Modbus protocol display |modbus Communication display |modbus display electronic screen function code sharing

Modbus protocol display |modbus Communication display |modbus display electronic screen function code sharing, mainly used to achieve "preset multiple register function code."

The "0X1F" function code of the MODBUS-RTU protocol is photographed as follows:

An example of the "0X1F" function code for the MODBUS-RTU protocol is as follows:

Example: The request is placed in 2 registers from the Modbus display device 17, the starting register is 40002, the preset value is 0AH and 02H.
QUERY
Field Name
Slave Address
Function
Starting Address Hi
Starting Address Lo
No. of registers Hi
No. of registers Lo
Byte Count
Data Hi
Data Lo
Data Hi
Data Lo
Error Check (LRC or CRC)

Example
(Hex)
11
10
00
01
00
02
04
00
0A
01
02
—
Preset multiple Registers

void Isr_usart1 (void) {
unsigned int crc=0,i=0;
unsigned char x=0;
Nx,ny correction
if (nx==0) {
x=4;
}else{
X=nx-1;
}
Industrial Modbus Display parameter processing
if (rxdata[0]==ip_num[x][0]&&rxdata[1]==0x03) {
CRC=CRC16 (rxdata,5);
if (crc== (rxdata[6]<<8) +rxdata[5]) {
Verify that the correct receive processing data enters
modbus_num[x][0]= (rxdata[3]<<8) +rxdata[4];
}
}
Modbus Communication Time parameter processing
if (rxdata[0]==0x55&&rxdata[1]==0x03) {
CRC=CRC16 (rxdata,19);
if (crc== (rxdata[20]<<8) +rxdata[19]) {
Verify that the correct receive processing data enters
for (i=0;i<8;i++) {
Time_buf[i]=rxdata[4+2*i];
}
for (i=0;i<7;i++) {
time_num[0+2*i]=time_buf[i]>>4;
time_num[1+2*i]=time_buf[i]&0x0f;
}
}
}
}

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Modbus protocol Display |modbus Communication display |modbus display electronic screen function code to realize the codeshare