CN110851392B - Communication method and communication system based on Modbus RTU protocol - Google Patents
Communication method and communication system based on Modbus RTU protocol Download PDFInfo
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- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
- G06F13/38—Information transfer, e.g. on bus
- G06F13/42—Bus transfer protocol, e.g. handshake; Synchronisation
- G06F13/4282—Bus transfer protocol, e.g. handshake; Synchronisation on a serial bus, e.g. I2C bus, SPI bus
- G06F13/4286—Bus transfer protocol, e.g. handshake; Synchronisation on a serial bus, e.g. I2C bus, SPI bus using a handshaking protocol, e.g. RS232C link
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- G06F11/00—Error detection; Error correction; Monitoring
- G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
- G06F11/08—Error detection or correction by redundancy in data representation, e.g. by using checking codes
- G06F11/10—Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
- G06F11/1004—Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's to protect a block of data words, e.g. CRC or checksum
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Abstract
The invention provides a communication method and a communication system based on a Modbus RTU protocol, wherein the method comprises the steps that a host and a plurality of slave machines are connected on a Modbus RTU bus in parallel, and the host sends communication instructions to the slave machines simultaneously; and when the communication instruction is a query instruction, the slave machines sequentially send data to the host machine according to the slave machine address sequence in the query instruction, the first slave machine monitors the data sent by the slave machines, calculates a CRC (cyclic redundancy check) value and sends the CRC value to the host machine for checking. In Modbus RTU communication, the host can complete data interaction with a plurality of slave machines by only initiating communication once, so that the communication time of polling the slave machines by the Modbus RTU host is shortened, and the communication efficiency is improved.
Description
Technical Field
The invention relates to the technical field of computer communication, in particular to a communication method and a communication system based on a Modbus RTU protocol.
Background
Modbus is a serial communication protocol published by Modicon corporation (now Schneider Electric) in 1979 for communication using a Programmable Logic Controller (PLC). Modbus has become an industry standard (De factor) for industrial field communication protocols and is now a common connection between industrial electronic devices.
The Modbus RTU is one of Modbus communication protocols, and the Modbus RTU generally adopts an RS-485 bus, which is a communication protocol of a serial link. The Modbus RTU protocol provides for only one master device on the bus with one or more (up to 247) slave devices. In Modbus RTU communication, a host computer firstly sends a communication command, and a slave computer receives the back command and then returns data according to the command requirement.
When there are multiple slaves in the bus, the master generally uses a polling method to implement data interaction. However, when the number of slaves is large, the time for the master to poll once is long, and the communication efficiency is low.
Disclosure of Invention
In view of the above, the main objective of the present invention is to provide a communication method and a communication system based on a Modbus RTU protocol, in Modbus RTU communication, a host only needs to initiate one communication to complete data interaction with multiple slaves, so that communication time for polling multiple slaves by the Modbus RTU host is reduced, and communication efficiency is improved.
The invention adopts the technical scheme that a communication method based on a Modbus RTU protocol is applied to a master-slave communication system and comprises the following steps:
the method comprises the following steps that a host and a plurality of slave machines are connected on a Modbus RTU bus in parallel, and the host sends communication instructions to the slave machines at the same time;
and when the communication instruction is a query instruction, the slave machines sequentially send data to the host machine according to the slave machine address sequence in the query instruction, the first slave machine monitors the data sent by the slave machines, calculates a CRC (cyclic redundancy check) value and sends the CRC value to the host machine for checking.
The main machine and the plurality of slave machines are connected in parallel on a Modbus RTU bus, when the main machine needs to communicate with each slave machine, a communication instruction is sent to each slave machine through the Modbus RTU bus only once, each slave machine can send data to the main machine according to the address sequence in the communication instruction, in the process that each slave machine sends data, a first slave machine intercepts the data sent by each slave machine and calculates a CRC (cyclic redundancy check) value, and after all the slave machines finish data sending, the first slave machine sends the calculated CRC value to the main machine for checking, so that whether the intercepted data sent by each slave machine is consistent with the data received by the main machine or not is verified, and the accuracy of data transmission is guaranteed.
The first slave is the first slave in the slave address sequence in the inquiry instruction.
