resample
Resample OPC HDA data object to have defined time stamps
Syntax
NewObj = resample(DObj,NewTS)
NewObj = resample(DObj,NewTS,'linear')
NewObj = resample(DObj,NewTS,'hold')
NewObj = resample(DObj,NewTS,'nearest')
NewObj = resample(DObj,NewTS,'spline')
NewObj = resample(DObj,NewTS,'pchip')
Description
NewObj = resample(DObj,NewTS)
resamples data in OPC HDA data
object DObj
so that all elements of the object have the time
stamps given by NewTS
. NewTS
must be a vector
of MATLAB® date numbers.
If DObj
contains elements with the same item ID, those elements
are combined into one element. So the size of NewObj
might be
smaller than the size of DObj
.
Values are linearly interpolated or extrapolated to the new time stamps.
Quality for the resampled data is set as follows:
All original values retain their quality.
All interpolated values get a quality of
Interpolated: Good
.All extrapolated values get a quality of
Interpolated: Sub-Normal
.
NewObj = resample(DObj,NewTS,'linear')
uses linear
interpolation.
NewObj = resample(DObj,NewTS,'hold')
uses a zero-order hold
interpolation where the previous known value is used for all new time stamps. Any
time stamp prior to the first known value is set to NaN
(or
0
if the value is a fixed-point data type).
NewObj = resample(DObj,NewTS,'nearest')
uses nearest-neighbor
interpolation as defined by interp1
.
NewObj = resample(DObj,NewTS,'spline')
uses spline
interpolation as defined by interp1
.
NewObj = resample(DObj,NewTS,'pchip')
uses shape-preserving,
piece-wise, cubic interpolation as defined by interp1
.
Examples
Load the OPC HDA example data file and resample the first element of
hdaDataSmall
.
load opcSampleHdaData;
newTS = datenum(2010,6,1,9,30,0:10:60);
newObj = resample(hdaDataSmall(1),newTS);
Display the values and qualities of the new object.
newObj.showValues