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Sorting data by ascending at sampled points, and using 1-D Lookup table to select highest OR lowest value.

Asked by Simon Fletcher on 19 Jul 2013

In my Simulink model; at every point of triggered sampling, I have 4 voltages which are measured at the same time and must be sorted into ascending order (lowest measured voltage value up to highest measured voltage value). Afterwards I want to select the highest measured value out of the 4, or the lowest measured value out of the 4.

I'm certain it is the 1-D lookup table and sort blocks which are required to be used, but there must be others as well, but I am not sure which ones? What command(s) is required to select the highest or lowest values?

EG:

Measured Values: [ 2 4 3 1]

Then to place into ascending order:

[ 1 2 3 4]

Then a command to select highest or lowest:

highest = 4

lowest = 1

I hope it is clear, it's quite straight forward I presume and I hope, I just haven't got the experience using Simulink, and the documentation doesn't really help.

Many thanks!

2 Comments

dpb on 20 Jul 2013

Do you really have to have them sorted or simply select the min/max?

Simon Fletcher on 22 Jul 2013

Yes they need to be sorted, this is because this data is to be used in another if statement; which determines if it is possible to use the lowest/highest data, if not then the 2nd highest/lowest data is to be used, then if not the 2nd, the 3rd is used and so on. Thanks for the reply.

Simon Fletcher

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1 Answer

Answer by dpb on 22 Jul 2013

OK, I "know nuthink" as per Sgt Schultz specific on Simulink but afaik you can use Matlab functions as blocks. To my surprise I didn't find a SORT block in the online doc's so you could use the Matlab sort() function. It returns the input vector sorted so the given outputs will be in a specific location. If you need the original position(s), it also has a second optional output that is the index vector of locations in the original.

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dpb

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