Subscribing to events
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A controller can subscribe to all OIDs it is interested in receiving notifications from by using the Subscription message.
Example message for subscribing to multiple OIDs.
{
"messageType": 3,
"subscriptions": [
1,
100,
111,
98119
]
}
Example SubscriptionResponse message received
{
"messageType": 4,
"subscriptions": [
1,
100,
98119
]
}
Note in this example, 111 was removed from the response subscriptions array because it was not a valid OID for subscribing.
Example notification for the PropertyChanged event (1e1) when the userLabel property (1p6) changes on object with OID 98119
{
"messageType": 2,
"notifications": [
{
"oid": 98119,
"eventId": {
"level": 1,
"index": 1
},
"eventData": {
"propertyId": {
"level": 1,
"index": 6
},
"changeType": 0,
"value": "Input 1",
"sequenceItemIndex": null
}
}
]
}
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