Therefore, in the master-slave communication system, the address of each slave and the address of the register thereof need to be configured, the communication command sent by the host includes the address of each slave, so that the slave can be retrieved, each slave executes the command of the host according to the corresponding address, when sending data, the slave located at the first bit in the communication command performs interception and calculation of a CRC check value on the data sent by each slave, and sends the calculated CRC check value to the host, so that the data packet received by the host can be complete and meet the Modbus RTU protocol requirement.
Wherein, when the communication command is a register query command,
the data sent by the first slave machine to the host machine comprises a communication ID, a function code, the number of bytes of a register and a value of a corresponding register;
the data sent to the host by each slave except the first slave comprises the value of the corresponding register;
and the first slave machine also sends the calculated CRC value to the host machine after all the slave machines finish sending the register values.
Therefore, when the communication instruction is an inquiry register instruction, the data packet conforming to the Modbus RTU protocol includes a communication ID, a function code, the number of bytes of the register, the value of the register in each slave, and a check code.
In a further improvement, when the first slave monitors that data is not sent by a slave within a set time, the first slave judges that the communication of the slave is overtime, and sends 0xff to the master instead of the value of the corresponding register of the slave.
Therefore, when the first slave machine detects that a certain slave machine does not send data in a specified time, the fault of the slave machine is judged, at the moment, the first slave machine sends two 0xff (one register is displayed by two bytes in a general case) to the master machine to replace the data which should be sent by the fault slave machine, because the Modbus RTU uses serial port communication, when the first slave machine sends 0xff, the parity check bit of the data sent by the serial port can be changed, the master machine detects that the received data is abnormal, the data sent by the serial port can be analyzed to obtain the 'the sent data is 0 xff' and the slave machine is judged to be faulty according to the sequence of the slave machines which send the data currently.
Further improvement, still include:
the master machine locates the slave machine which currently transmits data by detecting the level value of the enabling bit of each slave machine, and when the enabling bits of a plurality of slave machines are simultaneously low level and lower than the level value when one slave machine transmits data, the master machine processes the data transmitted by the plurality of slave machines in an abnormal mode.
In the above way, by adding a signal line to the Modbus RTU bus, the master computer detects the level value when each slave computer transmits data, and according to the difference of the level of the input port when a single slave computer transmits data and a plurality of slave computers transmit data, it locates which slave computer or register has address conflict, and processes the data transmitted by the slave computers with the address conflict.
Wherein the exception handling comprises:
and judging the address conflict of the plurality of slave machines, and ignoring the data sent by the plurality of slave machines.
Therefore, when the host detects that the level values of the multiple slaves are obviously lower than the level value when a single slave sends data, the multiple slaves can be positioned, and therefore the situation that the multiple slaves have address conflict and send data at the same time is judged, and the host can choose to ignore the data sent by the multiple slaves when processing the data.
Further improvement, still include:
when the communication command is a setting command, each slave computer responds to the setting designation to set the value of the register.
Therefore, when the communication command sent by the master is the setting command, each slave can simultaneously respond to the setting command, analyze the value of the corresponding register in the setting command and set the register.
Based on the communication method, the invention also provides a communication system based on the Modbus RTU protocol, which comprises the following steps:
the system comprises a host, a plurality of slave machines and a Modbus RTU bus;
the main machine and the plurality of slave machines are connected on the Modbus RTU bus in parallel, and the main machine simultaneously sends communication instructions to the plurality of slave machines through the Modbus RTU bus.
In the communication system, the host and the plurality of slave machines are connected in parallel to the Modbus RTU bus, after the slave machines and the registers called by the slave machines are configured to different addresses, the host simultaneously sends a communication instruction containing the addresses of the slave machines and the addresses of the registers to the slave machines through the Modbus RTU bus, and the slave machines respond to the communication instruction of the host and perform data interaction with the host machine.
The system is further improved and also comprises signal wires connected between the master machine and a plurality of slave machines;
when each slave responds to the host command to send data, the level value of the enable bit of each slave is pulled down;
the master machine detects the level value of each slave machine enabling bit through the signal wire.
In the above, by adding a signal line to the Modbus RTU bus, the master device detects the level value when each slave device transmits data, and further determines which slave devices or registers have address conflicts according to the difference in level of the input port when a single slave device transmits data and a plurality of slave devices transmit data, and the master device can choose to ignore the data transmitted by the plurality of slave devices when processing data.
