dnp3 rtu

With the rapid development of the Internet of Things, wireless network communication technology has reached a historical height, but in the face of more and more open network environment, data transmission security is more and more challenging. Due to hacking or interception of data and other reasons, it is very easy to have data loss leakage, resulting in significant consequences will be very large, through the application of secure transmission technology, to a large extent, can effectively pr

distance.(3) RS485 interface using a combination of balanced driver and differential receiver, anti-common mode interference ability, that is, anti-noise interference is good, so the communication distance, the maximum transmission distance of about 1200m, the actual up to 3000m.(4) The RS485 interface allows the connection of up to 128 transceivers on the bus, with a multi-station capability. At the same time, two terminal resistors are required, and their resistance is equal to the characteri

Modbus is a good serial communication protocol, in which RTU protocol is most commonly used, through the Modbus RTU, we can easily read and write serial information.Download Libmodbus from official website and observe modbus.h that the key structure is:typedef struct {int nb_bits;int nb_input_bits;int nb_input_registers;int nb_registers;uint8_t *tab_bits;uint8_t *tab_input_bits;uint16_t *tab_input_registers

40001Because it belongs to the 4X register, while the 0X register is starting from 00001, the 1X register starts from 10001 and the rest is identical.(B), in fact, 40001 corresponds to the No. 0 address cell of the buffer in your program,If: Your program defines a buffer (20) to exchange data with the host computer 40001-40020, then40001----> BUFFER (0)40002----> BUFFER (1)40003----> BUFFER (2)40004----> BUFFER (3)........................40020----> BUFFER (19) =============================

Tags: style technology includes strong over message send bytes remote terminal complete1. RTU modeWhen the controller is set to communicate in RTU (remote terminal Unit) mode on the Modbus network, each 8Bit byte in the message contains twoA hexadecimal character of 4Bit. The main advantage of this approach is that, at the same baud rate, more than the ASCII method can transmit moreData.Code system· 8-bit b

interface appears.Click on the "Add Device" button and the "Add Device" screen appears. As shown in the following:Set the user ID and device ID that were consistent with the previous device. The user ID is set to 00000000, and the device ID is set to FFFFFFFF. As shown in the following:Click Confirm to complete the setup and close the registration management interface.Server parameter settingsCreate a new two TCP server receive centerThe server type is set to: TCPLocal ports are set to: 30039,

The CRC is calculated using only 8 data bits, starting bit and stop bit, if parity bit also includes parity bit , do not participate in CRC calculation.The CRC is calculated by:1. Load a 16-bit register with a value of 0XFFFF, which is the CRC register.2, the first 8-bit binary data (that is, the first byte of the communication information frame) and the 16-bit CRC register is different or, the result is still stored in the CRC register.3, the CRC register the contents of the right one bit, with

, 0x5A, 0x9a, 0x9b, 0x5b, 0x99, 0x59, 0x58, 0x98,0x88, 0x48, 0x49, 0x89, 0x4B, 0x8b, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4f, 0x8d, 0x4d, 0x4C, 0x8c,0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83, 0x41, 0x81, 0x80, 0x40};unsigned short Uicrchi;unsigned short uicrclo;unsigned short uiindex;Uicrchi = 0xFF;Uicrclo = 0xFF;Uiindex = 0;CRC operationwhile (uicrcdatalen--){Uiindex = Uicrchi ^ *p_uidata++;Uiindex = 0xFF;Uicrchi = Uicrclo ^ C_uicrchigh[uiindex];Uicrchi = 0xFF;Uicrclo =

Cai Mao CM550 Series Intelligent Wireless Remote Control Terminal (hereinafter referred to as wireless RTU), in order to meet the market demand and self-developed collection of data acquisition, long-range and wireless communication functions as one of the wireless terminal control products. RTU integrates analog signal acquisition, switching volume input, switching output, pulse count, support Ethernet com

(a), communication mode of transmission :Communication transmission is divided into independent information headers, and transmitted encoded data. The following communication mode definitions are also compatible with the Modbus RTU Communication protocol: compilation Code 8 bits Binary Starting bit 1 guests Data bits 8 Guests Parity bit 1-bit (even parity bit)

Label:An RTU transmits a higher density than the ASCII. Parameter format: Start bit +8bits data bit + check digit + stop bit.1.1 Check default is parity, recommended for no verification, test to more than one stop bit (that is, stop bit is 2 bits)1.2 Send order from left to right LSB->MSB1.3 must be satisfied when the communication rate is less than or equal to 19200: the interval between frames is not less than 3.5 character time and the interval bet