树莓派串口利用modbus通信

1、安装

sudo apt-get install libmodbus-dev

2、搭建modbus环境

https://blog.csdn.net/starelegant/article/details/72782946

3、编写测试程序

https://blog.csdn.net/qq_23670601/article/details/82155378#%E5%88%9D%E8%AF%95%E5%8C%96RTU%E7%8E%AF%E5%A2%83%E6%8C%87%E9%92%88%20modbus_t%20*modbus_new_rtu(const%20char%20*device%2C%20int%20baud%2C%20char%20parity%2C%20int%20data_bit%2C%20int%20stop_bit)

#include 
#include 
#include 

int main()
{
  modbus_t *mb;
  uint16_t tab_reg[32]={0};
  mb=modbus_new_rtu("/dev/ttyS0",115200,'N',8,1);
  if(0==modbus_rtu_get_serial_mode(mb))
  {
     modbus_rtu_set_serial_mode(mb,MODBUS_RTU_RS232);
     printf("serial is RS232\n");
  }
  else {
     printf("serial is RS485\n");
     modbus_rtu_set_serial_mode(mb,MODBUS_RTU_RS485);
  }
  modbus_set_slave(mb,1);
//  modbus_rtu_set_rts(mb,MODBUS_RTU_RTS_UP);
  modbus_connect(mb);
  int regs=modbus_read_registers(mb,0,8,tab_reg);
  printf("%d %d %d %d %d\n",regs,tab_reg[0],tab_reg[1],tab_reg[2],tab_reg[3]);

  modbus_close(mb);
  modbus_free(mb);
  return 0;
}

4、gcc modbus_rtu.c -o modbus_rtu -lmodbus

如果用了wiringPi库，还要加上-lwiringPi

5、测试