Qt RTU :使用Modbus C++类(RS485)从多个从机读取数据

QT += core
QT -= gui

CONFIG += c++11

TARGET = ModbusRTUReader
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

# 添加libmodbus库
LIBS += -lmodbus

#include <QCoreApplication>
#include <iostream>
#include <libmodbus/modbus.h>

void readFromSlave(modbus_t *ctx, int slaveId, uint16_t startAddress, int count) {
    uint16_t tab_reg[32]; // 假设我们最多读取32个寄存器
    int rc;

    // 设置从机ID
    modbus_set_slave(ctx, slaveId);

    // 读取保持寄存器
    rc = modbus_read_registers(ctx, startAddress, count, tab_reg);
    if (rc == -1) {
        std::cerr << "ERROR reading registers from slave " << slaveId << ": " << modbus_strerror(errno) << std::endl;
        return;
    }

    // 打印读取的数据
    std::cout << "Data from slave " << slaveId << ":" << std::endl;
    for (int i = 0; i < rc; ++i) {
        std::cout << "Register " << startAddress + i << ": " << tab_reg[i] << std::endl;
    }
}

int main(int argc, char *argv[]) {
    QCoreApplication a(argc, argv);

    // 创建Modbus上下文
    modbus_t *ctx = modbus_new_rtu("/dev/ttyUSB0", 9600, 'N', 8, 1);
    if (ctx == nullptr) {
        std::cerr << "Unable to allocate libmodbus context" << std::endl;
        return -1;
    }

    // 设置RTU模式
    modbus_set_mode(ctx, MODBUS_RTU);

    // 从多个从机读取数据
    readFromSlave(ctx, 1, 0, 10);  // 从从机1读取地址0开始的10个寄存器
    readFromSlave(ctx, 2, 0, 10);  // 从从机2读取地址0开始的10个寄存器

    // 释放Modbus上下文
    modbus_free(ctx);

    return a.exec();
}

qmake
make
./ModbusRTUReader