Difference between revisions of "Open Control Architecture"
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<pre> | <pre> | ||
global.get(" | var localNetworkId = global.get("localNetworkId"); | ||
var node = global.get("node"); | |||
var reading = global.get(localNetworkId + "." + node + ".dat.outputTemperature"); | |||
var output = "The value of " + reading.title + " is " + reading.value + reading.units; | |||
// "The value of Output Temperature is 35°C | |||
</pre> | </pre> |
Revision as of 16:22, 29 May 2022
The Open Controls described on this site works as follows:
- Communications between systems is performed using MQTT using a standardised 5 level topic structure. network / node / device / group / key.
- A device managing communications is called a node.
- Data from within a node or from connected devices is assigned a local network identifier of "local" so that the node can separate internal traffic and readings from general traffic. This is stored under global.localNetworkId
- The external network identifier is stored under global.networkId
- The node identifier is stored under global.node
- Attributes for data may be loaded from a central index (GitHub hosted), providing additional information such as units and descriptions. This is to avoid the need to locally describe data, and to assist in compatibility.
- Controls software is written in Node-RED.
- Within Node-RED, data and attributes are stored within the global.readings object.
- Data within the readings object is nested according to the topic (excluding the node as more than one node may publish data on a device).
e.g. a message with a topic myNetwork/node123/myDevice/dat/outputTemperature would be stored in (global).readings.myNetwork.myDevice.dat.outputTemperature.value
The following code could be used to read data and its attributes for output.
var localNetworkId = global.get("localNetworkId"); var node = global.get("node"); var reading = global.get(localNetworkId + "." + node + ".dat.outputTemperature"); var output = "The value of " + reading.title + " is " + reading.value + reading.units; // "The value of Output Temperature is 35°C