RS232 Communication problem

Hi. I'm using Arduino Uno.
I wanna acquire the F/T sensor data.
So I made a code for RS232.
But It doesn't work.
Help me please.
Below is my code and I attach a datasheet of F/T Sensor.

#include <SoftwareSerial.h>
#define TxBufferSize 11
#define RxBufferSize 19

SoftwareSerial FT_Sensor_Serial(A4, A5);//시리얼 통신 핀 A4 : Rx, A5 : Tx

//Variable
unsigned char TxBuffer[11];
unsigned char RxBuffer[19];

int data = 0;
int command = 0;

//Funtion
void FT_Sensor_Tx(void);
unsigned char Checksum(unsigned char *buff, int size);

void setup(){
  Serial.begin(115200);
  FT_Sensor_Serial.begin(115200);
}

void loop(){
  //Tx, Rx 버퍼 초기화
  for(int i = 0; i < TxBufferSize; i++)
    TxBuffer[i] = 0;
  for(int i = 0; i < RxBufferSize; i++)
    RxBuffer[i] = 0;
  
  //Set the SOP and EOP of TxBuffer value
  TxBuffer[0] = 0x55; //SOP, start bit
  TxBuffer[10] = 0xAA; //EOP, end bit
  
  Serial.println("Please set the command of TxBuffer data field");
  while(!(command)) command = Serial.parseInt(); //Tx until setting the command value(command가 0이 아닐때까지 무한루프)
  
  FT_Sensor_Tx(); //Tx data 설정
  
  TxBuffer[9] = Checksum(TxBuffer, TxBufferSize); //Checksum

  for(int i = 0; i < TxBufferSize; i++){ //F/T 센서로 Tx값 보냄
    FT_Sensor_Serial.println(TxBuffer[i]); 
    Serial.print("TxBuffer[");
    Serial.print(i);
    Serial.print("] : ");
    Serial.println(TxBuffer[i]);
  }
  
  delay(1000);
  
  if(FT_Sensor_Serial.available()){
    Serial.println("Communication success");
   
    FT_Sensor_Serial.readBytes(RxBuffer, 19);
    
    for(int i = 2; i < (RxBufferSize - 2); i++){//읽은 데이터 출력
      data = atoi(RxBuffer[i]); //ASCII를 Int형으로 변환
      Serial.print(i);
      Serial.print(" : ");
      Serial.println(data);
    }
    
    delay(1000);
  }
}

void FT_Sensor_Tx(void)
{
  //Set the TxBuffer data field value
  Serial.println("=================== F/T Sensor TxBuffer ===================");
  switch(command){
    case 1: //Read Model Name
      Serial.println("Command 1 : Read Model Name");
      TxBuffer[1] = 0x01;
      break;
    case 2: //Read Serial Nmber
      Serial.println("Command 2 : Read Serial Nmber");
      TxBuffer[1] = 0x02;
      break;
    case 3: //Read Firmawrae Version
      Serial.println("Command 3 : Read Firmawrae Version");
      TxBuffer[1] = 0x03;
      break;    
    case 4: //Set Commnunication ID(CAN only)
      Serial.println("No valid!! Command 4 : Set Commnunication ID(CAN only)");
      break;
    case 5: //Read Communication ID(CAN only)
      Serial.println("No valid!! Command 5 : Read Communication ID(CAN only)");
      break;
    case 6: //Set Baud-rate(UART only)
      Serial.println("Command 6 : Set Baud-rate(UART only)");
      TxBuffer[1] = 0x06;
      TxBuffer[2] = 0x00; //Baud-rate : 115,200
      
      if(TxBuffer[2] == 0x00)
        Serial.println("Baud-rate : 115,200");
      else if(TxBuffer[2] == 0x01)
        Serial.println("Baud-rate : 921,600");
      else if(TxBuffer[2] == 0x02)
        Serial.println("Baud-rate : 460,800");
      else if(TxBuffer[2] == 0x03)
        Serial.println("Baud-rate : 230,400");
      else if(TxBuffer[2] == 0x04)
        Serial.println("Baud-rate : 115,200");
      else
        Serial.println("Baud-rate : 57,600");
      break;
    case 7: //Read Baud-rate
      Serial.println("Command 7 : Read Baud-rate");
      TxBuffer[1] = 0x07;
      break;
    case 8: //Set Filter (0 : No filter, 1 : 1st order low-pass filter)
      Serial.println("Command 8 : Set Filter");
      TxBuffer[1] = 0x08;
      TxBuffer[2] = 0x00; //Filter Type, No filter
      TxBuffer[3] = 0x00; //Filter Parameter(Hz), No filter

