.. highlightlang:: us

.. index:: NC_SynchronizeTime

.. _nc_synchronizetime:

NC_SynchronizeTime
==================

.. us.tag  NC_SynchronizeTime ENGLISH nc.misc New5148 Changed5603

This function can be used to calculate the time offset (delay) between two data 
files. Example: Data files from two different data loggers that have been 
triggered manually.

Both data files must have a time signal and a sync channel. For example:
engine or vehicle speed.

The time data must be measured in the same unit, i.e. seconds. The
resolution in both files can be different.

The time offset is calculated by a cross correlation, therefore, the sync signal
should not be constant. If the calculation of the offset fails the offset
can be set manually. 

Only the first 250000 data points are used to calculate the offset.

.. function::  ssNCNewFile = NC_SynchronizeTime(ssNCFile1, ssTime1, ssSyncChannel1, ssNCFile2, ssTime2, ssSyncChannel2)
    ssNCNewFile = NC_SynchronizeTime(ssNCFile1, ssTime1, ssSyncChannel1, ssNCFile2, ssTime2, ssSyncChannel2, bMerge)
    ssNCNewFile = NC_SynchronizeTime(ssNCFile1, ssTime1, ssSyncChannel1, ssNCFile2, ssTime2, ssSyncChannel2, bMerge, bInterpolate)
    ssNCNewFile = NC_SynchronizeTime(ssNCFile1, ssTime1, ssSyncChannel1, ssNCFile2, ssTime2, ssSyncChannel2, bMerge, bInterpolate, bUseOffset)
    ssNCNewFile = NC_SynchronizeTime(ssNCFile1, ssTime1, ssSyncChannel1, ssNCFile2, ssTime2, ssSyncChannel2, bMerge, bInterpolate, bUseOffset, rsOffset)
    ssNCNewFile = NC_SynchronizeTime(ssNCFile1, ssTime1, ssSyncChannel1, ssNCFile2, ssTime2, ssSyncChannel2, bMerge, bInterpolate, bUseOffset, rsOffset, nUseTimeChannel)
    ssNCNewFile = NC_SynchronizeTime(ssNCFile1, ssTime1, ssSyncChannel1, ssNCFile2, ssTime2, ssSyncChannel2, oParameter)

.. us.return

**Return Value**

Name of the NC file or an empty string, if an error occurs. 

.. us.params

**Parameters**

.. uparam:: ssNCFile1

   *ssNCFile1* is the name of a NC file.

.. uparam:: ssTime1

   *ssTime1* is the time channel name of file 1.

.. uparam:: ssSyncChannel1

   *ssSyncChannel1* is the signal name of file 1.

.. uparam:: ssNCFile2

   *ssNCFile1* is the name of a NC file.

.. uparam:: ssTime2

   *ssTime1* is the time channel name of file 2.

.. uparam:: ssSyncChannel2

   *ssSyncChannel1* is the signal name of file 2.

.. uparam:: oParameter

   Is an oject with the following elements:

   .. list-table::
      :header-rows: 1

      * - Element
        - Default Value
        - Description
      * - bMerge
        - TRUE (1)
        - If *bMerge* is TRUE (1), the channels of both files will be merge into
          one file.
      * - bInterpolate
        - TRUE (1)
        - If  *bInterpolate* is TRUE (1), the channels will be interpolated onto
          one time base.
      * - bUseOffset
        - FALSE (0)
        - If *bUseOffset* is FALSE (0), the delay will be calculated. If TRUE (1)
          the offset can be set in the parameter *rsOffset*.
      * - rsOffset
        - No default value
        - Is the time offset. Is used if *bUseOffset* is TRUE (1).
      * - nUseTimeChannel
        - 0
        - If *nUseTimeChannel* is set to 0 a dialog box will be displayed to
          select the time channel for the interpolation. If set to 1 the time
          channel of the first data file is used for the interpolation. If set to
          2 the time channel of the second data file is used for the
          interpolation.
      * - rsXStartSync
        - not defined
        - This parameter should only be added to the object if only a section
          of the data should be used for the offset calculation. X-Koordinates
          are set so that they start with 0.
      * - rsXEndSync
        - not defined
        - This parameter should only be added to the object if only a section
          of the data should be used for the offset calculation. 

.. uparam:: bMerge

   If *bMerge* is TRUE (1), the channels of both files will be merge into one
   file. Default value is TRUE.

.. uparam:: bInterpolate

   If  *bInterpolate* is TRUE (1), the channels will be interpolated onto one
   time base. Default value is TRUE.

.. uparam:: bUseOffset

   If *bUseOffset* is FALSE (0), the delay will be calculated. If TRUE (1) the
   offset can be set in the parameter *rsOffset*. Default value is 0. 

.. uparam:: rsOffset

   Is the time offset. Is used if *bUseOffset* is TRUE (1). Default value is 0.

.. uparam:: nUseTimeChannel

   If *nUseTimeChannel* is set to 0 a dialog box will be displayed to select the
   time channel for the interpolation. If set to 1 the time channel of the first
   data file is used for the interpolation. If set to 2 the time channel of the
   second data file is used for the interpolation. Default value is 0.

.. us.example

**Example**

::

   bMerge = TRUE
   bInterpolate = TRUE
   bUseOffset = FALSE
   rsOffset = 0
   nUseTimeChannel = 1;

   ssNC1 = auto_ImportData("c:/a.xls")
   ssNC2 = auto_ImportData("c:/b.xls")
   ssNCNew = NC_SynchronizeTime(ssNC1, "time", "speed", ...
                                ssNC2, "time_stemp", "rpm", ...
                                bMerge, bInterpolate, bUseOffset, rsOffset, nUseTimeChannel);

   if (ssNCNew == "") {
       // Fehler
   }

**Example2**

::

   oParameter = [.];
   oParameter.bMerge = TRUE;
   oParameter.bInterpolate = FALSE;
   oParameter.bUseOffset = FALSE;
   oParameter.rsOffset = 0;
   oParameter.nUseTimeChannel = 1;
   oParameter.rsXStartSync = 0.0;
   oParameter.rsXEndSync = 100.0;

   ssNC1 = auto_ImportData("c:/a.xls")
   ssNC2 = auto_ImportData("c:/b.xls")
   ssNCNew = NC_SynchronizeTime(ssNC1, "time", "speed", ...
                                ssNC2, "time_stemp", "rpm", ...
                                oParameter);

   if (ssNCNew == "") {
       // Fehler
   }

.. us.history

**History**

.. list-table::
   :header-rows: 1

   * - Version
     - Description
   * - R2014.3
     - New parameter *oParameter*.
   * - 5.14.8
     - New.

.. seealso::
   :ref:`overview-netcdf-files`,
   :ref:`filemore-file-functionssynchronize-data-files`,
   :ref:`file-export-data`,
   :ref:`nc_create`

:sub:`id-653736`