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 in the application via the static library "lib.Arp.System.Lm.Services.a" which is included in the PLCnext Software Development Kit.

For IEC 61131 applications, the function block LICENSE_STATUS is available in the software PLCnext Engineer in the "PLCnext Control" library. This function block represents the same function.  

When starting the app, the license status should be checked once. Further checks at runtime can also be carried out, but the status should not be polled at short intervals to avoid unnecessary system load. The app must not crash, even if no valid license is (yet) installed on the device. This is a normal state. In this case, we recommend that the app runs in a trial mode, which allows a limited user trial.