https://github.com/zarethrex/opcua-cablecar
Demo of using OPCUA for control/status of simulation for a cable car
https://github.com/zarethrex/opcua-cablecar
Last synced: 7 months ago
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Demo of using OPCUA for control/status of simulation for a cable car
- Host: GitHub
- URL: https://github.com/zarethrex/opcua-cablecar
- Owner: zarethrex
- Created: 2022-06-09T22:25:25.000Z (almost 4 years ago)
- Default Branch: master
- Last Pushed: 2022-07-17T14:59:41.000Z (almost 4 years ago)
- Last Synced: 2025-09-20T19:39:03.489Z (9 months ago)
- Language: Python
- Size: 26.4 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# OPCUA Cable Car Model
A rough model of the San Francisco cable car system. The design very loosely matches how the cable cars operate and has been used as a way of demonstrating what
can be accomplished simulation wise using a mixture of OPCUA and Python asynchronosity.
## Connections
The whole simulation is orchestrated by an server class which creates an OPCUA, any asynchronous processes are assigned to this server class which then runs them.
Commands are sent to the server via a client, these commands change the state of the objects they control (i.e. the winder and the car itself).
```mermaid
graph TD;
A[Server]
B[Route]
C[Cable Car]
D[Winder]
E[Client]
C -.Status.-> A
A -.Command.-> C
B --> C
D --> B
D -.Status.-> A
A -.Command.-> D
E -.Command.-> A
```
## Install & Demonstration
Install the project using [Poetry](https://python-poetry.org), then run the CLI using the command `cablecar` under the created virtual environment:
```sh
$ python -m pip install poetry
$ poetry install
$ poetry run cablecar
INFO:CableCarSim.SimulationServer:Starting server on: opc.tcp://127.0.0.1:4080/freeopcua/server
WARNING:asyncua.server.server:Endpoints other than open requested but private key and certificate are not set.
INFO:CableCarSim.Simulation:Setting up simulation
```
Create a script for a client to send commands to the server:
```python
import asyncua.ua
import asyncua.sync
server_port = 4080
client = asyncua.sync.Client(f"opc.tcp://127.0.0.1:{server_port}/freeopcua/server")
client.connect()
# Fetch the objects node from the server
objects_node = client.get_node(
asyncua_ua.TwoByteNodeId(asyncua_ua.ObjectIds.ObjectsFolder)
)
# Retrieve the nodes for the winder and car controllers
winder_control = objects_node.get_variables()[1]
car_control = objects_node.get_variables()[-2]
# Turn on the winder for the route
winder_control.set_value("ON")
# Engage the grip control on the car
car_control.set_value("GRIP_ENGAGE")
```
Running the script will attach the cable car to the cable and move it:
```sh
INFO:CableCarSim.Winder.Powell:STATUS=Status.CLOCKWISE
INFO:CableCarSim.Winder.Powell:CONTROLLER=Controller.NONE
INFO:CableCarSim.Winder.Powell:SPEED=4.25
INFO:CableCarSim.CableCar.Car_1:GRIP_STATE=GripState.ENGAGED
INFO:CableCarSim.CableCar.Car_1:CURRENT_SPEED=0.1
INFO:CableCarSim.CableCar.Car_1:CURRENT_POSITION=0.1
INFO:CableCarSim.CableCar.Car_1:CURRENT_LOCATION=('Hyde St & North Point St', 'Hyde St & Beach St')
INFO:CableCarSim.CableCar.Car_1:CURRENT_SPEED=0.2
INFO:CableCarSim.CableCar.Car_1:CURRENT_POSITION=0.30000000000000004
...
INFO:CableCarSim.CableCar.Car_1:Reached route limit, stopping
INFO:CableCarSim.CableCar.Car_1:GRIP_STATE=GripState.RELEASED
```
```mermaid
sequenceDiagram
participant Client
participant Server
participant Powell Winder
participant Car 1
Client->>Server: Winder.Powell.CONTROLLER=ON
Server->>Powell Winder: CONTROLLER=ON
Note over Powell Winder: STATUS=CLOCKWISE
Note over Powell Winder: SPEED=4.25
Powell Winder ->> Server: CONTROLLER=NONE
Client->>Server: Car.1.CONTROLLER=GRIP_ENGAGE
Server->>Car 1: CONTROLLER=GRIP_ENGAGE
Note over Car 1: GRIP_STATE=ENGAGED
Car 1->>Server: CONTROLLER=NONE
loop while POSITION < Route Length
Car 1->>Car 1: POSITION+=SPEED*t
Car 1->>Car 1: LOCATION=(PREVIOUS, NEXT)
loop
Note over Car 1: SPEED < Winder.Powell.SPEED
Car 1->>Car 1: SPEED+=ACCELERATION*t
end
Note over Car 1: SPEED=4.25
end
Note over Car 1: SPEED=0.0
Note over Car 1: POSITION=Route Length
Note over Car 1: GRIP_STATE=RELEASED