claim 8, it is characterized in that, steps d is described from node retransmission data message, and remains on the step that wait for to receive response status and further comprise: reach the upper limit from the number of times of node retransmission data message, then move to the wait command state.

10, method according to claim 9 is characterized in that, the repeating transmission number of times of data message preestablishes according to the importance of message.

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