Configuration of the PLCnext Runtime Services 

 

Default PLCnext Runtime Services of the app types

 

 

Some app types such as a solution require certain PLCnext System Services such as PROFINET® by default for execution. So that the app developer does not have to know these necessary PLCnext System Services in advance and enter them in the app description, they are included in the system by default.

The following applies:

• Default system services that are explicitly configured in the app description are overwritten with the corresponding actions/values of the app description.
• Default configurations of the apps are checked for inconsistency when several app types are used in one app container.

 

First, the following default PLCnext System Services with the corresponding actions (see “Configuration of the PLCnext Runtime Services”) are defined or considered in the system:

 

"EngineerApp":

• "IEC": "EXCLUSIVE_ACCESS"
• "PROFINET": "EXCLUSIVE_ACCESS"
• "EHMI": "EXCLUSIVE_ACCESS"
• "OPCUA": "MUST_HAVE"

The following system services must not be configured or switched off via PLCnext Apps:

• AppManager
• PLCnext Store
• Proficloud

 

When configuring PLCnext Services in an app, the default settings of an app type are overwritten if they match. The following must be observed:

• The "plcnextservices" entry is not present in the app description: If a service ID occurs several times with inconsistent actions in the default configurations, an inconsistency error is reported (see following section) and the app installation is prevented.
• The "plcnextservices" entry is present in the app description: If a service ID occurs several times in the default configurations, these are removed and replaced with the "one" service setting from the app description.

Consistency check of the PLCnext Runtime Services

The actions (MUST_HAVE, MUST_NOT_HAVE and EXCLUSIVE_ACCESS) of the individual PLCnext features are evaluated. An inconsistency of the configurations for a PLCnext System Service occurs in at least one of the following cases:

• A PLCnext System Service has at least two different actions at several points simultaneously. E.g. in one app MUST_HAVE and in another MUST_NOT_HAVE
• A PLCnext System Service has at least two simultaneous actions of type EXCLUSIVE_ACCESS in at least two places.

For aPLCnext System Service, the following combinations of actions are permissible at the same time:

• Several entries only with the action MUST_HAVE or several entries only with the action MUST_NOT_HAVE.
• Or only one EXCLUSIV_ACCESS entry.

 

Consistency check is done on:

• App start: An app with inconsistent service configurations may not start.
• System start: Any already started app with inconsistent service configurations will be stopped. 

Specifications and restrictions

• The affected services are to be switched off at system start of the runtime. I.e. a restart of the firmware is necessary after  app start.
• It is not possible to switch off/on PLCnext Services at runtime.
• PLCnext Runtime Services configuration is activated/deactivated when you start/stop the app.
• The original PLCnext System state can be restored after stopping of the app.
• The activation/deactivation of PLCnext Runtime Services requires a restart of the firmware.

Demo app to configure PLCnext Runtime Services

In the demo app for configuring PLCnext System Services, the Wbm-Plcnext component is switched off. For this the action "MUST_NOT_HAVE" is configured for the PLCnext Service with the ID "WBM", therefore the name "SC_WBM-MNH" is selected for the app.

 

The app description for the WBM Deactivator app is as follows:

{
   "plcnextapp":
      {
         "name": "WBM Deactivator",
         "identifier": "10000010000003",
         "version": "22.10.1 alpha",
         "target": "AXC F 2152",
         "minfirmware_version": "19.0.0",
         "manufacturer": "PhoenixContact",
         "licensetype": "Free"
      },
   "plcnextservices" :
      [
         {
            "service" : "WBM",
            "action" : "MUST_NOT_HAVE"
         }
      ]
   }

In the following sources for the demo PLCnext Services Config App are available on GitHub HERE:

• App container folder:
  • app description file app_info.json
• Demo app container file: WbmDeactivator.app