Preferably, the Modbus RTU bus comprises an RS-485 serial port bus, and the communication format of the RS-485 serial port bus is set as follows: a 1bit start bit, an 8bit data bit, a 1bit parity bit, and a 1bit end bit.
In the above way, an RS-485 serial port bus of a Modbus RTU protocol can be selected for communication connection between the host and the plurality of slave machines.
Drawings
FIG. 1 is a schematic diagram of a Modbus RTU protocol-based communication system according to the present invention;
FIG. 2 is a flow chart of a communication method based on a Modbus RTU protocol according to the present invention;
FIG. 3 is a diagram illustrating a plurality of slaves replying to a data packet of a master according to the present invention;
FIG. 4 is a diagram of the hardware connection of the master device to detect the level values of several slave devices according to the present invention.
Detailed Description
The communication method and the communication system based on the Modbus RTU protocol according to the present invention are described in detail with reference to fig. 1 to fig. 4.
As shown in fig. 2, an embodiment of the present invention provides a communication method based on a Modbus RTU protocol, which is applied to the communication system shown in fig. 1, where the communication system includes a host and one hundred slaves that are to perform Modbus RTU communication, and the host communicates with the one hundred slaves through an RS-485 bus of the Modbus RTU protocol;
specifically, the communication method comprises the following steps:
s100: the method comprises the following steps that a host and a plurality of slave machines are connected on a Modbus RTU bus in parallel, and the host sends communication instructions to the slave machines at the same time;
specifically, the one hundred slaves have the same communication ID, but the addresses of the slaves are different from the addresses of the internal registers, for convenience of description, the addresses of the one hundred slaves are set to be slave 1 to slave 100, the ID of the master is set to be 1 (corresponding to the first byte 0x01 of the communication command), when the master initiates a communication command, the slaves perform packetization (if they are inquiry commands) or depacketization (if they are set commands) according to the protocol format, and the command replied to the master is guaranteed to conform to the Modbus RTU protocol.
S200: when the communication instruction is a query instruction, the slave machines sequentially send data to the host machine according to the slave machine address sequence in the query instruction, the first slave machine monitors the data sent by the slave machines, calculates a CRC (cyclic redundancy check) value and sends the CRC value to the host machine for checking;
in this embodiment, when the communication instruction sent by the host is a register query instruction, the query instruction is that the ID of the host is 1 (corresponding to the first byte 0x01 of the communication instruction), the values of 1 register in each slave are read (the function code is 0x03, corresponding to the second byte of the instruction), it is assumed that the value of the address of the register 1 of the slave 1 is to be read, the value of the address of the register 2 of the slave 2 is to be read, the value of the address of the register 3 of the slave 3 is to be read, and the process proceeds sequentially, and the value of the register 100 of the slave 100 is to be read, the query instruction sent by the host is "0 x 010 x 030 x 000 x 010 x 000 x 640 x 150 xEA", and the meaning of the query instruction is "to be read from the register 1 of the slave 1 to the register 100";
as shown in FIG. 3, assume that the value stored by the slave 1-100 corresponding register 1-100 is exactly the value 1-100. After the host sends an instruction, all the slaves 1 to 100 receive the instruction, the slaves 1 to 100 sequentially transmit data to be transmitted to the host through a bus to form a data packet, the data sent by the slave 1 includes "communication ID 0x01, function code 0x03, remaining byte number 0xC8 and value 0x 000 x 01" of the corresponding register, when the slave 2 to 100 sends the data (value of the corresponding register), the slave 1 is also responsible for intercepting the data sent by the slaves 2 to 100 and calculating a check value, after all the slaves complete sending the data, the slave 1 sends the calculated check value to the host, and the host sends the received data packet to be a complete data packet according to the bus RTU protocol requirement according to the sending sequence, specifically "0 x 010 x 030 xC 80 x 000 x 020 x 000 x03 … … 0x 640 x 310 x 3", wherein "0 x 000 x 02" is data transmitted to the slave 2 through the bus, wherein "0 x 000 x 03" is the data transmitted from the slave 3 to the master via the bus, … … "0 x 000 x 64" is the data transmitted from the slave 100 to the master via the bus, and "0 x 310 xE 3" is the upper and lower bits of the check code calculated by the slave 1.
