CN116383110A - A kind of Modbus communication module and communication method - Google Patents

Abstract

The invention discloses a Modbus communication module and a communication method, including a Modbus adaptation module respectively connected to a frequency converter and a PLC/upper computer; the Modbus adaptation module includes a processing module and a keyboard connected to the processing module, an RS485 interface on the primary side, and a secondary side RS485 interface and communication indicator light; the secondary side RS485 interface is provided with a signal isolation module connected to the PLC/host computer; the present invention completes two functional functions through a corresponding relationship between the primary side and the secondary side address, 1. Analyze the data of the side address, 2, and convert it into data corresponding to the original side address, and then write it into the inverter; update the real-time updated data of the original side to the secondary side accordingly; thus achieving a data interaction function , and through the parameter setting function of the keyboard, the address of the original side and the side can be changed according to the needs of various occasions, so that it can adapt to various occasions.

Description

A kind of Modbus communication module and communication method

technical field

The invention relates to the field of MODBUS communication of a frequency converter, in particular to a Modbus communication module and a communication method, which are mainly used in field equipment 485 bus processing in the industrial control industry to realize equipment update and replacement without modifying the original bus system.

Background technique

MODBUS communication is a one-to-many communication method, that is, there is only one master in a single network segment, and multiple slaves can be allowed, but to achieve master-slave communication, the master must know the register address of the slave device.

For some frequency conversion end customers, they are only at the level of using the workshop control system and field 485 bus equipment, and cannot modify the master station equipment in the system. When the equipment is damaged and a new replacement is urgently needed , the difference in the register address will make it unusable.

Contents of the invention

The technical problem to be solved by the present invention is to provide a Modbus communication module and a communication method; to solve the problem that the equipment cannot be used due to the difference of the MODBUS register address of the new and old equipment.

The Modbus communication module of the present invention is realized through the following technical solutions: comprise the Modbus adaptation module that respectively connects the frequency converter and PLC/host computer; Side RS485 interface and communication indicator light; secondary side RS485 interface is equipped with a signal isolation module connected to PLC/host computer;

The Modbus adapter module is equipped with a secondary side data processing module of the MODBUS adaptation module and a primary side data processing module of the MODBUS adaptation module; the secondary side data processing module of the MODBUS adaptation module is connected to the secondary side RS485 interface; the primary side data processing module of the MODBUS adaptation module The module is connected to the primary RS485 interface.

The Modbus communication method of the present invention is realized through the following technical solutions:

The secondary data processing module of the MODBUS adapter module specifically includes the following steps:

S1, receive PLC data, enter S2;

S2. Determine whether the station number of the equipment is correct, if it is correct, enter S3, and if it is incorrect, enter S13;

S3, Modbus data verification, enter S4;

S4, judging whether the verification is successful, if successful, enter S5, and if unsuccessful, enter S13;

S5. Find the matching address of the secondary side, and enter S6;

S6, judging whether the address exists, if it exists, enter S7, if it does not exist, enter S13;

S7, judge Modbus command code, carry out S8 and S9 and S10 simultaneously;

S8, 0x03 command, enter S11;

S9, 0x06 command, enter S14;

S10, 0x010 command; enter S11;

S11. Determine whether it is continuous, if S8 is continuous, enter S12, if S10 is continuous, enter S14; if S8 and S10 are not continuous, enter S13;

S12. Obtain the address data of the secondary side, and proceed to S15;

S13. Prepare fault response data, and enter S15;

S14. Data is written to the address, and the corresponding address write event flag of the original side is set;

S15, return the response data to the host computer;

The primary side data processing module of the MODBUS adapter module specifically includes the following steps:

S1, whether the sending busy bit is 1, if not sending, enter S2, and send, enter S7;

S2, the polling address is written into the event address bit, and enters S3;

S3, judging whether there is a writing event; if writing, enter S4, and if not writing, enter S5;

S4, write the data into the frequency converter, enter S6;

S5, cyclically read the frequency converter data, enter S6;

S6, the busy position is 1, enter S7;

S7, judging whether there is data reception, if yes, enter S8, otherwise end directly;

S8. Determine whether the data verification is successful, if yes, enter S9, otherwise end directly

S9, judging whether to write the command, if yes, enter S10, otherwise enter S11;

S10, clear the original side and write the event log, and end;

S11. Update the address data of the primary side register, and enter S12;

S12. Update the address data of the corresponding secondary register, and end.

