python opc ua client 如何自动连接，不超时断线，不报警退出。

[shijiandeguanli]

大家好，
我用Python 设计一个opc ua client ,
如下程序代码1所示，
但，运行的过程中，如果OPC UA 服务器没启动，程序会发生如下的“报错信息1”
如果OPC UA服务器中途停止，程序会发生如下的“报错信息2”超时报错。

我想达到的效果是： 这个代码在运行的时候，当OPC UA服务器没启动是，在等待链接。当OPC UA停止时，也是在等待链接。不要报错。






#程序代码1
import time
from opcua import Client
from opcua import ua

client = Client("opc.tcp://WIN-G9KK36SKPQC:37800")
client.connect()


while True:
#读取变量节点
ret = client.get_node("ns=1;s=T1")
ret2 = client.get_node("ns=1;s=D2")
print(ret.get_value())
print(ret2.get_value())
time.sleep(1)

client.disconnect()


报错信息1：
Traceback (most recent call last):
File "C:\Users\Administrator\Desktop\新建文件夹\OPC测试\结合\NewTryTest 变量节点.py", line 11, in <module>
client.connect()
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\client\client.py", line 255, in connect
self.connect_socket()
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\client\client.py", line 280, in connect_socket
self.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\client\ua_client.py", line 245, in connect_socket
return self._uasocket.connect_socket(host, port)
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\client\ua_client.py", line 142, in connect_socket
sock = socket.create_connection((host, port), timeout=self.timeout)
File "D:\Program Files\Python3.6.3\lib\socket.py", line 724, in create_connection
raise err
File "D:\Program Files\Python3.6.3\lib\socket.py", line 713, in create_connection
sock.connect(sa)
ConnectionRefusedError: [WinError 10061] 由于目标计算机积极拒绝，无法连接。


报错信息2：
Traceback (most recent call last):
File "C:\Users\Administrator\Desktop\新建文件夹\OPC测试\结合\NewTryTest 变量节点.py", line 18, in <module>
print(ret.get_value())
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\common\node.py", line 153, in get_value
result = self.get_data_value()
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\common\node.py", line 162, in get_data_value
return self.get_attribute(ua.AttributeIds.Value)
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\common\node.py", line 273, in get_attribute
result = self.server.read(params)
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\client\ua_client.py", line 326, in read
data = self._uasocket.send_request(request)
File "D:\Program Files\Python3.6.3\lib\site-packages\opcua\client\ua_client.py", line 78, in send_request
data = future.result(self.timeout)
File "D:\Program Files\Python3.6.3\lib\concurrent\futures\_base.py", line 434, in result
raise TimeoutError()
concurrent.futures._base.TimeoutError

[27-_-]

楼主，我也有这个疑问，请问您把这个问题解决了吗

[神秘奢华]

你这种情况可以写一个递归，try 。。。 except 调用自身。我还遇到一种订阅的时候报错，但是连接和订阅在两个线程。报错try不到就很烦