      if((TxBuffer[2] == 0x00 || TxBuffer[2] == 0x01) && TxBuffer[3] == 0x00)
        Serial.println("Filter Type : No filter, Filter Parameter : No filter");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x01)
        Serial.println("Filter Type : 1, Filter Parameter : 1, Cutoff Frequency : 500Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x02)
        Serial.println("Filter Type : 1, Filter Parameter : 2, Cutoff Frequency : 300Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x03)
        Serial.println("Filter Type : 1, Filter Parameter : 3, Cutoff Frequency : 200Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x04)
        Serial.println("Filter Type : 1, Filter Parameter : 4, Cutoff Frequency : 150Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x05)
        Serial.println("Filter Type : 1, Filter Parameter : 5, Cutoff Frequency : 100Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x06)
        Serial.println("Filter Type : 1, Filter Parameter : 6, Cutoff Frequency : 50Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x07)
        Serial.println("Filter Type : 1, Filter Parameter : 7, Cutoff Frequency : 40Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x08)
        Serial.println("Filter Type : 1, Filter Parameter : 8, Cutoff Frequency : 30Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x09)
        Serial.println("Filter Type : 1, Filter Parameter : 9, Cutoff Frequency : 20Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x0A)
        Serial.println("Filter Type : 1, Filter Parameter : 10, Cutoff Frequency : 10Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x0B)
        Serial.println("Filter Type : 1, Filter Parameter : 11, Cutoff Frequency : 5Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x0C)
        Serial.println("Filter Type : 1, Filter Parameter : 12, Cutoff Frequency : 3Hz");
      else if(TxBuffer[2] == 0x01 && TxBuffer[3] == 0x0D)
        Serial.println("Filter Type : 1, Filter Parameter : 13, Cutoff Frequency : 2Hz");
      else
        Serial.println("Filter Type : 1, Filter Parameter : 14, Cutoff Frequency : 1Hz");
      break;
    case 9: //Read Filter Setting
      Serial.println("Command 9 : Read Filter Setting");
      TxBuffer[1] = 0x09;
      break;
    case 10: //Read F/T data (once)
      Serial.println("Command 10 : Read F/T data (once)");
      TxBuffer[1] = 0x10;
      break;
    case 11: //Start F/T Data Output
      Serial.println("Command 11 : Start F/T Data Output");
      TxBuffer[1] = 0x11;
      break;
    case 12: //Stop F/T Data Output(Available even during data output)
      Serial.println("Command 12 : Stop F/T Data Output(Available even during data output)");
      TxBuffer[1] = 0x12;
      break;
    case 13: //Reserved
      Serial.println("Command 13 : Reserved");
      break;
    case 14: //Reserved
      Serial.println("Command 14 : Reserved");
      break;
    case 15: //Set Data Output Rate
      Serial.println("Command 15 : Set Data Output Rate");
      TxBuffer[1] = 0x0F;
      TxBuffer[2] = 0x00; //Default : 0[200Hz], Refer to Section 3.6.16 Allowable Data Ouput Rate in datasheet
      
      if(TxBuffer[2] == 0x00)
        Serial.println("Default : 0[200Hz]");
      else if(TxBuffer[2] == 0x01)
        Serial.println("Default : 1[10Hz]");
      else if(TxBuffer[2] == 0x02)
        Serial.println("Default : 2[20Hz]");
      else if(TxBuffer[2] == 0x03)
        Serial.println("Default : 3[50Hz]");
      else if(TxBuffer[2] == 0x04)
        Serial.println("Default : 4[100Hz]");
      else if(TxBuffer[2] == 0x05)
        Serial.println("Default : 5[200Hz]");
      else if(TxBuffer[2] == 0x06)
        Serial.println("Default : 6[333Hz]");
      else if(TxBuffer[2] == 0x07)
        Serial.println("Default : 7[500Hz]");
      else
        Serial.println("Default : 8[1000Hz]");  
      break;
    case 16: //Read Data Output Rate(Available even during data output)
      Serial.println("Command 16 : Read Data Output Rate(Available even during data output)");
      TxBuffer[1] = 0x10;
      break;
    case 17: //Set Bias
      Serial.println("Command 17 : Set Bias");
      TxBuffer[1] = 0x11;
      TxBuffer[2] = 0x00; //Bias parameter 0(0x00) : un-bias, Bias parameter 1(0x01) : set-bias
      
      if(TxBuffer[2] == 0x00)
        Serial.println("Bias parameter : 0(un-bias)");
      else
        Serial.println("Bias parameter : 1(set-bias)");
      break;
    case 18: //Read Count of Overload Occurrence
      Serial.println("Command 18 : Read Count of Overload Occurrence");
      TxBuffer[1] = 0x12;
      break;
    default:
      Serial.println("The command value is invalid");
      break;
    }//switch(command)
  Serial.println("===========================================================");
}

unsigned char Checksum(unsigned char *buff, int size)
{
  unsigned char m_checksum = 0;

  for(int i = 1; i < (size - 2); i++)
    m_checksum += buff[i];

  return m_checksum;
}

I think you will have problems running a software serial port at 115200 on an UNO. From what I've read, software serial works reliably up to 19200 baud.

A Uno requires an adapter board to convert RS-232 signals to the 0-5 volt signals that can be read by the Arduino. You did not mention that you are using such a board.

Paul