Recipe and table management

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1

Hi everyone,

I have a few questions regarding a project I’m currently working on.

I am developing a system to save XML recipes onto a USB stick connected to a PLC. Saving works fine so far, but I would like to add a feature that allows the user to assign a name to each recipe.

To do this, I created a string array where all the recipe names are stored. When loading a recipe, I retrieve the name from this array.

I have two questions:

  1. Dynamic table display:
    I am using a table widget to display the recipe names. If, for example, only the first 10 entries in the array are filled and the rest are empty, how can I make the table display only the filled entries and hide the empty rows?

  2. Deleting files from the USB stick:
    What is the recommended way to delete files directly from the USB stick connected to the PLC?

Thank you in advance for your help!

2

Hi Mohamed,

Dynamic table display:
Table widget has a property “tableConfiguration” that can be binded to a string variable with the correct JSON syntax.
Check this property in Table documentation for a description of the syntax and the possibilities

Here is a code I used in a project to generate this JSON with functions from AsBrStr :

// Generate configuration of Table widget to hide empty rows
// based on this syntax (see Table widget documentation) : {"specRows": [ {"from":0, "to":10, "visible":false} ]}

      brsmemset(ADR(TableConfig), 0, SIZEOF(TableConfig));
      brsstrcat(ADR(TableConfig), ADR('{"specRows": [{"from":'));
      tmpStr1 := UINT_TO_STRING(RecipeNum);
      brsstrcat(ADR(TableConfig), ADR(tmpStr1));
      brsstrcat(ADR(TableConfig), ADR(', "to":'));
      tmpStr1 := UINT_TO_STRING(REC_REC_NUM);
      brsstrcat(ADR(TableConfig), ADR(tmpStr1));
      brsstrcat(ADR(TableConfig), ADR(', "visible":false}]}'));

In this example, TableConfig variable is generated in a way that widget should hide rows from “RecipeNum” to “REC_REC_NUM” :

  • TableConfig is the string variable binded to the widget,
  • RecipeNum is the index of the first row to hide,
  • REC_REC_NUM the maximum index of the array

Deleting files from the USB stick:
If you already managed to detect the USB stick and save files into it, you have done the worst part of the job :slight_smile: For deleting files you can use the FB FileDelete from FileIO library.
It just needs name of the file device and name of the file.

Best regards,

3

Hi Guillaume,

Thank you for the code and the explanation — it worked perfectly for me.

I also noticed the file handling function blocks, and I was wondering if you know whether there is a function that can read all file names from a USB stick (or from a specific folder on it), so I can display them in a table.

I came across DirRead, but from the documentation, I understood that it only reads one file name at a time rather than the entire folder. I might have misunderstood it, so I’m not completely sure. Do you have any suggestions on how to handle this?

Thanks again for your help — I really appreciate it.

4

Hi Mohamed,

You’re right DirRead actually only read one file at a time, you need to call it multiple times and use the entry input to get all the files.

Check Example of DirInfo and DirRead in Structured Text :

After every success (status = 0), it increases entry counter to get info of the next file.