Docs

Connecting

Shared server

opc.tcp://opcua-sendbox.electroman.by:4840/electroman/

Personal servers

ports 4841–5000

Security

None (anonymous login) и Basic256Sha256 (Sign/SignAndEncrypt): user and password sendbox/sendbox

Namespace

urn:electroman:opcua-sendbox (ns=2)

Nodes

Objects/SendBox/Tags/*, Objects/SendBox/Alarms/*

UaExpert

Add Server → Custom Discovery → paste the address, policy None, Anonymous (or Basic256Sha256, Sign/SignAndEncrypt, Username with sendbox/sendbox). Events: Document → Add → Event View, drag the Server node; alarms — Alarms & Conditions View.

ModbusToolkit

OPC UA tab: paste the address, security None (or Basic256Sha256 with login sendbox), Connect. History is on the History page, events on Events → subscribe to SendBox or Server.

Python (asyncua)

import asyncio
from asyncua import Client, ua

async def main():
    async with Client("opc.tcp://opcua-sendbox.electroman.by:4840/electroman/") as client:
        sine = client.get_node("ns=2;s=Tags.Sine")
        print("Sine =", await sine.read_value())

asyncio.run(main())

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Python (asyncua): subscription with reconnection

auto_reconnect=True: on connection loss the client reconnects and restores subscriptions on its own. UaExpert also restores subscriptions automatically, and the open62541 (C/C++) library has session and subscription recovery built in.

import asyncio
from asyncua import Client

class Handler:
    def datachange_notification(self, node, value, data):
        print(node, "=", value)

async def main():
    # auto_reconnect=True: при обрыве клиент переподключается
    # и восстанавливает подписки сам
    async with Client("opc.tcp://opcua-sendbox.electroman.by:4840/electroman/", auto_reconnect=True) as client:
        node = client.get_node("ns=2;s=Tags.Sine")
        subscription = await client.create_subscription(500, Handler())
        await subscription.subscribe_data_change(node)
        while True:
            await asyncio.sleep(3600)

asyncio.run(main())

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REST API

KEY=$(curl -s -X POST http://opcua-sendbox.electroman.by/api/keys | jq -r .key)
curl -s -X POST -H "X-API-Key: $KEY" http://opcua-sendbox.electroman.by/api/sessions

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What the server does

• Double, Float, Int16/32, UInt16/32 and Boolean tags with generators: sine, sawtooth, triangle, meander, counter, noise, random walk, steps, your own point profile and more.
• Writes to constant tags marked as writable.
• HistoryRead Raw: the last 1000 values of every tag.
• ExclusiveLimitAlarmType and AlarmConditionType alarms: threshold with deadband, periodic, manual; ConditionRefresh is supported.

Limits

• Sessions: 2 per key, 4 per IP, 50 in total.
• Up to 100 tags and 20 alarms per session.
• Acknowledge and Confirm are not supported: an alarm is treated as acknowledged at once. Events carry no LimitState.
• The server certificate is self-signed: on a Basic256Sha256 connection the client will ask you to trust it.

Source code

The server is open source: you can run your own copy on a local network.

git clone https://github.com/StarLeG/opcua-sendbox.git

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