Extended Trend Logs
When configuring extended logging in the BACnet application folder, these objects are not available when performing a device discovery from the AS or ES.
- prepare one AS with a BACnet point
- put a trend log on that BACnet point
- then create an Extended log for that BACnet trend log
From a second AS, the BACnet objects are available after a Device Discovery except for the Extended log object.
StruxureWare Building Operation online help for “Configuring Extended Logging for a BACnet Trend Log” states:
***Key Concept: Extended trend logs are not BACnet objects. These are StruxureWare Building Operation exclusive. The term "BACnet Extended Trend Log" does not exist and is a misnomer.
The main reason is that extended logs are not defined in the BACnet standard; they are proprietary to SmartStruxure.
Everything that is proprietary to StruxureWare Building Operation is not exposed to BACnet including graphics, script & function block programs and central IO points are not directly exposed, but have to be bound to BACnet I/O objects.
The extended log serves the purpose of expanding a log on a larger capacity server. A trend log on an AS would be more appropriate to extend on an ES. If you have a trend log in an external BACnet device (like a b3 or a 3rd party device/system) then you would want an extended log in the AS, to collect from that device (and then maybe a larger extended trend on a parent ES).
If you have a local BACnet trend log in an AS (in the BACnet interface application folder) that you want to make larger, consider increasing the buffer size property of that one log to what you need (the default size of 10 may be too small, and increasing to 1000 up to 5000 (extended log size) may be an option). That would be most interoperable with other (3rd party) BACnet clients that need access to the trend log data.