https://github.com/iwstkhr/opcua-subscription-sample
Python sample of subscribing data change using asyncua
https://github.com/iwstkhr/opcua-subscription-sample
opc-ua python
Last synced: 8 months ago
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Python sample of subscribing data change using asyncua
- Host: GitHub
- URL: https://github.com/iwstkhr/opcua-subscription-sample
- Owner: iwstkhr
- Created: 2022-12-04T15:52:45.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2024-08-31T15:26:04.000Z (about 1 year ago)
- Last Synced: 2025-01-05T14:21:13.344Z (9 months ago)
- Topics: opc-ua, python
- Language: Python
- Homepage:
- Size: 1000 Bytes
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# OPC UA Subscription Sample
Python sample of subscribing data change using asyncua
## Requirements
Only [asyncua library](https://github.com/FreeOpcUa/opcua-asyncio) is needed. Install it by the following command.
```sh
$ pip install asyncua
```
## Usage
First, start an OPC UA testing server which writes a random int value to a variable node every second.
The following sample Python script starts the testing server with `opc.tcp://localhost:4840`, having a variable node `MyObject/MyVariable`.
```sh
$ python server.py
Server started: OPC UA Server(opc.tcp://localhost:4840)
```
Then, run an OPC UA client script which reacts to data change notifications from the above OPC UA server.
You can define an event handler `datachange_notification` in a class and pass it to `create_subscription` function.
```sh
$ python client.py
Data change notification was received and queued.
New value 4 of "['0:Root', '0:Objects', '2:MyObject', '2:MyVariable']" was processed.
Data change notification was received and queued.
New value 79 of "['0:Root', '0:Objects', '2:MyObject', '2:MyVariable']" was processed.
Data change notification was received and queued.
New value 75 of "['0:Root', '0:Objects', '2:MyObject', '2:MyVariable']" was processed.
...
```