How to transmit data using RS485 with uart?

[MÇETİ.1]

Hi everyone,

I'm trying to transmit and receive data through rs485 with uart. Using Uart with DMA in normal mode and referance from this project.

https://controllerstech.com/rs485-module-and-stm32/

However, in this project there are 2 different stm. I want to use 1 stm 2 uarts and 2 module. Therefore I combine these two codes. It writes SEND to tx buffer but neither transmit nor receive. When I check serial port to see data, only 00 or null

void dataSend (uint8_t *data)
{
           if(huart.Instance == UART1)
      {           
		HAL_GPIO_WritePin(UART1_EN_GPIO_Port, UART1_EN_Pin, 1);
		HAL_UART_Transmit_DMA(&huart1, (uint8_t*)rx1_buffer, rx_buff);
		HAL_GPIO_WritePin(UART1_EN_GPIO_Port, UART1_EN_Pin, 0);
 
       }
        else if(huart.Instance == UART2)
       {
		HAL_GPIO_WritePin(UART2_EN_GPIO_Port, UART2_EN_Pin, 1);
		HAL_UART_Transmit(&huart2, rx2_buffer, sizeof(rx_buff),1000);
		HAL_GPIO_WritePin(UART2_EN_GPIO_Port, UART2_EN_Pin, 0);
          }
 
}
void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size)
{
	if(huart->Instance == USART1)
	{
	  HAL_UARTEx_ReceiveToIdle_DMA(&huart1, rx1_buffer, rx_buff);
 
	}
	else if(huart->Instance == USART2)
	{
			rx3_buffer[0] = "F";
			rx3_buffer[1] = "P";
			rx3_buffer[2] = "G";
			rx3_buffer[3] = "A";
 
			dataSend(rx2_buffer);
			HAL_UARTEx_ReceiveToIdle_DMA(&huart2, rx2_buffer, rx_buff);
 
	}
}
 
 
int main()
{
 
  HAL_UARTEx_ReceiveToIdle_DMA(&huart1, rx1_buffer, rx_buff);
  HAL_Delay(100);
  HAL_UARTEx_ReceiveToIdle_DMA(&huart2, rx2_buffer, rx_buff);
 
 
 
 
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
	  sprintf(tx1_buffer, "SEND %d",indx++);
	  dataSend(tx1_buffer);
	  HAL_Delay(100);
  }
}