sub LogData
{
    $SessNum =0;
    $BuffLen = 1024;
    $TempFileName = ".temp.log";

    $SiteName     = ReadVar($ConfigFile,"SiteName","____"); 

    $SessDuration = ReadVar($ConfigFile,"SessDuration",60); # Minutes
    $SessDuration *= 60*1000;  # ms

    print STDERR "Open log file $TempFileName\n";
    open(LOGFILE,">$TempFileName") or die "Can not open log file $TempFileName";

    $SIG{INT} = \&catch_zap;  # Install signall handler

    
    print "\$PASHQ,SNV\n\r";  # Query ephemeris

    undef $EndTime;

  LoggingData: while (not $Killed) 
  {
      $ReadLen = 0;
      $timeout = 60;
      eval {
       local $SIG{ALRM} = sub { die "alarm\n" };       # NB \n required
       alarm $timeout;
       $ReadLen = read(STDIN,$Buff,$BuffLen);
       alarm 0;
      };

      if ( $ReadLen > 0 )
      {
       ($Time,$LastPbnPos) = CheckTime($Buff,$EndTime);
       $SetEndTime = 0;
       $SetEndTime = 1  if ( not defined($EndTime) and defined($Time) );
       $SetEndTime = 2  if ( defined $LastPbnPos) ;
       $EndTime = $Time + ($SessDuration -  $Time % $SessDuration ) if ( $SetEndTime );

       if ( $SetEndTime == 2 )
       {
           # Write part of the buffer containing the PBN 
           # with the given yime tag to the file and then close it
           $SplitPoint = $LastPbnPos + 58;
           $SplitPoint = $ReadLen if $SplitPoint > $ReadLen;
           $Head = substr($Buff,0,$SplitPoint);
           $Tail = substr($Buff,$SplitPoint);
           syswrite(LOGFILE,$Head,$SplitPoint);
           
           print STDERR "Close log file $TempFileName\n";
           close(LOGFILE) or die "Can not close log file $FileName";

           # Give the valid name to the  temporary file
           $FileName = ComposeLogFileName($SiteName,$SessNum);
           print STDERR "Rename $TempFileName to $FileName\n";
           rename ($TempFileName,$FileName) or die "Can not rename files\n";
           
           # Open the new file, write remainder of the buffer to it
           print STDERR "Open  log file $TempFileName\n";
           open(LOGFILE,">$TempFileName") or die "Can not open file $TempFileName";
           syswrite(LOGFILE,$Tail,$ReadLen - $SplitPoint);
           
           # Make sure we have  ephemeris in the new file
           print "\$PASHQ,SNV\n\r";  
           ++$SessNum;
       }
       else
       {
           syswrite(LOGFILE,$Buff,$ReadLen);
       }
      }
  }

    if ( $Killed ) 
    {
     print STDERR "Log processed killed, clean up...\n";
     print STDERR "Close log file $TempFileName\n";
     close(LOGFILE) or die "Can not close log file $FileName";

     # Give the valid name to the  temporary file
     $FileName = ComposeLogFileName("____",$SessNum);
     print STDERR "Rename $TempFileName to $FileName\n";
     rename ($TempFileName,$FileName) or die "Can not rename files\n";

     print STDERR "Delete ID file [$LogIdFile]\n";
     unlink $LogIdFile;
    }
}

sub catch_zap {
    $Killed = 1;
}