How do I tell if a BACnet device is online?

Updated 11 October 2026

Why test this way

A scan can fail for plenty of reasons that have nothing to do with the device. A ping proves the phone can reach the address at all. Adding the device by IP proves it is speaking BACnet. Together they tell you whether you have a network problem or a device-setup problem, and so who to call.

Step 1 — find the device's IP address

If the device has ever appeared in a scan, its IP is shown under its name. If not, check the head-end's device or network list, the as-built drawings or the controller's label, ask the controls contractor, or ask the network team to look it up in the switch's ARP or DHCP tables.

Step 2 — ping it

After a scan that finds nothing, Easy BACnet's No devices found screen has a Can you ping it? box. Type the address and tap Ping. The app pings over the same Wi-Fi or Ethernet connection it scans on, and tells you whether the device answered and whether it's on your subnet. A laptop on the same network works too: open a command prompt and type ping 10.20.30.41. You want replies, not “request timed out”.

Step 3 — add it by IP

If the ping worked, in Easy BACnet Mode open the menu (three dots) → Add device by IP…, type the address and port (47808 unless the site uses another) and tap Add. The app contacts that address directly.

• It answers. The device is online and speaking BACnet. Your scan missed it because it's on another subnet or the network is filtering scan traffic. To scan a whole remote subnet you need the site's BBMD; for this one device, you are done.
• It does not answer (No BACnet IP device answered at…). See The ping works, but Add by IP doesn't below.

The ping fails

The device can't be reached over IP, so no BACnet tool will see it until that is fixed. Common causes:

• You are on a different subnet with no route to it. Get onto the controls network and try again.
• The controller has no default gateway set, or the wrong one, so it can't reply to anything outside its own subnet. Common on controls networks that were set up flat and later routed.
• The IP is wrong, or the device picked up a new DHCP address.
• A cable is unplugged, a switch port is dead or disabled, or the unit is powered down.
• A firewall or VLAN access list blocks the path. Some networks block ping on purpose and allow BACnet, so on a managed network a failed ping is not final proof.

This is usually an IT / network conversation, unless you can see the device itself is dead.

The ping works, but Add by IP doesn't

The device is on the network but not answering BACnet at that address and port. Possible reasons:

• Wrong UDP port. Some sites run BACnet/IP on another port in the 47808–47823 range, most often 47809. Ping doesn't use ports; BACnet does. Try the add again with the right port. See what port does BACnet use?
• A firewall allows ping but blocks UDP 47808. They are separate rules and it is common to have one without the other. Network team.
• The address belongs to a router or gateway, not the device. An MS/TP controller has no IP of its own; the IP you have may be its BACnet router, which answers ping but only reaches MS/TP devices on trunks that are configured and healthy. See does Easy BACnet support MS/TP?
• BACnet/IP isn't set up on that interface. It may be disabled, bound to the controller's other Ethernet port, or not yet configured on a new gateway. Controls contractor.

Both work, but the device shows no points or no values

Communication is fine. The device is slow to enumerate, refusing some property reads, or has very little to show. See the app can't find what I'm looking for.

What to tell whoever you call

One sentence with both results saves a lot of back-and-forth: “10.20.30.41 answers a ping from the controls network, but doesn't answer BACnet on port 47808.” That rules out the cable, the power and the network path, and points at the port, a firewall rule, or the device's BACnet settings.