嵌入式开源库之libmodbus学习笔记

socat 安装sudo apt-get install socat创建终端 socat -d -d pty,b115200 pty,b115200查看终端 ls /dev/pts/ minicom 安装 sudo apt-get install minicom链接虚拟终端 sudo minicom -D /dev/pts/3以十六进制显示 minicom -D /dev/pts/1 -H设置波特率 minicom -D /dev/pts/1 -b B115200设置回显 Ctrl+A->Z->E设置自动换行 Ctrl+A->W清屏 Ctrl+A->C退出 Ctrl+A->X 交叉编译 生成配置文件./autogen.sh配置./configure --host=arm-linux-gnueabihf --prefix=$(pwd)/__install编译 make(如果遇到C++版本问题请升级交叉编译器)安装 make install查看生成的库文件类型file libmodbus.so.5.1.0 libmodbus.so.5.1.0: ELF 32-bit LSB shared object, ARM, EABI5 version 1 (SYSV), dynamically linked, BuildID[sha1]=d30e9af8a0ccc675f8549abbfa88e8df5574b196, with debug_info, not stripped 将库文件放到开发板的库文件目录下 cd /usr/lib mv /root/libmodbus.so.5.1.0 ./创建软连接 ln -s libmodbus.so.5.1.0 libmodbus.so.5

./libmodbus.exe: /lib/libstdc++.so.6: version `GLIBCXX_3.4.21’ not found (required by ./libmodbus.exe)

Ubuntu编译

/usr/bin/ld: 找不到 -lmodbus collect2: error: ld returned 1 exit status

./a.out: error while loading shared libraries: libmodbus.so.5: cannot open shared object file: No such file or directory

将库文件的路径添加到 /etc/ld.so.conf 文件中，并运行 sudo ldconfig 命令来更新库缓存。例如，如果库文件位于 /home/lux/OpenSource/libmodbus/__install/lib 目录中，您可以将以下行添加到 /etc/ld.so.conf 文件的末尾： /home/lux/OpenSource/libmodbus/__install/lib 保存文件后，运行 sudo ldconfig 命令。

测试 tcp_client #include "modbus_tcp.hpp" #include <unistd.h> int main(int argc, char *argv[]) { uint8_t read_buffer[1024]; uint8_t write_buffer[1024]; uint16_t read_buffer_16[3]; uint16_t write_buffer_16[1024]; uint8_t ret = 0; modbus::modbus_tcp modbus("192.168.2.200",60000); //创建一个modbus_tcp对象 for (int i = 0; i < 10; i++) { ret = modbus.read_coil_status(0x0000, 5, read_buffer);//00 01 00 00 00 06 01 01 67 89 00 05 if (ret > 0) { printf("read_coil_status:%d\r\n",ret); for (int j = 0; j < ret; j++) { printf("%02x ",read_buffer[j]); } printf("\r\n"); } usleep(1000*100); ret = modbus.read_input_status(0x0000, 5, read_buffer);//00 01 00 00 00 06 01 01 67 89 00 05 if (ret > 0) { printf("read_input_status:%d\r\n",ret); for (int j = 0; j < ret; j++) { printf("%02x ",read_buffer[j]); } printf("\r\n"); } usleep(1000*100); ret = modbus.read_holding_register(0x0000, 5, read_buffer_16);//00 01 00 00 00 06 01 01 67 89 00 05 if (ret > 0) { printf("read_holding_register:%d\r\n",ret); for (int j = 0; j < ret; j++) { printf("%02x ",read_buffer_16[j]); } printf("\r\n"); } usleep(1000*100); ret = modbus.read_input_register(0x0000, 5, read_buffer_16);//00 01 00 00 00 06 01 04 67 89 00 05 if (ret > 0) { printf("read_input_register:%d\r\n",ret); for (int j = 0; j < ret; j++) { printf("%02x ",read_buffer_16[j]); } printf("\r\n"); } usleep(1000*100); // printf("write_single_coil:%d\r\n",modbus.write_single_coil(0x0000, 0x1234)); // usleep(1000*100); // printf("write_single_register:%d\r\n",modbus.write_single_register(0x0000, 0x1234));//0x06：写单个保持寄存器: 00 01 00 00 00 06 01 06 67 89 12 34 // usleep(1000*100); // printf("write_multiple_coil:%d\r\n",modbus.write_multiple_coil(0x0000, 5, write_buffer));//0x0F（15）：写多个线圈: 00 01 00 00 00 08 01 0F 67 89 00 05 01 1F // usleep(1000*100); // printf("write_multiple_registers:%d\r\n",modbus.write_multiple_registers(0x0000, 5, write_buffer_16));//0x10（16）：写多个保持寄存器: 00 01 00 00 00 11 01 10 67 89 00 05 0A 00 00 00 00 00 00 00 00 00 05 // usleep(1000*100); } usleep(1000*500); } modbus_slave