JSON Application Example

Description

This application example demonstrates the usage of the JSON Library

This application example consists of two parts.

1. Showing the usage of the library in a PLC Program, which can be downloaded to a 1500 PLC or PLCSIM Advanced
2. Many examples as UnitTest in the test folder

Execute the Application Example (AX Code local)

1. Open a command line interface (CLI) and switch to the target folder. Example, if the traget folder is D:\temp

   D:
   cd \temp

2. Install the application example on your local PC

   Run the following commands in a CLI

   apax create @simatic-ax/ae-json-library --registry https://npm.pkg.github.com ae-json-library

   Switch to the project directory

   cd ae-json-library 

   install the dependencies with:

   apax install

   and open AxCode

   axcode . 

Description of the PLC program

The PLC program executes different steps:

1. CreateDocument1 Add an JSON element of type Integer with value 1234 in a empty JSON document doc

2. SerializeDocument1

   doc.Serialize(doc.buffer) serializes the JSON document doc into the array of char (doc.buffer).

   Expected result in the array of char: {"myInt": 1234}

   In this step, the time for serializing will be measured and stored in the variable TimeCreationDocument1. The result od serializing will be stored in the string variable SerializedDocument1

3. ParseDocument1

   Parse the JSON document doc for the key = myInt and get the value 1234

4. ResetJSonDocument1

   Delete all JSON elements in the JSON document doc. So it's possible to create a new JSON document with other JSON elements.

5. CreateDocument2

   Create a JSON document with nested JSON elements. Structure of nested JSON document:

   doc 
    |
    +- myBoolean(value = true)
    |
    +- myObject -+- myInt(value = 1234)
                 | 
                 +- myDint(value = 12345678)
   

6. SerializeDocument2

   doc.Serialize(doc.buffer) serializes the JSON document doc into the array of char (doc.buffer).

   Expected result in the array of char: {"myBoolean": true, "myObject": {"myInt": 1234, "myDint": 12345678}}

   In this step, the time for serializing will be measured and stored in the variable TimeCreationDocument2. The result od serializing will be stored in the string variable SerializedDocument2

7. ParseDocument2

   Parse the JSON document doc for the key = myDint and get the value 12345678

8. ResetJSonDocument2

   Delete all JSON elements in the JSON document doc. So it's possible to create a new JSON document with other JSON elements.

Start the application example

1. Start a PLCSIM Advanced Instance or using a 1500 PLC. Download a TIA Portal created HWCN with a 1500 standard PLC (Default IP Address 192.168.0.1).

   The default ip address can be changed in the apax.yml and in the .vscode/launch.json

   IP_ADDRESS: "192.168.0.1"

   {
      "version": "0.2.0",
      "configurations": [
         {
               "name": "Debug live on PLC",
               "type": "plc-debug",
               "request": "launch",
               "program": "${workspaceFolder}",
               "ip": "192.168.0.1"
         }
      ]
   }

2. If not open, open a terminal in AX Code (CTRL+SHIFT+ö)

3. Start the application example

   apax dlplc
   

   1500 is required, if you use a real 1500 PLC instead of PLCSIM Advanced.

4. Monitor variables with mon-File:

   

   1. Open the file default.mon
   2. Enable monitoring
   3. Observe the values

Contribution

Thanks for your interest in contributing. Anybody is free to report bugs, unclear documentation, and other problems regarding this repository in the Issues section or, even better, is free to propose any changes to this repository using pull requests.

Markdownlint-cli

This workspace will be checked by the markdownlint-cli (there is also documented ho to install the tool) tool in the CI workflow automatically.
To avoid, that the CI workflow fails because of the markdown linter, you can check all markdown files locally by running the markdownlint with:

markdownlint **/*.md --fix

License and Legal information

Please read the Legal information