基于MODBUS协议的读取寄存器内容的C++实现

最新推荐文章于 2025-06-20 08:50:09 发布

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#MODBUS #读取寄存器 #C++ 实现

本文介绍了一种基于MODBUS协议的C++实现方法，用于读取不同类型寄存器的内容，包括线圈状态、离散输入状态、保持寄存器和输入寄存器。通过示例代码展示了如何使用MODBUS_RTU进行设备通信，读取指定地址的数据，并将结果写入Excel文件。

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基于MODBUS协议的读取寄存器内容的C++实现

#ifndef _MSC_VER
#include <unistd.h>
#endif 

#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include "modbus.h"
#include<stdio.h>
#include <iostream>
#include <fstream>
#include <streambuf>
using namespace std;
void write_to_excel(string filename, bool&flag,int nb,int addr,int *p)
{	
	//定义文件输出流   
	ofstream oFile;

	//打开要输出的文件   
	oFile.open(filename, ios::out | ios::trunc);   
	oFile << "地址" << "\t" << "值" << endl;
	for (int i = 0; i < nb; i++, addr++,p++) {
		oFile << addr << "\t" << *p << endl;
	}
	
	

	oFile.close();
}//线圈状态
int * read_0x(modbus_t *ctx,int addr,int nb) {
	uint8_t *tab_rp_bits;
	int ADDRESS_END;
	int rc;;
	int *p = new int[nb];
	tab_rp_bits = (uint8_t *)malloc((nb+1)* sizeof(uint8_t));
	memset(tab_rp_bits, 0, (nb+1) * sizeof(uint8_t));
	ADDRESS_END = addr + nb;
	
		rc = modbus_read_bits(ctx, addr, nb, tab_rp_bits);
		if (rc != nb )
		{
			printf("error modbus_read_bits single (%d) \n", rc);
			printf("address =%d\n", addr);
		
		}
		else {
			for (int i = 0; i <nb; i++,addr++) {
				
				printf("addr=%d,value=%d\n", addr, tab_rp_bits[i]);
				p[i] = tab_rp_bits[i];
			}
		}
		//free(tab_rp_bits);
		return p;
}
//离散输入状态
int * read_1x(modbus_t *ctx, int addr, int nb) {
	uint8_t *tab_rp_bits;
	int ADDRESS_END;
	int rc;
	int *p = new int[nb];
	tab_rp_bits = (uint8_t *)malloc((nb + 1) * sizeof(uint8_t));
	memset(tab_rp_bits, 0, (nb + 1) * sizeof(uint8_t));
	ADDRESS_END = addr + nb;

	rc = modbus_read_input_bits(ctx, addr, nb, tab_rp_bits);
	if (rc != nb)
	{
		printf("error modbus_read_bits single (%d) \n", rc);
		printf("address =%d\n", addr);

	}
	else {
		for (int i = 0; i < nb; i++, addr++) {
			printf("addr=%d,value=%d\n", addr, tab_rp_bits[i]);
			p[i] = tab_rp_bits[i];
		}
	}
	//free(tab_rp_bits);
	return p;
}
//保持寄存器
int * read_2x(modbus_t *ctx, int addr, int nb) {
	uint16_t *tab_rp_bits;
	int ADDRESS_END;
	int rc;
	int *p = new int[nb];
	tab_rp_bits = (uint16_t *)malloc((nb + 1) * sizeof(uint16_t));
	memset(tab_rp_bits, 0, (nb + 1) * sizeof(uint16_t));
	ADDRESS_END = addr + nb;

	rc = modbus_read_registers(ctx, addr, nb, tab_rp_bits);
	if (rc != nb)
	{
		printf("error modbus_read_bits single (%d) \n", rc);
		printf("address =%d\n", addr);

	}
	else {
		for (int i = 0; i < nb; i++, addr++) {
			uint16_t n = tab_rp_bits[i] & 0x8000;
			if (n == 0x8000) {
				tab_rp_bits[i] = ~(tab_rp_bits[i]) + 1;
				p[i] = tab_rp_bits[i] * (-1);
				printf("addr=%d,value=-%d\n", addr, tab_rp_bits[i]);

			}
			else {
				p[i] = tab_rp_bits[i];
				printf("addr=%d,value=%d\n", addr, tab_rp_bits[i]);

			}
		}
	}
	//free(tab_rp_bits);
	return p;
}
//输入寄存器
int * read_3x(modbus_t *ctx, int addr, int nb) {
	uint16_t *tab_rp_bits;
	int ADDRESS_END;
	int rc;
	int *p = new int[nb];
	tab_rp_bits = (uint16_t *)malloc((nb + 1) * sizeof(uint16_t));
	memset(tab_rp_bits, 0, (nb + 1) * sizeof(uint16_t));
	ADDRESS_END = addr + nb;

	rc = modbus_read_input_registers(ctx, addr, nb, tab_rp_bits);
	if (rc != nb)
	{
		printf("error modbus_read_bits single (%d) \n", rc);
		printf("address =%d\n", addr);

	}
	else {
		for (int i = 0; i < nb; i++, addr++) {
			uint16_t n = tab_rp_bits[i] & 0x8000;
			if (n == 0x8000) {
				tab_rp_bits[i] = ~(tab_rp_bits[i])+1;
				p[i] = tab_rp_bits[i]*(-1);
				printf("addr=%d,value=-%d\n", addr, tab_rp_bits[i]);
			}
			else {
				printf("addr=%d,value=%d\n", addr, tab_rp_bits[i]);
				p[i] = tab_rp_bits[i];
			}
			
		}
	}
	//free(tab_rp_bits);
	return p;
}

int main() {
	modbus_t *ctx;
	int ID;
	int ADDRESS_START;
	int nb;
	int reg;
	bool flag = false; 
	
	
	cout << "要查看那类寄存器?\n线圈状态 1\n离散输入状态 2\n保持寄存器 3\n输入寄存器 4\n";
	cin >> reg;
	cout << "ID:";
	cin >> ID;
	cout << "起始地址:";
	cin >> ADDRESS_START;
	cout << "地址数量:";
	cin >> nb;
	ctx = modbus_new_rtu("COM3", 19200, 'N', 8, 1);
	int *p=new int[nb];
	modbus_set_slave(ctx, ID);
	modbus_set_debug(ctx, TRUE);
	if (modbus_connect(ctx) == -1) {
		fprintf(stderr, "Connection failed:%s\n", modbus_strerror(errno));
		modbus_free(ctx);
		return -1;
	}
	switch (reg)
	{
		case 1:{
			p=read_0x(ctx, ADDRESS_START, nb);
			break;
		}
		case 2: {
			p=read_1x(ctx, ADDRESS_START, nb);
			break;
		}
		case 3: {
			p=read_2x(ctx, ADDRESS_START, nb);
			break;
		}
		case 4: {
			p=read_3x(ctx, ADDRESS_START, nb);
			break;
		}
	}
	/*for (int j = 0; j < 8; j++,p++) {
		printf("%d\t%d", j, *p);
	}*/
	write_to_excel("C:\\Users\\DELL\\Desktop\\test.xls", flag,nb, ADDRESS_START,p);
	delete[] p;
	modbus_close(ctx);
	modbus_free(ctx);
	return 0;
}