# How to read specific BACnet object without discover and broadcast? **URL:** \ **Category:** Ignition\ **Created:** [December 27, 2023, 11:33am UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540 "2023-12-27T11:33:19Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Martial\_Wilbert](https://avatars.discourse-cdn.com/v4/letter/m/3ab097/32.png) [@Martial\_Wilbert](https://forum.inductiveautomation.com/u/Martial_Wilbert)\ **Post date:** [December 27, 2023, 11:33am UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/1 "2023-12-27T11:33:19Z")
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. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [December 27, 2023, 12:08pm UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/2 "2023-12-27T12:08:50Z")
> [@Martial\_Wilbert](#): > > There is no BBMD. I'm pretty sure this is required by Ignition to reach other BACnet subnets. ---
**Author:** ![Martial\_Wilbert](https://avatars.discourse-cdn.com/v4/letter/m/3ab097/32.png) [@Martial\_Wilbert](https://forum.inductiveautomation.com/u/Martial_Wilbert)\ **Post date:** [December 27, 2023, 1:31pm UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/3 "2023-12-27T13:31:14Z")
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. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [December 27, 2023, 2:14pm UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/4 "2023-12-27T14:14:45Z")
I have not used BACnet myself. I just pay attention to others' comments here on the topic. ---
**Author:** ![Martial\_Wilbert](https://avatars.discourse-cdn.com/v4/letter/m/3ab097/32.png) [@Martial\_Wilbert](https://forum.inductiveautomation.com/u/Martial_Wilbert)\ **Post date:** [December 27, 2023, 2:18pm UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/5 "2023-12-27T14:18:21Z")
Okidoki 🙂 Thanks for your help ---
**Author:** ![Matrix\_Engineering](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/matrix_engineering/32/19781_2.png) [@Matrix\_Engineering](https://forum.inductiveautomation.com/u/Matrix_Engineering)\ **Post date:** [December 27, 2023, 11:39pm UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/6 "2023-12-27T23:39:00Z")
@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). ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 27, 2023, 11:52pm UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/7 "2023-12-27T23:52:53Z")
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. > [@Martial\_Wilbert](#): > > It seems that BACnet driver is based on UDP. > Do you know if there is a way to run TCP request. No, BACnet/IP is UDP based. ---
**Author:** ![Martial\_Wilbert](https://avatars.discourse-cdn.com/v4/letter/m/3ab097/32.png) [@Martial\_Wilbert](https://forum.inductiveautomation.com/u/Martial_Wilbert)\ **Post date:** [January 18, 2024, 9:25am UTC](https://forum.inductiveautomation.com/t/how-to-read-specific-bacnet-object-without-discover-and-broadcast/83540/8 "2024-01-18T09:25:59Z")
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