Is there anyway to get and put several OPCUA nodes in asynchronous way?

[heritopo]

Hello,
I'm a beginner user here.
I have an issue regarding retrieve OPCUA values and return them in json format.
Currently, I have a script like this which only take a value in a time. I also give a small explaination regarding the script with "#".

import requests
import json
import pandas
from opcua import Client
import time

'Get' command to download the desired submodel

resp_get = requests.get(
'http://localhost:51310/aas/RobotStation/submodels/EnergyManagement/elements/rActivePowerTotal_Robot')

'Get' command response

response = {200: 'Sucessful',
204: 'No Content',
301: 'Moved Permenantly',
400: 'Bad Request',
401: 'Unauthorized',
403: 'Forbidden',
404: 'Not Found',
500: 'Internal Server Error'}

response_code_get = resp_get.status_code
print('The "Get" command response is: {}'.format(response[response_code_get]))

Saving the submodel as a json format

submodel_get = resp_get.json()

with open('AAS.json', 'w') as outfile:
json.dump(submodel_get, outfile)
payload=submodel_get["elem"]

#Reading OPCUA data

while True:
SERVER_ADDRESS = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
NODE_ADDRESS = 'ns=2;i=10851'
client = Client(SERVER_ADDRESS)
client.connect()
node = client.get_node(NODE_ADDRESS) #this is 'get node' command just for 1 value
value= node.get_data_value().Value.Value
#Adding opcua data to json submode
payload["value"]= value
# 'Put' command to upload the edited submodel
resp_put = requests.put('http://localhost:51310/aas/RobotStation/submodels/EnergyManagement/elements', json=payload) #this is 'put node' command just for 1 value
# 'Put' command response
response_code_put = resp_put.status_code
print('The "Put" command response is: {}'.format(response[response_code_put]))
tick = time.time()
time.sleep(2)

#Saving the new submodel as a json file
#with open('new.json', 'w') as outfile:

json.dump(payload, outfile)`

Do you have any suggestion or idea to get and put several OPCUA nodes in asynchronous way?

[AndreasHeine]

https://reference.opcfoundation.org/

i dont think its part of the OPC UA Spec.
tbh it sounds strange what you suggest, the urls are just the namespacenames not really uasable urls for http requests

[AndreasHeine]

this is at least what opc ua spec. says about clientside nodemanagement
https://reference.opcfoundation.org/Core/docs/Part1/7.5/
https://reference.opcfoundation.org/Core/docs/Part4/5.7.1/

if you just want to read/write multiple nodes at once the client has methods for that.

[heritopo]

@AndreasHeine thank you for your guidance. i forgot to insert the SS of the result when posted it. Below is the SS of data which i got throught web browser

currently, i can read and upload only a node. I am trying to read multiple node at once

[AndreasHeine]

typically for opcua if you want to read multiple there is a list of nodeids or so in the opc ua json request (but thats guessing at this point)!

[AndreasHeine]

like in the example @GoetzGoerisch posted:
if you look at the request

{
    "ServiceId": 629,
    "Body": {
        "RequestHeader": {
            "Timestamp": "2021-12-15T09:54:24.821Z",
            "RequestHandle": 1,
            "TimeoutHint": 30000,
            "ReturnDiagnostics": 2,
            "AuthenticationToken": null
        },
        "MaxAge": 0,
        "TimestampsToReturn": 0,
        "NodesToRead": [
            {
                "NodeId": {
                    "IdType": 1,
                    "Id": "Scalar_Simulation_Double,ns=2",
                    "Namespace": 2
                },
                "AttributeId": 13
            }
        ]
    }
}

@heritopo NodesToRead is a list! just expand it ;)

[heritopo]

@AndreasHeine thanks a lot. The Example and your explanation make it clear. I will try it

[swamper123]

OPC UA itself may can handle HTTPS requests (see OPC UA HTTPS, even HTTPS UA-JSON is in the specs). Haven't seen or dealed with it so far, but in my understanding, it could be possible.

But we don't support it at the moment, just TCP binary. What is possible is to read and write data to a node. Even async (via asyncio)! Take a look in the examples.

[heritopo]

@swamper123 thank you for your support. i will take a look the example

[GoetzGoerisch]

The OPC UA REST API Demo can be found here.

[GoetzGoerisch]

@heritopo, from the technical side, I hope that @swamper123 and @AndreasHeine might have a hind?

From a standardization point of view, why do you want to read a AAS submodel from an UA server?
For robots, the OPC 40010-1 UA for Robotics is the information model to use.
For the energy monitoring. the working group is working on have an harmonized approach for all sectors soon.

[swamper123]

@GoetzGoerisch Haven't done much in that field, sorry. 😕

[heritopo]

@GoetzGoerisch thank you for your response. The submodel contain information from AASX explore which is as data storage. so we need download AAS in to server. Through OPC-UA,the value will be read and it's put in to submodel. Then the data's value can be accesed through web browser.

[heritopo]

@GoetzGoerisch i don't have any idea about OPC 40010-1 UA. do you have any reference ?

[GoetzGoerisch]

@GoetzGoerisch i don't have any idea about OPC 40010-1 UA. do you have any reference ?

Sure https://reference.opcfoundation.org/Robotics/docs/

@xenonforlife, can answer some questions.