Scheduling and long task-execution

2020-02-27T20:50:13.712000Z

Originally created by: Nicolai_Hanssing

spfeif hat geschrieben:
Interesting that the task takes so long. Typically you have a watchdog timer that wouldn't let something run for more that ~100msec.
How are the recipes given to you and how many and often are they received? Maybe you can do the following:

They are not recieved, but made online while the application is running (2 axis Scara-robot and several more servos and IO). When the operator wants to store the current active recipe, I insert it into the array, sort it, and I store the whole array on disk. Array is fixed size of 300, and is allways loaded into memory during bootup.

If the array is allready sorted it does not take long, about 7-30ms.

However if its is not, which was my testcase, and have long string as names like '0000001' '0000002' etc, then it took quite a while. The string compare function takes longer due to the names, and the sorting was worst-case for a bubble-sort.

Seeing its not an issue during production, as the array is allways sorted except for the new insert, I'll just leave it be.

Actually the write-access onto a flash-card afterwards takes longer, it takes 500ms or more.

Nicolai

Scheduling and long task-execution

2020-02-27T20:50:09.814000Z

Interesting that the task takes so long. Typically you have a watchdog timer that wouldn't let something run for more that ~100msec.

How are the recipes given to you and how many and often are they received? Maybe you can do the following:

Create a multi-dimensional array.

Sorted[1..26,1..100] of MyRecipe;

When received look at the first character of the name and add it to the array like. A = 1 B= 2, C=3, Z=26. Instead of sorting all the time you can break the sort into smaller chunks. So if you get a new recipe "Cookies" you can add it to the Sorted[char(C) - 64,uLastIndex] then sort only Sorted[3,100] instead of all recipes. Because it sounds more like you are inserting instead of resorting?

Or if you have control of it add an id to the recipe and let the software outside of the PLC sort them?

Scheduling and long task-execution

2020-02-27T20:50:08.382000Z

Originally created by: Nicolai_Hanssing

Hi One clear question for you:

System:

CoDEsys 2.3.7.5

Running in a multi-task enviroment, I have a low-priority task that does a sorting on a large array, wich sometime takes a long while to finish (several seconds).

Will the scheduler restart the process on top of itself, as it is scheduled to run with a fixed cycle of 100ms?

I've been unable to find a clear description of this, I assume not.

NExt question:

ANyone have a good way of sorting an array of structs, by a string inside the struct.

Right now i've made a String-compare-function using OSCAT, that is called and returns that Str1>Str2, Str1<Str2 or Str1=Str2, .....

and then do a cocktail-sort (bubble-variant)

Issue is sorting an array of recipies by their recipe-name.

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