private static void checkRetCode(ERRCODES retCode, string msg)
 {
     if (retCode != ERRCODES.DRV_SUCCESS && retCode != ERRCODES.DRV_ACQUIRING)
     {
         throw new CamApiException(msg, retCode);
     }
 }
 public CamApiException(string message, ERRCODES errCode) : base(message)
 {
     ErrCode = errCode;
 }