send wrong!

[crestxa]

  myData[0]:=$01;
  myData[1]:=$1F;
  myData[2]:=$01;
  myData[3]:=$00;
  myData[4]:=$04;
  myData[5]:=$00;
  myData[6]:=$97;
  myData[7]:=$34;
if   nrComm1.SendData(@myData[0], 8);  it send wrong data,
but if
  nrComm1.SendData(@myData[0], 4);
  nrComm1.SendData(@myData[4], 4);

it's ok!
why?