Issue
- LonWorks point count recommendation for the Xenta 5/7/9xx series controllers
- What is the device limitation on the FT-10 LonWorks channel installed on a Xenta Server
Product Line
TAC Vista
Environment
- Xenta 500
- Xenta 700
- Xenta 900
Cause
The load point table can be found in Vista version Release Notes on The Exchange Download Center.
When Xenta 700 was released the Product Announcement had a table with the recommended number of LonWorks devices attached to Xenta 5/7/9xx. Below you can see a small revision of the recommendations. The list applies to devices which the applications in the Xenta 5/7/9xx are interchanging data with. Other devices that are completely handled by TAC Vista through the LTA port of Xenta 5/7/9xx are not included in this calculation. These devices will influence the LonWorks network performance in a similar way as if they were connected through a Xenta 911 and have to be considered.
Not following the design recommendations and adding too many LonWorks devices to a single channel will cause poor Xenta Server performance.
Resolution
Each device uses "load points" according to the table. As a general guideline the total "load points" on the network shall stay under 100 to get a reasonable performance. In reality the e.g. intensity of the traffic also has an influence as well as, of course, the expectations on response time.
| Type of device | Load points |
| I/O module | 5 |
| Xenta group master 280/300/401 | 20 |
| Additional Xenta 280/300/401 in the group | 2 |
| Standard LonWorks device, including Xenta 100, polled | 2 |
| Standard LonWorks device, including Xenta 100, bound | 0.75 |
Refer to The Exchange Download Center for future releases of Vista / Xenta Release Notes containing software and updated load calculations
This information is usually found in the Appendix B - Engineer Information, and look for section titled
LonWorks recommendation for the Xenta 500 and 700 series
