Python OPC UA 将变量传递给 uamethod

如何解决Python OPC UA 将变量传递给 uamethod

我有一个示例，其中将方法添加到服务器空间。该示例设置为采用两个输入值并将它们相加。

代码示例

from opcua import Server,ua,uamethod,instantiate
import time
from opcua.ua import NodeId,NodeIdType

@uamethod
def add_func(self,a,b):
    print("Adding parameters:\n","\tand\t",b)
    return a + b

if __name__ == "__main__":

    # setup server
    server = Server()
    server.set_endpoint("opc.tcp://localhost:4840") #alternative: 
    server.set_endpoint("opc.tcp://0.0.0.0:4840")
    server.set_server_name("Server example")
    server.set_security_policy([ua.SecurityPolicyType.NoSecurity])
    uri = "http://example.uri.de"
    idx = server.register_namespace(uri)
    
    # get Objects node,this is where we should adress our custom stuff to
    objects = server.get_objects_node() # alternative: root_node = server.get_root_node()
    
    # add structure to the namespace (idx) below the Objects node
    myobj = objects.add_object(idx,"MyObject")

    # add variables,type can be defined by assigning a value or ua Variant Type definition
    var1 = myobj.add_variable(idx,"var1",321,ua.VariantType.Int64)
    var2 = myobj.add_variable(idx,"var2",123,ua.VariantType.Int64)

    # set variables writable for clients (e.g. UaExpert)
    var1.set_writable()
    var2.set_writable()

    # set input arguments for method
    input_arg1 = ua.Argument() # create new argument
    input_arg1.Name = "a" # name for argument
    input_arg1.DataType = ua.NodeId(ua.ObjectIds.Int64) # data type
    input_arg1.ValueRank = -1 # value rank to be treated a scalar number
    input_arg1.Description = ua.LocalizedText("First integer a") # add description text

    input_arg2 = ua.Argument()
    input_arg2.Name = "b"
    input_arg2.DataType = ua.NodeId(ua.ObjectIds.Int64)
    input_arg2.ValueRank = -1
    input_arg2.Description = ua.LocalizedText("Second integer b")

    # set output arguments
    output_arg = ua.Argument()
    output_arg.Name = "Result"
    output_arg.DataType = ua.NodeId(ua.ObjectIds.Int64)
    output_arg.ValueRank = -1
    output_arg.Description = ua.LocalizedText("Sum")

    print(var1.nodeid)
    print(var2.nodeid)

    # add method to namespace
    mymethod = myobj.add_method(idx,"MyAddFunction",add_func,[input_arg1,input_arg2],[output_arg])

    server.start()

我想做的改变是删除输入参数并在调用 MyAddFunction 时自动将 var1 和 var2 作为输入。 我使用 UaExpert 来调用这个方法。 UaExpert when calling MyAddFunction

我尝试使用它们的 NodeID 传递变量，如下所示：

mymethod = myobj.add_method(idx,[var1.nodeid,var1.nodeid],[output_arg])

并收到以下错误消息： opcua.ua.uaerrors._base.UaError: NodeId: 无法猜测 NodeId 的类型，设置 NodeIdType

创建变量的时候是不是没有定义类型？ 必须对将 var1 和 var2 作为输入参数的方法进行哪些更改？有没有办法将这些值分配给创建的输入参数（input_arg1 & input_arg2）？

先谢谢你！ 问候南多