Your first read

Outcome: read one known property from one authorized BACnet/IP device. You will not write to the device or change its configuration.

The examples use 192.168.1.100, device instance 1234, and analog input 1. Replace these example identifiers with values from your own lab or site. Analog input 1 is not guaranteed to exist on every device.

No known controller yet? Start with the local lab instead. This guide is for a specific device on a network you are authorized to use.

1. Check the local tool

bacnet --version
bacnet --help

Confirm that you are using the intended binary. These guides target v0.11.0; a newer or source-built version may have different options.

2. Confirm one known target

A directed Who-Is keeps the first discovery bounded to the address you supply:

bacnet discover --target 192.168.1.100 --wait 3

Look for an I-Am response and record the device instance. The displayed device count and values depend on your network; this guide does not promise that a particular controller is present.

If you already know the device identity and object list, a direct property read can be useful even when discovery does not return a response. No discovery response is not proof that no device exists.

3. Read the device name

Use the device instance returned by your target, not the example 1234:

bacnet read 192.168.1.100 device:1234 object-name

A property response tells you more than a ping: the BACnet request reached a responding endpoint, and that endpoint answered the selected object/property request.

4. Read a known point

bacnet read 192.168.1.100 ai:1 pv
bacnet readm 192.168.1.100 ai:1 pv,units,object-name

ai:1 means analog input instance 1. pv means present-value. Read units and object name before attaching engineering meaning to a number. A value such as 72.5 alone is not a universal indication of temperature or a particular unit system.

For a script-friendly response:

bacnet --json read 192.168.1.100 ai:1 pv

The CLI also chooses JSON when output is piped. Explicit --json makes intent visible. Inspect the actual output before treating it as a long-term schema contract.

If the read fails

Observation	First thing to check
No I-Am response	Target address, interface, firewall, transport, and discovery scope
Address already in use	Another local BACnet tool is using the same socket
Unknown object	The selected object instance exists on a different device, or does not exist
Unknown property	The property is not supported on this particular object
Timeout on a large request	Try a single property before investigating APDU size or segmentation

Follow the troubleshooting guide rather than increasing every timeout or repeatedly broadcasting across the network.

Understand addresses before scripting

--port selects the local BACnet UDP port; a target such as 192.168.1.100:47809 specifies a remote port. They are different settings.

A standalone bacnet discover process does not establish a documented persistent discovery cache for a later process. Use explicit IP/port targets for one-shot commands. In the interactive shell, discovery and subsequent commands can share the session cache.

Continue

Configure the network deliberately, automate the read in Python, or learn about subscriptions. Keep writes separate until you have a reviewed operational procedure.

Sources and release scope

These instructions target v0.11.0. Source review is not a claim of hardware qualification.

CLI guide · CLI argument definitions · One-shot target resolution.