python OPCUA伺服器和客戶端開發

阿新 • • 發佈：2021-01-19

環境準備
安裝開源的OPCUA包，安裝採用pip安裝。

pip install opcua

伺服器端程式開發
主要需要修改的內容為釋出的網路地址：
127.0.0.1表示釋出為本機地址。


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

import time

from opcua import ua, Server

if __name__ == "__main__":

    # setup our server
    server = Server()
    server. 
set_endpoint("opc.tcp://127.0.0.1:4840/freeopcua/server/")

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

    # get Objects node, this is where we should put our nodes
    objects = 
 server.get_objects_node()

    # populating our address space
    myobj = objects.add_object(idx, "MyObject")
    myvar = myobj.add_variable(idx, "MyVariable", 6.7)
    myvar.set_writable()    # Set MyVariable to be writable by clients

    # starting!
    server.start()
    
    try 
:
        count = 0
        while True:
            time.sleep(1)
            count += 0.1
            myvar.set_value(count)
    finally:
        #close connection, remove subcsriptions, etc
        server.stop()

客戶端程式開發

import sys,time
sys.path.insert(0, "..")
from opcua import Client

if __name__ == "__main__":

 

    client = Client("opc.tcp://localhost:4840/freeopcua/server/")
    #client = Client("opc.tcp://127.0.0.1:4840/freeopcua/server/")
    #client = Client("opc.tcp://[email protected]:4840/freeopcua/server/") #connect using a user
    try:
        res = client.connect()

        # Client has a few methods to get proxy to UA nodes that should always be in address space such as Root or Objects
        root = client.get_root_node()
        print("Objects node is: ", root)

        # Node objects have methods to read and write node attributes as well as browse or populate address space
        print("Children of root are: ", root.get_children())

        # get a specific node knowing its node id
        #var = client.get_node(ua.NodeId(1002, 2))
        #var = client.get_node("ns=3;i=2002")
        #print(var)
        #var.get_data_value() # get value of node as a DataValue object
        #var.get_value() # get value of node as a python builtin
        #var.set_value(ua.Variant([23], ua.VariantType.Int64)) #set node value using explicit data type
        #var.set_value(3.9) # set node value using implicit data type

        # Now getting a variable node using its browse path
        while(1):
            myvar = root.get_child(["0:Objects", "2:MyObject", "2:MyVariable"])
            obj = root.get_child(["0:Objects", "2:MyObject"])
            print("myvar is: ", myvar)
            print("myobj is: ", obj)
            
            # Stacked myvar access
            print("myvar is: ", root.get_children()[0].get_children()[1].get_variables()[0].get_value())
            time.sleep(2)

    finally:
        client.disconnect()