How to read specific BACnet object without discover and broadcast?

Hi all,

Sorry if my question could seems strange (how I'm using BACnet) but I did not found on the documentation how to read BACnet objects with Unicast pacquet.

I have to read 2 objects present_value from 2 devices that are not on the same subnet than my Ignition server. There is no BBMD.

I can ping devices, I can use Yabe or BACeye on the server to read object but how should i setup my tags on Ignition please?

Of course, my devices on OPC UA device are uninitialized cause the "who-is" pacquet never receive "i-am" answer.

I tried to create a tag with the correct BACnet mapping but I get an Error_Configuration.

Did the Ignition BACnet driver only support discover/broadcast for BACnet ?

Thanks for your help.

I'm pretty sure this is required by Ignition to reach other BACnet subnets.

Yes in case of UDP (who-is, COV subscription, etc... ) => All that make BACnet a nice protocol.

It seems that BACnet driver is based on UDP.
Do you know if there is a way to run TCP request. I'm seeing your name very often here, how did you managed BACnet before the dedicated driver on Ignition ?

Thx.

I have not used BACnet myself. I just pay attention to others' comments here on the topic.

Okidoki :slight_smile:

Thanks for your help

@Kevin.Herron would perhaps be the man to clarify, think he did the bulk of the development of the IA BacNet driver.

A search of the forum will show others who have used it a lot (as end users).

Most of the BACnet comms are unicast, but you won't be able to do anything until the driver is successfully initialized.

"Initialization" is basically just exchanging who-Is and i-Am messages, plus some additional messages to read the object/property lists after that.

The who-Is is sent both via broadcast and unicast directly to the configured remote address. The i-Am response can come back via either, but it has to come back somehow.

No, BACnet/IP is UDP based.

Hello @Kevin.Herron;
Thanks for this clarification.

Sorry for the delay, vacations + covid ;(

I assume that the unicast packet are sent over TCP with the defined BACNet port number isn't it ?

Thx,

Martial