fbs2plc.exe - Use Flatbuffers in your PLC project¶

A lot of ctrlX Data Layer nodes contain structured data stored in the Flatbuffers format.

The data structure is defined in a schema file (.fbs file). The FlatBuffers compiler flatc is able to compile such a .fbs file into code for several programming languages including IEC 61131-3 Structured Text (ST).

This guide describes how one or more fbs files can be compiled into IEC 61131-3 ST code and how this code can be imported and used in your IEC 61131-3 project to handle Flatbuffers.

The described workflow and the tools are currently running only under Windows 10.

Prerequisites¶

ctrlX WORKS¶

Install ctrlX WORKS >= 1.20 with the function 'ctrlX PLC Engineering' and 'App Build Environment'.

We recommend to use "C:\Program Files\Rexroth\ctrlX WORKS" as installation path. In this case the path to ctrlX PLC Engineering is "C:\Program Files\Rexroth\ctrlX WORKS\Studio\Common\ctrlX-PLC-Engineering.exe"

ctrlX CORE¶

Create a ctrlX CORE^virtual with Port Forwarding and start it.
Install the PLC snap.

ctrlX AUTOMATION SDK¶

On your Windows host¶

Download the ctrlX AUTOMATION SDK and extract it to c:\ctrlx-automation-sdk

Now two executables are available:

c:\ctrlx-automation-sdk\bin\oss.flatbuffers\win-msvc-x64\release\flatc.exe
c:\ctrlx-automation-sdk\bin\fbs2plc\win-x64\fbs2plc.exe

On your App Build Environment¶

From ctrlX WORKS, create and start an App Build Environment.
Login into your App Build Environment: ssh -p 10022 boschrexroth@127.0.0.1
Password is boschrexroth
Install the ctrlX AUTOMATION SDK

$ ~/scripts/install-sdk.sh
Build a required snap (here amd64) and install it on the ctrlX CORE^virtual

$ cd ~/ctrlx-automation-sdk/samples-cpp/datalayer.provider.all-data $ ../../scripts/build-upload-log-snap.sh -PF
Open a web browser, login into your ctrlX CORE^virtual. A Data Layer node sdk-cpp-alldata/dynamic/fbs should exist.

This node later can be read, changed and written by our IEC 61131-3 PLC code.

Reading and writing a flatbuffers ctrlX Data Layer node in your PLC project¶

The basic steps are:

Create a PLC library which contains the IEC61131 ST code to handle a Flatbuffers variable
Create a new PLC project
Import the created PLC library and provided sample code into your project
Compile the project and log into your ctrl CORE^virtual

Create a PLC library¶

Start cmd.exe and enter these commands:

c:
cd \ctrlx-automation-sdk\samples-fbs2plc\sampleSchema
start.bat

Result: * The file c:\ctrlx-automation-sdk\samples-cpp\datalayer.provider.all-data\sampleSchema.fbs was compiled into IEC61131 code. * A new PLC library fbs-sampleSchema was created, using c:\ctrlx-automation-sdk\plc\CXA_fbs_Template.library as template. * All required standard libraries were imported. * ctrlX PLC Engineering now has the new library opened.

Store the new library so that you can use it in your PLC project:

Select File - Save project and install into library repository
Close the libray
Keep ctrlX PLC Engineering running

Create a PLC project¶

In ctrlX PLC Engineering create a new PLC project use 'ctrlX CORE x64 Project' as template.
Select the node Application and delete it.
Select the node PLC Logic
Select menu item Project - PLCopenXML import..., select c:\ctrlx-automation-sdk\samples-fbs2plc\sampleSchema\fbs-read-write.xml
Double click the node library manager
Add the library CXA_DATALAYER to your project.
Connect the device of ypur PLC project with the ctrlX CORE^virtual
Login into your ctrlX CORE^virtual

Check the Flatbuffer Access¶

From a web browser login into your ctrlX CORE^virtual Web UI
Select Settings - Data Layer
Expand the Data Layer tree: sdk-cpp-alldata/dynamic/fbs

The values of the x, y, z variables should be changed by our PLC program.