The most convenient deployment of the jsonToolkit in cloud connectivity is to connect directly from the controller schema
to the remote transport. However, if a controller does not have remote connectivity, a
Supervisor is required. There are a few options to consider.
NiagaraNetwork point export
You import points from subordinate controllers into a
Supervisor under the NiagaraNetwork and create
Supervisor schemata.
- Schema queries and bindings may target points under the NiagaraNetwork and subscription (change of value) will work ok.
- Some information, such as the parent name and original slot path of the points, may not be available in the schemata.
- Tag data and permissions may need to be redefined at the
Supervisor level.
- Alarms and histories need to be imported to the
Supervisor if you require these data for your schema.
- This approach requires the most configuration overhead and may not be desirable to import all the points to the
Supervisor.
System database
Use the system database to index subordinate controllers and sys: ords for queries within a
Supervisor schema.
- Example schema query:
station:|sys:|neql:n:point|bql:select name, out.value, out.status
- Example schema base query:
station:|sys:|neql:n:point|bql:select *
- Subscription to the remote points works so that change of value is available, as is the parent name and original slot path
of the points.
- You cannot use a system database ord for a specific point binding.
- This option is not suitable for export of alarms and histories.
NiagaraNetwork schema export
The schema runs locally on each controller and is linked to a StringWritable. This writable point is then imported into the
Supervisor and linked to remote transport.
- It makes sense to do the processing at the data source where full point fidelity is available.
- The framework deals with permissions locally at each station.
- You have full alarm and history support.
- Linking the imported StringWritable to a transport, such as MQTT, keeps the point subscribed.
Proxy
If you are using MQTT as your transport, you may set up an intermediary broker to proxy messages to the remote broker. This
solution requires extra IT overhead and support.