Help Reading a BACnet network

[mirkobog6]

Hello,
I am trying to read from a BACnet network configured on my localhost using the BAC0 library in Python. Below is the code I am using to send a general discovery request. However, every time I run it, no devices are discovered. This is confusing, as I have a BACnet network running and can test it using YABE.

What could be causing this issue, and how can I modify my code to ensure it works for discovering devices on any BACnet network?

Thank you for your help!

**Library:**

import BAC0
import socket
import asyncio


# Retrieving the IP address from the host PC
hostname = socket.gethostname()
host_ip = socket.gethostbyname(hostname)  # Get the corresponding IP address



async def start_bacnet_server():
    """
    Initialize the BACnet server and periodically update object values.
    """
    try:
        # Start BACnet on a specific IP and port
        device1 = BAC0.start(ip=host_ip, port=47811, deviceId=1112)

        print("BACnet started. Discovering devices...")

        # Discover devices (this may take some time)
        device1.discover(networks='known')
        # Wait a few seconds to allow device discovery to complete
        await asyncio.sleep(3)

        # Get the discovered devices
        devices = await device1.devices
        print(f"Discovered devices: {devices}")

    except Exception as e:
        print(f"Error: {e}")

    finally:
        print("Shutting down BACnet server.")

**Entry point**
if __name__ == "__main__":
    asyncio.run(start_bacnet_server())

[ChristianTremblay]

Doing test with your code here, I get a wrong subnet mask when providing only the IP. It defaults to /24 but if like me, you are using something else... it fails to send broadcast messages.

I also suggest that you use await device1._discover() which will call the aysnc version of discover that you can await so youi don't need to rely on a sleep.

Also, I really like to use async with which deals with the disconnection.

import BAC0
import socket
import asyncio


# Retrieving the IP address from the host PC
hostname = socket.gethostname()
host_ip = socket.gethostbyname(hostname)  # Get the corresponding IP address
print(host_ip)


async def start_bacnet_server():
    """
    Initialize the BACnet server and periodically update object values.
    """
    async with BAC0.start(ip=host_ip, port=47811, deviceId=1112) as device1:
        # Start BACnet on a specific IP and port
        #device1 = BAC0.start(ip=host_ip, port=47811, deviceId=1112)

        print("BACnet started. Discovering devices...")

        # Discover devices (this may take some time)
        await device1._discover()
        # Wait a few seconds to allow device discovery to complete
        #await asyncio.sleep(3)

        # Get the discovered devices
        devices = device1.discoveredDevices
        print(f"Discovered devices: {devices}")

        print("Pretty")
        await device1.devices

if __name__ == "__main__":
    asyncio.run(start_bacnet_server())

[ohshazbot]

Stumbling across this now as I work to upgrade to the new version- is _discover() the preferred way to be able to track the status of the discover task? I feels weird to be accessing protected members like this. Or has a more appropriate way been added since this question?

[ChristianTremblay]

This is mostly due to my non-experience with async code. I converted synchronous BAC0 and at the time, I was under the impression that I should try to keep some sync command line that would not require to constantly write "await"... So I created async function using _myfunction and synchronous myfunction that was calling _myfunction as a task.

Now that I worked with async a little more, I don't really care writing await... but this initial decision will haunt me for a while...