TWI445320B - A modbus crc check code generation method - Google Patents

Description

Modbus CRC check code generation method

A Modbus CRC check code generation method, in particular, applied to various facility controller communication systems, such as a communication system of a nuclear energy level controller.

In factory automation systems, such as nuclear power plants, manufacturing or petrochemical plants, the correctness of the information exchange or transmission process is very important to the requirements of the safe operation. Therefore, the communication process of the network must provide verification function to detect network errors. When a fault occurs, the corresponding programmable logic controller must be notified to take appropriate action, network communication.

The Modbus protocol is a common protocol for the automation industry. It was originally designed as a serial line protocol in the late 1970s. However, in the automation industry, it has now become an existing standard and is used in a conventional interface in all smart automation devices.

CRC is commonly used in error checking techniques for between data systems being transferred or between processing functions. Traditional hardware CRC generators are generally a fixed length polynomial. These hardware CRC generators can only use a CRC equation to calculate a CRC. A single CRC equation can be applied to a particular device for a single application. However, the single CRC equation does not provide the ability to detect errors for all types of data. Using more than one CRC equation may require multiple CRC generator development tools, each CRC generator needs to be implemented by a single hardware. This solution is undesirable because additional transistors must increase the size of the circuit. And the cost of the wafer.

The invention automatically generates the Modbus CRC-16 format required by the hardware description language by means of software, that is, the generated format can be applied to the communication system design of the nuclear energy level controller.

In order to solve the problem that multiple CRC generators may be required to use more than one CRC equation, each CRC generator needs to be implemented by one hardware. The present invention proposes a Modbus CRC check code generation method, which can be used for any input data. The length produces a set of Modbus CRC-16 check codes.

The invention provides a Modbus CRC check code generating method, which comprises the following steps:

A) Calculate the input data length (d), and divide the input data length (d) by 8 to obtain a loop number, wherein the input data length (d) is a minimum of 8 bits;

B) Define a data matrix m=[m(8*d) m(8*d-1) m(8*d-2) ...m(3) m(2) m(1)] for storage Input data, where m(j) is the value of the jth bit of the input data;

C) define a check code matrix crc=[c16 c15 c14... c3 c2 c1] to store the Modbus CRC-16 check code;

D) define a loop counter (i) and let i=1;

E) Let crc=[crc([1:8])crc([9:16]).*m([1+(i-1)*8:i*8])], where “.*” stands for Multiply the positions of the two elements of the matrix:

F) Calculate c1=crc(9)*crc(10)*crc(11)*crc(12)*crc(13)*crc(14)**crc(15)*crc(16),c2=crc( 10) *crc(11)*crc(12)*crc(13)*crc(14)*crc(15)*crc(16),c3=crc(9)*crc(10),c4=crc(10) )*crc(11),c5=crc(11)*crc(12),c6=crc(12)*crc(13),c7=crc(13)*crc(14),c8=crc(14)* Crc(15),c9=crc(1)*crc(15)*crc(16),c10=crc(2)*crc(16),c11=crc(3),c12=crc(4),c13= Crc(5),c14=crc(6),c15=crc(7),c16=crc(8)*crc(9)*crc(10)*crc(11)*crc(12)*crc(13) *crc(14)**crc(15)*crc(16), where crc(k) is the value of the kth bit of the Modbus CRC-16 check code;

G) Check if the value of the loop counter (i) is less than d/8, and if so, increase the value of i by 1 (i=i+1) and return to step E). If not, proceed to the next step;

H) output the result of the calculation as a Modbus CRC-16 file;

I) Convert and sort the Modbus CRC-16 according to the rules of Modbus CRC-16 to get a hardware description language in Modbus CRC-16 format.

The Modbus CRC-16 check code generated by the Modbus CRC check code generating method proposed by the present invention can be directly written into the communication system of various facility controllers, so that the signal transmitted by the controller can pass through the generator at a time. The cycle is processed to improve the accuracy and reliability of the overall data transmission.

The technical means and efficacy of the present invention for achieving the object will be described below with reference to the accompanying drawings, and the embodiments listed in the following drawings are only for the purpose of explanation, and are to be understood by the reviewing committee, but the technical means of the present invention are not Limited to the listed figures.

Referring to FIG. 1 again, a flow chart of a Modbus CRC check code generation method includes the following steps: First, step 20 is performed to calculate the input data length (d), and the input data length (d) is divided by 8 to obtain a back. The number of times, wherein the input data length (d) is a minimum of 8 bits; in step 21, a data matrix m=[m(8*d) m(8*d-1) m(8*d-2) is defined. .. m(3) m(2) m(1)] is used to store the input data, where m(j) is the value of the jth bit of the input data; step 22, define a check code matrix crc=[c16 C15 c14... c3 c2 c1] is used to store the Modbus CRC-16 check code; step 23, define a loop counter (i), and let i=1; step 24, let crc=[crc([1:8 ])rcc([9:16]).*m([1+(i-1)*8:i*8])], where ".*" represents the multiplication of the two elements of the matrix: step 25, calculation C1=crc(9)*crc(10)*crc(11)*crc(12)*crc(13)*crc(14)**crc(15)*crc(16),c2=crc(10)* Crc(11)*crc(12)*crc(13)*crc(14)*crc(15)*crc(16),c3=crc(9)*crc(10),c4=crc(10)*crc (11), c5=crc(11)*crc(12), c6=crc(12)*crc(13), c7=crc(13)*crc(14),c8=crc(14)*crc(15 ), c9=crc(1)*crc(15)*crc(16),c10=crc(2)* Crc(16),c11=crc(3),c12=crc(4),c13=crc(5),c14=crc(6),c15=crc(7),c16=crc(8)*crc(9 ) *crc(10)*crc(11)*crc(12)*crc(13)*crc(14)**crc(15)*crc(16), where crc(k) is a Modbus CRC-16 test The value of the kth bit of the code; in step 26, it is checked whether the value of the loop counter (i) is less than d/8, and if so, the value of i is incremented by 1 (i=i+1), and returns to step 24 If not, proceed to the next step; in step 27, output the result of the calculation as a Modbus CRC-16 file; and in step 28, convert and sort the Modbus CRC-16 according to the rules of Modbus CRC-16. A hardware description language in Modbus CRC-16 format.

