Utilisez la bibliothèque opcua-asyncio pour créer un service et un client OPC UA, lire et écrire des valeurs de balises

1. Vous devez d'abord installer Anaconda3
2. Utilisez pip pour installer la bibliothèque opcua-asyncio

pip install asyncua

3. server.py qui peut être exécuté directement

import logging
import asyncio
import sys
sys.path.insert(0, "..")

from asyncua import ua, Server
from asyncua.common.methods import uamethod


logging.basicConfig(level=logging.INFO)
_logger = logging.getLogger('asyncua')


@uamethod
def func(parent, value):
    return value * 2


async def main():
    # setup our server
    server = Server()
    await server.init()
    server.set_endpoint('opc.tcp://0.0.0.0:4840/freeopcua/server/')

    # setup our own namespace, not really necessary but should as spec
    uri = 'http://examples.freeopcua.github.io'
    idx = await server.register_namespace(uri)

    # populating our address space
    # server.nodes, contains links to very common nodes like objects and root
    myobj = await server.nodes.objects.add_object(idx, 'MyObject')
    myvar = await myobj.add_variable(idx, 'MyVariable', 6.7)
    # Set MyVariable to be writable by clients
    await myvar.set_writable()
    await server.nodes.objects.add_method(ua.NodeId('ServerMethod', 2), ua.QualifiedName('ServerMethod', 2), func, [ua.VariantType.Int64], [ua.VariantType.Int64])
    _logger.info('Starting server!')
    async with server:
        while True:
            await asyncio.sleep(2)
            new_val = await myvar.get_value() + 0.1
            _logger.info('Set value of %s to %.1f', myvar, new_val)
            await myvar.write_value(new_val)


if __name__ == '__main__':
    asyncio.run(main())

4. Client.py qui peut être exécuté directement

import asyncio
import sys
# sys.path.insert(0, "..")
import logging
from asyncua import Client, Node, ua

logging.basicConfig(level=logging.INFO)
_logger = logging.getLogger('asyncua')


async def main():
    url = 'opc.tcp://localhost:4840/freeopcua/server/'
    # url = 'opc.tcp://commsvr.com:51234/UA/CAS_UA_Server'
    async with Client(url=url) as client:
        # Client has a few methods to get proxy to UA nodes that should always be in address space such as Root or Objects
        # Node objects have methods to read and write node attributes as well as browse or populate address space
        mytags = await client.nodes.root.get_children()
        #获取根目录下所有node节点
        _logger.info('孩子 of root children are: %r', mytags)
        #获取根目录节点
        _logger.info('孩子 of root are: %r', client.get_root_node())
        mytag1 = await mytags[0].get_children()
        mytag2 = await mytag1[1].get_children()
        #获取指定node下所有node节点,没有返回"[]"
        _logger.info('孩子 of root are: %r',mytag2[0])
        
        uri = 'http://examples.freeopcua.github.io'
        idx = await client.get_namespace_index(uri)
        # get a specific node knowing its node id
        var2 = await client.get_node("i=84").get_children()
        #var2tmp = var2.get_children()
        #_logger.info('Children of root are: %r', var2tmp)
        # var = client.get_node("ns=3;i=2002")
        var = await client.nodes.root.get_child(["0:Objects", f"{idx}:MyObject", f"{idx}:MyVariable"])
        #读取一个node的变量值
        print("My variable", var, await mytag2[0].read_value())
        mytag3 =await mytag2[0].get_children()
        print(var2)
        #写入一个node的变量值
        await mytag2[0].write_value(3.9)
        # print(var)
        # await var.read_data_value() # get value of node as a DataValue object
        # await var.read_value() # get value of node as a python builtin
        # await var.write_value(ua.Variant([23], ua.VariantType.Int64)) #set node value using explicit data type
        # await var.write_value(3.9) # set node value using implicit data type

if __name__ == '__main__':
    asyncio.run(main())