Proposal for enhancement in Blocks.Tables.CombiTable1D,1Ds,2D and Blocks.Sources.CombiTimeTable

[modelica-trac-importer]

Reported by gfontanella on 19 Oct 2011 12:43 UTC
Currently the table models in Modelica.Blocks.Tables do not allow the user to set any other interpolation method than the linear and the first derivative coutinuous ones.

I think it might be useful to add a "No interpolation" option, where each sampled value is simply held until the next one occurs.

This could really come in handy whenever the original data is stored by a monitoring system which only logs a value when this is different from the previously registered one.

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Migrated-From: https://trac.modelica.org/Modelica/ticket/628

[modelica-trac-importer]

Comment by ahaumer on 19 Oct 2011 17:17 UTC
For Sources.CombiTimeTable this is rather clear, since time is continuously increasing and whenever a new time value of the table definition is reached, the ouput jumps to the new value; this makes sense to model switching behaviour stored in the table.
For Tables.CombiTable1D,1Ds,2D which interpolate with respect to an input which could also decrease this has to be considered carefully.

[modelica-trac-importer]

Comment by ahaumer on 19 Oct 2011 17:27 UTC
As a workaround, you would have to define the table in a special way - here is an example:
Instead of table=[0, 0; 2.5, 1; 3, 0] - which defines a triangle for linear interpolation - you have to define steps: table=[0, 0; 2.5, 0; 2.5, 1; 3, 1; 3, 0] - which defines a step 0->1 at time = 2.5 and a step 1->0 at time = 3.

[modelica-trac-importer]

Modified by ahaumer on 2 Mar 2012 09:08 UTC

[modelica-trac-importer]

Comment by anonymous on 10 Dec 2012 16:22 UTC
This feature request could also be part of the upcoming call for a quotation.

[modelica-trac-importer]

Comment by otter on 2 Jan 2013 20:58 UTC
This feature has been included in the call for quotations for an open source implementation of the MSL table blocks and will therefore be included in MSL 3.2.1.

[modelica-trac-importer]

Changelog removed by otter on 2 Jan 2013 20:58 UTC

[modelica-trac-importer]

Comment by otter on 20 May 2013 07:32 UTC
Fixed in 8b1c969:

The new open source implementation of block Modelica.Blocks.Sources.CombiTimeTable contains a new option Smoothness.ConstantSegments in order to not interpolate but only hold the last value.

[modelica-trac-importer]

Changelog modified by otter on 20 May 2013 07:32 UTC
New feature of CombiTimeTable block: Optionally, the table values are not interpolated but the hold during the table points