Issue
Managing the address table in a Lonworks device
Product Line
EcoStruxure Building Operation, TAC IA Series, TAC Vista
Environment
- I/A Series MNL
- TAC Xenta
- Third-party LON devices
- Building Operation Automation Server
Cause
A LonWorks device contains an Address Table which will hold a maximum of 15 addresses. Once this table is full, all bindings will only be able to use the broadcast setting which is not desirable.
A Xenta 200,300 or 400 controller will have its first 2 address tables used with TAG 0 and TAG 1 binding. This leaves only 13 addresses for user bindings not the 15 addresses like other LonWorks devices.
Resolution
When you create a binding in LonWorks, you decide its behavior by selecting a binding profile. You either select a binding profile, or you use the default profile.
There are basically three types of binding profiles:
- Acknowledged profiles
- Unacknowledged profiles
- Broadcast profiles
Using an Acknowledged profile will consume one of the 15 available address table addresses on both the sending and the receiving device. The Unacknowledged profiles will only use one Address on the sending device's address table. Broadcast binds do not use an address but are not recommended.
Use an acknowledged binding profile when the sending device should receive an acknowledgment from the receiving device indicating that the value of the bound variable was successfully sent.
| Binding profile | Transmit timer | Retry count |
| Acknowledged Profile | 96 ms | 3 |
| Acknowledged, Tx tmr 256, 3 retries | 256 ms | 3 |
| Acknowledged, Tx tmr 256, 5 retries | 256 ms | 5 |
| Acknowledged, Tx tmr 1024, 5 retries | 1024 ms | 5 |
Be careful of creating large, acknowledged fan-out bindings because they generate a lot of traffic, especially if the device of one of the recipients is offline.
Use an unacknowledged binding profile when the sending device should not receive an acknowledgment from the receiving device. Use this type when the value being sent is not critical and is of low importance to the control logic.
| Binding profile | Repeat timer | Repeat count |
| Unacknowledged Profile | 0 | |
| Unacknowledged Repeated Profile | 48 ms | 3 |
| Unacknowledged Repeated, 5 repeats | 48 ms | 5 |
Use a broadcast profile when you do not want to use up an entry in the address table. The device address table has 15 available entries for bindings but the first entry is a reserved broadcast entry that all broadcast bindings can share.
| Binding profile | Repeat timer | Repeat count |
| Broadcast Profile | 0 | |
| Broadcast Profile, 5 repeats | 48 ms | 5 |
If no binding profile is selected, a default profile is used:
- Point-to-point bindings use the Acknowledged profile as default.
- Fan-out bindings use the Unacknowledged Repeated profile as default.
- Building Operation uses the broadcast profile as default when the device address table has run out of entries.
If a point-to-point binding is changed to a fan-out binding, the binding profile is automatically updated to an Unacknowledged Repeated profile.
If a fan-out binding is changed to a point-to-point binding, the binding profile is automatically updated to an Acknowledged profile.