In the process of the slave machine replying data according to the master inquiry command, the following two fault conditions generally occur: 1) a slave is missing; 2) two or more slave addresses and register numbers are the same. Two solutions to the failure are given in turn:
1) a slave is missing (or fails) and cannot recover data;
the RS-485 serial port communication format of the Modbus RTU protocol is set as follows: a 1bit start bit, an 8bit data bit, a 1bit parity bit, and a 1bit end bit.
If the slave n fails, after the slave n-1 finishes sending data, the slave 1 monitors that the slave n does not send data, and judges that the communication is overtime (the time of 0.5bit specified by the baud rate), and at this time, the slave 1 sends 20 xff (one register is displayed by two bytes in general) to the host. Because the Modbus RTU uses serial communication, when the slave 1 sends 0xff, the parity check bit of the data sent by the serial port can be changed, the host detects the received data abnormality, the data sent by the serial port can be used for analyzing that the sent data is 0xff and deducing that the slave n is a fault, and other information are processed, the slave n +1 continues to send own data, after the register data of all the slaves are sent, the slave 1 calculates the CRC value, and the data sent by the slave with the fault is replaced by 0 xff. By analogy, this approach can also be used to resolve when multiple slaves fail.
2) The addresses of two or more slave machines are the same with the register number, and the host machine cannot judge which is the effective value;
as shown in fig. 4, since there are multiple slaves in the master-slave communication system, it is inevitable that the addresses of two or more slaves are the same or the addresses of registers are the same, and at this time, the two or more slaves may transmit data simultaneously, and the master cannot determine which of the received data is a valid value, based on this, the embodiment of the present invention further adds a signal line to the Modbus RTU bus, and the master detects that the levels of the input ports are different when the single slave replies data and the multiple slaves reply data, and further locates which slave has a problem, so the master can define the data transmitted by the slave as invalid, and the specific determination process is as follows:
in the specific determination process, when the slave 1 wants to send data, the slave 1 pulls down the enable bit to output a low level, and the enable bits of other slaves still output a high level, so that the master detects that the enable bit of the slave 1 is a low level, and determines that the data is sent by the slave 1. Namely: the slave enable bit to transfer data to the master is low and the outputs of the other slaves are high. If the slave machines 3 and 4 simultaneously send data to the master machine, the enabling bits of the slave machines 3 and 4 are both low level, at this time, the slave machines 3 and 4 belong to a parallel connection state, and according to the rule of parallel connection of resistors, the resistance value is equal to one half of the resistance value when a single slave machine is pulled down. The master machine will detect that the level of the slave machines 3 and 4 is obviously lower than the voltage value when a single slave machine sends data, and accordingly judge that a plurality of slave machines send data currently, so that the slave machines 3 and 4 send data at the same time. The master detects this and therefore determines that the data sent from the slaves 3, 4 is invalid and ignores the invalid data when processing it.
S300: when the communication instruction is a setting instruction, each slave computer responds to the setting instruction to set the value of the register of the slave computer;
in this step, when the communication command sent by the master is a register setting command, each slave receives the command through the bus at the same time, and analyzes the value of the register corresponding to each slave in the command, and each slave sets the value of the register corresponding to each slave in the register, thereby completing the simultaneous setting of the master on a plurality of slaves.