The beneficial effects of the present invention are: through a corresponding relationship between the addresses of the primary side and the secondary side, two functional functions are completed:

1. Analyze the data of the secondary side address and convert it into data corresponding to the primary side address, and then write it into the inverter;

2. Update the data updated in real time on the primary side to the secondary side. In this way, a function of data interaction is achieved, and through the parameter setting function of the keyboard, the address of the original and secondary sides can be changed according to the needs of various occasions, so that it can adapt to various occasions, and it is a good solution to the problem of register addresses when the equipment is replaced. matching problem.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the schematic diagram of Modbus communication module;

Fig. 2 is a schematic diagram of the processing steps of the secondary side data processing module of the MODBUS adapter module;

Fig. 3 is a schematic diagram of the processing steps of the primary side data processing module of the MODBUS adaptation module.

Detailed ways

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification (including any appended claims, abstract and drawings), unless expressly stated otherwise, may be replaced by alternative features which are equivalent or serve a similar purpose. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

As shown in Figure 1, a kind of Modbus communication module of the present invention comprises the Modbus adaptation module that connects frequency converter and PLC/host computer respectively; Modbus adaptation module comprises processing module and the keyboard that connects processing module, primary side RS485 interface, The RS485 interface on the secondary side and the communication indicator light; the RS485 interface on the secondary side is equipped with a signal isolation module connected to the PLC/host computer;

The Modbus adapter module is equipped with a secondary side data processing module of the MODBUS adaptation module and a primary side data processing module of the MODBUS adaptation module; the secondary side data processing module of the MODBUS adaptation module is connected to the secondary side RS485 interface; the primary side data processing module of the MODBUS adaptation module The module is connected to the primary RS485 interface.

In this embodiment, the MODBUS adaptation module has a function menu structure, and the function parameters of the module are set through the keyboard, including the address corresponding to the primary side and the secondary side, the number of decimal points of the data of the primary side and the secondary side, the communication format and the station Address, after the parameter setting is completed, it can work normally; it mainly involves communication format parameters, primary side address setting, and secondary side address setting.

A kind of Modbus communication method of the present invention, as shown in Figure 2: this flow process is the flow process of secondary side data processing, and the role of secondary side is MODBUS slave station;

S1: The RS485 interface on the secondary side receives data from the PLC/host computer;

S2: Determine whether the received MODBUS station number matches the station number of the module, if not, jump to step S13;

S3: Perform CRC16 check on the received data;

S4: judging whether the CRC check is successful;

S5: After the data verification is successful, obtain the address information in the data and compare it with all secondary addresses;

S6: judging whether a matching address is found, if no matching address is found, jump to step S13;

S7: If a matching address is found, judge the function command of the data (0x03, 0x06, 0x10);

S8: If the function command is 0x03 (read multiple data), jump to step S11;

S9: if the function command is 0x06 (write single data), jump to step S14;

S10: If the function command is 0x10 (write multiple data), go to the next step;

S11: Judging whether the addresses in the continuous reading of multiple addresses/continuous writing of multiple addresses are continuous, if not continuous, jump to step S13;

S12: Obtain the data in the secondary address to prepare for the data response;

S13: prepare fault response data, jump to step S15;

S14: Write the received PLC data into the address of the secondary side, update the data of the corresponding address of the primary side and write the event flag bit;

S15: Return the data to the PLC, and the process ends;

As shown in Figure 3, the role of the original side of the process corresponds to the MODBUS master station for the inverter:

S1: Determine whether the sent busy flag is 1, if it is 1, then jump to step S7;

S2: Poll the write event flag bits of all addresses on the primary side;

S3: judging whether there is a writing event, if not, then jump to step S5;

S4: If there is a write event, write the original address data of the write event to the inverter;

