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-iec61131\fbs2plc
start.bat

Result: * The file ctrlx-automation-sdk\samples-cpp\datalayer.provider.alldata\sampleSchema.fbs was compiled into IEC61131 code. * A new PLC library fbs-sampleSchema was created, using 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.

Note Paths are examples and must be adapted locally.

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 ctrlx-automation-sdk\samples-iec61131\fbs2plc\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.