For various reasons it is sometimes necessary to change a b3's mac ID.
For example, a b3 that is removed from a site and will later be used at a different site needs to have its mac id reset to factory default to avoid the possibility of introducing a duplicate mac id.
To set the MAC ID to factory default you need BACnet Service Tool version 1.110004 (not yet released) or a beta version provided by PSS
Tested working on beta version 1.119903
BACnet Service Tool
If the b3 has previously been assigned a valid mac id then proceed to step #1.
If the b3 has factory default slave mac id then see CHANGING MAC ID ON A BRAND NEW B3 FROM THE FACTORY below
- Make sure the b3 is disconnected from the MSTP network then connect the RoamIO2 directly to the b3 using the service port.
- Launch the BACnet Service Tool and de-select the 'By Networks' and 'BACnet only' menu options in the view menu.
- Click the green icon to make the RoamIO2 sync to the baud rate of the b3 and discover it.
- In the 'Tools' menu select 'Set Offline B3 Mac Id' as shown below.
- In the 'Modify MAC Id' window enter the b3's serial number and the new mac id to be set then click Apply. (NOTE: To set the MAC ID to factory default enter 172, DO NOT USE ZERO)
To set the MAC Id to factory default you need BACnet Service Tool version 1.110004 (not yet released) or a beta version provided by PSS (
- A feedback message 'Success! will be returned if the MAC id was changed EXCEPT when setting the MAC Id to factory default (172)
- NOTE: When setting the MAC Id to factory default you will NOT get SUCCESS feedback, this is because the default id of 172 is a slave id (chosen because in hex it is AC for Andover Controls). Slave Ids are not allowed to initiate communication on the MSTP network. So, as a result of that, the b3 is unable to report to the RoamIO2 that the id was successfully changed. A visual sign that the ID was changed to 172 is that the TD led on the b3's RS485 port will shut off.
- Disconnect and re-connect to have the RoamIO2 communicate with the b3 using the new MAC id (unless you changed it to the factory default of 172).
CHANGING MAC ID ON A BRAND NEW B3 FROM THE FACTORY
The RoamIO2 can also be used to assign a mac id to a brand new b3 which has factory default mac id of 0xAC (172 decimal) but the steps are a little different.
In order for a RoamIO2 to be able to send communication packets to the b3, it first has to sync up with the baud rate of the b3, it does it by listening and analyzing the packets sent by the b3 until it is able to determine the baud rate. As mentioned before, the factory default mac id of a b3 is slave id 172 which prohibits the b3s from sending out packets and makes it impossible for the RoamIO2 to determine the baud rate.
There are several ways to work around the baud rate issue...
1. Set the baud rate manually.
- Click on the green icon to attempt connect the RoamIO2 to the b3.
- You will get an error that the baud rate could not be determined, click YES to proceed anyway
- From the 'Tools' menu select 'Set B3 Baud Rate' and set the baud rate to what you believe the last baud rate was for the b3. (The factory default baud rate is 19200)
- You should now be able to set the mac id per the steps above.
You may have to try all the baud rates until you find the one the b3 is operating at.