S5: If there is no write event, read the data of the frequency converter in a loop to update the address data of the primary side and the corresponding address data of the secondary side;

S6: After the data is sent, the send busy flag is set to 1;

S7: judge whether there is data received, if not, the program ends;

S8: If there is data received, judge whether the data verification is successful, if the verification fails, the program ends;

S9: If the data verification is successful, determine whether it is a writing event;

S10: If it is a write event, clear the write event flag bit of the corresponding address on the original side, and the program ends;

S11: If it is a cyclic reading task, update the original address data;

S12: update the corresponding secondary side address data;

The present invention can be used as a communication device adapted to register addresses of MODBUS frequency converters of any manufacturer, and is mainly used in occasions where certain PLC or upper computer programs cannot be changed when some new frequency converters replace old ones. Through this device, new devices that support MODBUS communication can be easily connected to the communication bus without modifying the original register address in the PLC or the upper computer, and it is equipped with an isolation signal isolation circuit to enhance the anti-interference ability of the device.

The above is only a specific implementation of the present invention, but the scope of protection of the present invention is not limited thereto, and any changes or replacements that do not come to mind through creative work shall be covered within the scope of protection of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope defined in the claims.

Claims (2)

1. The utility model provides a Modbus communication module which characterized in that: the device comprises a Modbus adaptation module which is respectively connected with a frequency converter and a PLC/upper computer; the Modbus adaptation module comprises a processing module, a keyboard, a primary side RS485 interface, a secondary side RS485 interface and a communication indicator lamp, wherein the keyboard is connected with the processing module; a signal isolation module connected with a PLC/upper computer is arranged on the secondary side RS485 interface;

the Modbus adaptation module is provided with a secondary side data processing module of the ModBUS adaptation module and a primary side data processing module of the ModBUS adaptation module; the MODBUS adaptation module secondary side data processing module is connected with a secondary side RS485 interface; the MODBUS adaptation module primary side data processing module is connected with a primary side RS485 interface.

2. A Modbus communication module communication method is characterized in that: the secondary side data processing module of the MODBUS adaptation module specifically comprises the following steps:

s1, receiving PLC data, and entering S2;

s2, judging whether the equipment station number is correct, if so, entering S3, and if not, entering S13;

s3, modbus data verification, and entering S4;

s4, judging whether the verification is successful, if so, entering S5, and if not, entering S13;

s5, searching a secondary side matching address, and entering S6;

s6, judging whether the address exists, if so, entering S7, and if not, entering S13;

s7, judging Modbus command codes, and simultaneously carrying out S8, S9 and S10;

s8, 0x03 command (read multiple), and the process goes to S11;

s9, 0x06 command (write single), enter S14;

s10, 0x010 command (read multiple); entering S11;

s11, judging whether the continuous operation is carried out, if the continuous operation is carried out in S8, entering S12, and if the continuous operation is carried out in S10, entering S14; s8 and S10 are discontinuous, and S13 is entered;

s12, acquiring secondary side address data, and entering S15;

s13, preparing fault response data, and entering S15;

s14, writing data into the address, setting an address writing event flag bit corresponding to the primary side;

s15, returning response data to the upper computer;

the MODBUS adaptation module primary side data processing module specifically comprises the following steps:

s1, whether a transmission busy bit is 1 or not, entering S2 if not, and entering S7 if not;

s2, writing the polling address into an event address bit, and entering S3;

s3, judging whether a writing event exists or not; writing is performed, S4 is performed, and writing is performed, S5 is performed;

s4, writing the data into a frequency converter, and entering S6;

s5, circularly reading the data of the frequency converter, and entering S6;

s6, the busy position is 1, and S7 is entered;

s7, judging whether data are received or not, if yes, entering S8, and if not, directly ending;

s8, judging whether the data is successfully checked, if so, entering S9, otherwise, directly ending S9, judging whether to write in a command, if so, entering S10, otherwise, entering S11;

s10, clearing a primary side write event log, and ending;

s11, updating address data of a primary register, and entering S12;

s12, updating the address data of the corresponding secondary side register, and ending.

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