It should be noted that, no matter whether the communication command is an inquiry command or a setting command, the addresses of the slaves and the applied register addresses cannot be repeated, otherwise the values of the transferred registers will be confused, and as long as the slaves with different addresses select the registers with different addresses for transmission communication, the master can simultaneously communicate with a plurality of slaves.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (2)
1. A communication method based on a Modbus RTU protocol is applied to a master-slave communication system, and the master-slave communication system comprises:
the system comprises a host, a plurality of slave machines and a Modbus RTU bus; the Modbus RTU bus comprises an RS-485 serial port bus, and the communication format of the RS-485 serial port bus is set as follows: 1bit start bit, 8bit data bit, 1bit odd check bit and 1bit end bit;
the main machine and the plurality of slave machines are connected in parallel on the Modbus RTU bus, and the main machine simultaneously sends communication instructions to the plurality of slave machines through the Modbus RTU bus;
the system also comprises a signal wire connected between the host and a plurality of slave machines; when each slave responds to the host command to send data, the level value of the enable bit of each slave is pulled down; the host computer detects the level value of each slave computer enable bit through the signal line;
the method comprises the following steps:
the method comprises the following steps that a host and a plurality of slave machines are connected on a Modbus RTU bus in parallel, and the host sends communication instructions to the slave machines at the same time;
when the communication instruction is a query instruction, the slave machines sequentially send data to the host machine according to the slave machine address sequence in the query instruction, the first slave machine monitors the data sent by the slave machines, calculates a CRC (cyclic redundancy check) value and sends the CRC value to the host machine for checking;
when the communication instruction is an instruction for inquiring the register, the data sent by the first slave machine to the host machine comprises a communication ID, a function code, the number of bytes of the register and a value of a corresponding register; the data sent to the host by each slave except the first slave comprises the value of the corresponding register; after all the slave machines complete the transmission of the register values, the first slave machine also transmits the calculated CRC value to the host machine; when the first slave machine monitors that a certain slave machine does not send data within the set time, judging that the communication of the slave machine is overtime, and sending 0xff to the host machine instead of the value of the corresponding register of the slave machine; the master machine positions the slave machines which currently transmit data by detecting the level value of the enabling bit of each slave machine, and when the enabling bits of a plurality of slave machines are simultaneously low level and lower than the level value when one slave machine transmits data, the master machine judges the address conflict of the plurality of slave machines and ignores the data transmitted by the plurality of slave machines;
and when the communication command is a setting command, each slave computer responds to the setting command to set the value of the register of the slave computer.
2. The method of claim 1, wherein the first slave is the first slave in the slave address order in the inquiry instruction.
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| CN114500461B (en) * | 2021-12-24 | 2023-05-16 | 珠海格力电器股份有限公司 | Communication method, device, storage medium, upper computer, lower computer and communication system |
| CN114422288B (en) * | 2021-12-29 | 2024-03-19 | 厦门诚通达智能科技有限公司 | Communication system based on Modbus protocol |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104954096A (en) * | 2015-04-23 | 2015-09-30 | 河南科技大学 | One-master multi-slave high-speed synchronous serial communication data transmission method |
| CN105512704A (en) * | 2015-12-18 | 2016-04-20 | 上海步科自动化股份有限公司 | Electronic tag Modbus communication system and warehousing system |
| CN106533621A (en) * | 2016-11-15 | 2017-03-22 | 合肥工业大学智能制造技术研究院 | Communication method for monitoring permanent magnet synchronous motor in real time based on simplified MODBUS protocol |
| CN108733604A (en) * | 2018-05-11 | 2018-11-02 | 深圳市脉联电子有限公司 | A kind of 485 bus intelligent expansion method and devices based on modbus communications protocol |
| CN109240219A (en) * | 2018-10-16 | 2019-01-18 | 湖南戈人自动化科技有限公司 | A kind of multi-axis motion controller |
| CN109450756A (en) * | 2018-10-18 | 2019-03-08 | 南京海桐环境科技有限公司 | A kind of ModbusRTU signal procedure based on SIMATIC S7-200 SMART |
-
2019
- 2019-11-13 CN CN201911109224.5A patent/CN110851392B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104954096A (en) * | 2015-04-23 | 2015-09-30 | 河南科技大学 | One-master multi-slave high-speed synchronous serial communication data transmission method |
| CN105512704A (en) * | 2015-12-18 | 2016-04-20 | 上海步科自动化股份有限公司 | Electronic tag Modbus communication system and warehousing system |
| CN106533621A (en) * | 2016-11-15 | 2017-03-22 | 合肥工业大学智能制造技术研究院 | Communication method for monitoring permanent magnet synchronous motor in real time based on simplified MODBUS protocol |
| CN108733604A (en) * | 2018-05-11 | 2018-11-02 | 深圳市脉联电子有限公司 | A kind of 485 bus intelligent expansion method and devices based on modbus communications protocol |
| CN109240219A (en) * | 2018-10-16 | 2019-01-18 | 湖南戈人自动化科技有限公司 | A kind of multi-axis motion controller |
| CN109450756A (en) * | 2018-10-18 | 2019-03-08 | 南京海桐环境科技有限公司 | A kind of ModbusRTU signal procedure based on SIMATIC S7-200 SMART |
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