App container A PLCnext App is stored in a SquashFS container (see Squash FS on Wikipedia). A SquashFS container stores a folder and file structure in a single compressed file. The SquashFS containers of all installed and started apps are mounted by the AppManager in the Linux file system at… Read More
Command Line Tools A Command Line Tools app part makes it possible to integrate functionalities (cmd tools) into a system that are usable via the command line and that can be started from a shell without specifying the full path to the tool executable binary. Necessary additions… Read More
License check In case of a chargeable app a license check should be integrated into the app. For this purpose the RSC service Arp::System::Lm::Services::ILicenseStatusService::GetLicenseStatus(uint32 firmCode, uint32 productCode, uint32 featureCode=0) is available. See the RSC documentation reference in the main PLCnext Info Center. This function is integrated… Read More
Configuration of the PLCnext Runtime Services If you need access or sometimes exclusive access to PLCnext System Services in your app or a PLCnext System Service is not allowed to be running when your app run, you can state this in the “plcnextservices” field of the app_info.json. This… Read More
Building a PLCnext App Independent of the amount and types of your app parts the general way to build the app is always identical. The necessary changes you need to include for every app part will be detailed below the general build process. The description of each app part… Read More
Linux Daemons A (Linux) Daemon can be integrated into a system in the form of an app. After its activation, it is entered into the Linux system start and started independently of the runtime. A daemon that is independent of the runtime is called a “Linux Daemon”. Read More
Alternative creation of an app container on a Linux desktop PC In some cases the command plcnextapp cannot be used for generating the app container, e.g. because this creation step should be integrated into a build process which cannot access a PLCnext Control. In this case the SquashFS of the app… Read More
PLCnext Engineer Solution A PLCnext Engineer Solution contains a complete PLCnext Engineer project configuration as an app part. PLCnext Engineer Solution is called in the following solution. The user of a solution does not need any programming knowledge to use the app. A solution is transferred directly from the PLCnext Store… Read More
Diagnostic log files All status and error information related to app management are saved in the following two log files: /opt/plcnext/logs/Output.log: All status and error messages of the PLCnext firmware, including those of the app management components /opt/plcnext/logs/plcnextapps.log: status and error messages of the plcnextapp command line… Read More
Shared Libraries It can happen that an exe file integrated in the app container, such as a Command Line Tool, brings its own Shared Libraries with it and needs them for its execution. Such Shared Libraries can be integrated into the app container and made known to the… Read More