In step 29, the hardware description language of the Modbus CRC-16 format is written into a facility controller.

The hardware description language of the Modbus CRC-16 format can be written into the communication system of various facility controllers (such as nuclear energy level controllers) for use.

Referring again to Table 1, Table 1 is a Modbus CRC-16 check code operation method, where m is the variable storing the input data array, and m(j) is the value of the jth bit in the data array. Crc is the variable that stores the Modbus CRC-16 check code array, crc(k) is the value of the kth bit of the Modbus CRC-16 check code, i is the i-th circle, and d is the bit of the input data. The number is calculated from equation (1) to equation (17) as a loop.

Taking the data length as 32 bits as an example, the number of loops is 32 divided by 8 equals 4, and i is set to 1, the formula (1) is calculated, and the calculated result is stored in the corresponding register of the crc matrix, and then Calculate the formula (2) to (17) to obtain the value of each element ([c16 c15... c2 c1]) in the crc array, that is, complete the first loop, and then sequentially set i equal to 2, 3, 4 and repeat the calculation of the formula (1) to the formula (17).

Referring to FIG. 2, the Modbus CRC check code generation method is applied to the communication system diagram of the nuclear energy level controller. First, input any data length, and output a Modbus CRC-16 test after the Modbus CRC-16 check code program operation. Code, then convert the Modbus CRC-16 check code into a hardware description language format, and write it into a nuclear energy level control system. When a specific data bit is input to the nuclear energy level control system, a specific data bit can be output. And a specific Modbus CRC-16 check code.

However, the above description is only for the embodiments of the present invention, and the scope of the invention is not limited thereto. That is, the equivalent changes and modifications made in accordance with the claims of the present invention should still fall within the scope of the patent of the present invention. I would like to ask your review committee to give a clear understanding and pray for it.

20~28. . . flow chart

Figure 1 is a flow chart of the Modbus CRC check code generation method.

Figure 2 is a schematic diagram of the communication system of the Modbus CRC check code generation method applied to the nuclear energy level controller.

Claims (5)

A Modbus CRC check code generating method comprises the following steps: A) calculating the input data length (d), and dividing the input data length (d) by 8 to obtain a loop number, wherein the input data length (d) is minimum 8-bit; B) define a data matrix m=[m(8*d) m(8*d-1) m(8*d-2)...m(3) m(2) m(1) ] for storing input data, where m(j) is the value of the jth bit of the input data; C) defining a check code matrix crc=[c16 c15 c14...c3 c2 c1] for storing the Modbus CRC- 16 check code; D) define a loop counter (i) and let i=1; E) let crc=[crc([1:8])crc([9:16]).*m([1+ (i-1)*8:i*8])], where ".*" is multiplied by the position of the two elements of the matrix: F) Calculate c1=crc(9)*crc(10)*crc(11)*crc (12)*crc(13)*crc(14)*crc(15)*crc(16),c2=crc(10)*crc(11)*crc(12)*crc(13)*crc(14) *crc(15)*crc(16),c3=crc(9)*crc(10),c4=crc(10)*crc(11),c5=crc(11)*crc(12),c6=crc (12) *crc(13), c7=crc(13)*crc(14), c8=crc(14)*crc(15), c9=crc(1)*crc(15)*crc(16), C10=crc(2)*crc(16),c11=crc(3),c12=crc(4),c13=crc(5),c14=crc(6),c15=crc(7),c16=crc (8) *crc(9)*crc(10 )*crc(11)*crc(12)*crc(13)*crc(14)*crc(15)*crc(16), where crc(k) is Modbus CRC-16 Check the value of the kth bit of the check code; G) Check if the value of the loop counter (i) is less than d/8, and if so, increase the value of i by 1 (i=i+1) and return to step E. ), if no, proceed to the next step; H) output the result of the calculation as a Modbus CRC-16 file. A method for generating a Modbus CRC check code according to claim 1, wherein after step H), there is further included a step I) converting and sorting the Modbus CRC-16 according to the rules of Modbus CRC-16. Get a hardware description language in Modbus CRC-16 format. A method for generating a Modbus CRC check code according to claim 2, wherein after step H), there is further included a step J) writing the hardware description language of the Modbus CRC-16 format into a facility controller. A method for generating a Modbus CRC check code according to claim 3, wherein the facility controller is a nuclear energy level controller. A method for generating a Modbus CRC check code according to claim 3, wherein the facility controller is a communication system of a nuclear energy level controller.