Applying the Readmode to single objects

Devices from various vendors claim support for Change-of-Value, but not for all objects in a device. In this is the case trying to apply COV to all objects fails. Knowing which objects support COV (taken from the device manual or from other sources like the PICS = Protocol Implementation Conformance Statement document) allows to setup a COV access to those objects supporting this feature.

Example: Object AV:2 is requested using Readmode COVC (Confirmed COV).

Actual_Flow_Rate_feedback : FB_BACnetRM_AV := (Client:=Client,nObjectInstance:=2,eReadMode:=E_BACnet_CommMode.eCovC );
Applying the Readmode to single objects 1:

No fallback procedure is provided in case the peer device runs out of memory and is unable to accept further COV subscriptions. In this case the FB will enter an error state. In case you are uncertain, use RP/RPM polling instead of COV.