{"id":9044,"date":"2019-08-06T14:34:42","date_gmt":"2019-08-06T19:34:42","guid":{"rendered":"https:\/\/blogs.mathworks.com\/simulink\/?p=9044"},"modified":"2019-08-06T14:34:42","modified_gmt":"2019-08-06T19:34:42","slug":"loading-signals-in-timetable-format","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/simulink\/2019\/08\/06\/loading-signals-in-timetable-format\/","title":{"rendered":"Loading Signals in Timetable Format"},"content":{"rendered":"

Today I decided to revisit a topic I covered a few years ago: loading discrete signals in a simulation.<\/a><\/p>\n

Let's see what has been added in the last few years to help with the potential problems you might run into when loading discrete signals in a simulation.<\/p>\n

The Problem<\/strong><\/p>\n

Let's start with a simple Excel sheet with two columns, the first one for time and the second for the signal values. I made the data identical to the time just to make the issue more obvious. The actual file we will use contains 10,000 rows, for a stop time of 10 seconds.<\/p>\n

\"Excel<\/p>\n

As I explained in this post<\/a>, it is possible to use the From Spreadsheet<\/a> block to load this signal.<\/p>\n

If you do so, I strongly recommend to be careful and NOT<\/strong> load the time column from Excel. Even though the time points in Excel might look equally spaced, they might not be equally spaced in the same way as Simulink time steps. If there is a discrepancy, you might end up with duplicated or missing points.<\/p>\n

For the file shown above, here is what the output looks like if you use the default settings in the From Spreadsheet block. The spikes on the bottom axis are indications that points are missed or duplicated.<\/p>\n

\"Excel<\/p>\n

See this post<\/a> for more details on how to configure the From Spreadsheet block to avoid this issue.<\/p>\n

For today's example, I am adding an additional level of complexity:<\/p>\n