Knowledge Base Nr: 00231 modbustcp.cpp - http://www.swe-kaiser.de

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Linux: Modbus/TCP mit FieldTalk Master Protocol Pack-Toolkit gekapselt in C++-Klasse

  
//http://www.focus-sw.com
//lib für linux und win32

extern "C"
{
  int MBConnect(const char* lpszHostIP);
  int MBDisconnect();
  int MBRead(int nAddr);
  int MBWrite(int nAddr, int nValue);
  int MBZeroAll(int nMaxWords);
  int MBSetBit(int nDIOBitNo, int nValue);
  int MBGetFirstBit(int nMaxWords);
}

class CModBusTCP
{
public:
  CModBusTCP();
  virtual ~CModBusTCP();

  int Connect(const char* lpszHostIP);
  int Disconnect();

  int Read(int nAddr, short* nValue, int nWordCount);
  int Write(int nAddr, short* pnValue, int nWordCount);

protected:

private:
  MbusTcpMasterProtocol m_mbusProtocol;
};


////////////////////////////
//sample

int main()
{
  CModBusTCP mb;

  signal(SIGINT, Exithandler);

  int nErr = 0;
  const char* lpszConnect = "153.95.169.235";

  nErr = mb.Connect(lpszConnect);
LOG("MAIN: Connect(%s) nErr=%d", lpszConnect, nErr);

  for (int n=0; n<256; n++)
  {
    int nAddrRead = 1;
    int nAddrWrite = 1;
    short nValue = 0;
    int nWordCount = 1;


    nErr = mb.Read(nAddrRead, &nValue, nWordCount);
LOG("MAIN: Read(%d, %p, %d) : nErr=%d => val: 0x%04X", nAddrRead, &nValue, nWordCount, nErr, nValue);

    nValue = n;
    nErr = mb.Write(nAddrWrite, &nValue, nWordCount);
LOG("MAIN: Write(%d, %d) : nErr=%d", nAddrWrite, &nValue, nErr);

    usleep(DELAY_MS*1000);  //us
  }

  nErr = mb.Disconnect();
LOG("MAIN: Disconnect() nErr=%d", nErr);

LOG("MAIN: return=%d\n", nErr);

  return nErr;
}

///////////////////////////////////////
//cpp interface

static void sig_alarm_handler(int sig_nr);
static jmp_buf g_progzust_timeout;

int CModBusTCP::Connect(const char* lpszHostIP)
{
  TRACE("CModBusTCP::Connect(%s)", lpszHostIP);

  int nTimeout = 500;
  int nRetry = 0;
  int nDelay = 0;

  m_mbusProtocol.setTimeout(nTimeout);
  m_mbusProtocol.setRetryCnt(nRetry);
  m_mbusProtocol.setPollDelay(nDelay);

  int nResult = m_mbusProtocol.openProtocol(lpszHostIP);
  if (nResult != FTALK_SUCCESS)
  {
    TRACE("ERROR: openProtocol(%s)!", getBusProtocolErrorText(nResult));
    return -1;
  }

  nTimeout = m_mbusProtocol.getTimeout();
  nRetry = m_mbusProtocol.getRetryCnt();
  nDelay = m_mbusProtocol.getPollDelay();
  LOG("INFO: getTimeout:%d getRetryCnt:%d getPollDelay:%d!", nTimeout, nRetry, nDelay);

  return 0;
}

int CModBusTCP::Disconnect()
{
  TRACE("CModBusTCP::Disconnect()");

  m_mbusProtocol.closeProtocol();

  return 0;
}

static void sig_alarm_handler(int sig_nr)
{
  LOG("ERROR: sig_alarm_handler() called!");
  longjmp(g_progzust_timeout, 1);
}

int CModBusTCP::Read(int nAddr, short* pnValue, int nWordCount)
{
  TRACE("CModBusTCP::Read(%d, %p, %d)", nAddr, pnValue, nWordCount);

  if (signal(SIGALRM, sig_alarm_handler) == SIG_ERR)
  {
    LOG("ERROR: signal(SIGALARM, sig_alarm_handler) failed!");
    return -11;
  }
  if (setjmp(g_progzust_timeout) != 0)
  {
    LOG("ERROR: Timeout CModBusTCP::Read(%d, %p, %d)?!", nAddr, pnValue, nWordCount);
    return -12;
  }

  alarm(1);
  int nResult = m_mbusProtocol.readMultipleRegisters(1, nAddr, pnValue, nWordCount);
  alarm(0);

  if (nResult != FTALK_SUCCESS)
  {
    LOG("ERROR: %s!", getBusProtocolErrorText(nResult));

    return -1;
  }

  for (int i=0; i < nWordCount; i++)
    TRACE("[%d]: %d\n", nAddr+i, *(pnValue+i));

  return 0;
}

int CModBusTCP::Write(int nAddr, short* pnValue, int nWordCount)
{
  TRACE("CModBusTCP::Write(%d, %p, %d)", nAddr, pnValue, nWordCount);
  for (int i=0; i < nWordCount; i++)
    TRACE("[%d]: %hd\n", nAddr+i, *(pnValue+i));

  if (signal(SIGALRM, sig_alarm_handler) == SIG_ERR)
  {
    LOG("ERROR: signal(SIGALARM, sig_alarm_handler) failed!");
    return -11;
  }
  if (setjmp(g_progzust_timeout) != 0)
  {
    LOG("ERROR: Timeout CModBusTCP::Write(%d, %p, %d)?!", nAddr, pnValue, nWordCount);
    return -12;
  }

  alarm(1);
  int nResult = m_mbusProtocol.writeMultipleRegisters(1, nAddr, pnValue, nWordCount);
  alarm(0);

  if (nResult != FTALK_SUCCESS)
  {
    LOG("ERROR: %s!", getBusProtocolErrorText(nResult));
    return -1;
  }

  return 0;
}