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79 lines
2.5 KiB
Markdown
79 lines
2.5 KiB
Markdown
1 year ago
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---
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icon: edit
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date: 2022-12-26
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category:
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- python
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tag:
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- opcua
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headerDepth: 5
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---
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# python 运行 opcua
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pip 安装 opcua
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``` shell
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pip install opcua
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```
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opcua 客户端
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```python
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from opcua import Client
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if __name__ == "__main__":
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client = Client("opc.tcp://localhost:4840/freeopcua/server/")
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# client = Client("opc.tcp://admin@localhost:4840/freeopcua/server/") #connect using a user
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try:
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client.connect()
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# Client has a few methods to get proxy to UA nodes that should always be in address space such as Root or Objects
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root = client.get_root_node()
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print("Objects node is: ", root)
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# Node objects have methods to read and write node attributes as well as browse or populate address space
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print("Children of root are: ", root.get_children())
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# get a specific node knowing its node id
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#var = client.get_node(ua.NodeId(1002, 2))
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#var = client.get_node("ns=3;i=2002")
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#print(var)
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#var.get_data_value() # get value of node as a DataValue object
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#var.get_value() # get value of node as a python builtin
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#var.set_value(ua.Variant([23], ua.VariantType.Int64)) #set node value using explicit data type
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#var.set_value(3.9) # set node value using implicit data type
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# Now getting a variable node using its browse path
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myvar = root.get_child(["0:Objects", "2:MyObject", "2:MyVariable"])
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obj = root.get_child(["0:Objects", "2:MyObject"])
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print("myvar is: ", myvar)
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print("myobj is: ", obj)
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# Stacked myvar access
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# print("myvar is: ", root.get_children()[0].get_children()[1].get_variables()[0].get_value())
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finally:
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client.disconnect()
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```
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opcua 服务端
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```python
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import sys
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sys.path.insert(0, "..")
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import time
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from opcua import ua, Server
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if __name__ == "__main__":
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# setup our server
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server = Server()
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server.set_endpoint("opc.tcp://0.0.0.0:4840/freeopcua/server/")
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# setup our own namespace, not really necessary but should as spec
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uri = "http://examples.freeopcua.github.io"
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idx = server.register_namespace(uri)
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# get Objects node, this is where we should put our nodes
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objects = server.get_objects_node()
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print(objects)
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# populating our address space
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myobj = objects.add_object(idx, "MyObject")
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myvar = myobj.add_variable(idx, "MyVariable", 6.7)
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myvar.set_writable() # Set MyVariable to be writable by clients
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# starting!
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server.start()
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try:
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count = 0
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while True:
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time.sleep(1)
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count += 0.1
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myvar.set_value(count)
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finally:
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#close connection, remove subcsriptions, etc
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server.stop()
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```
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