For those who do NOT require any interaction between Home Assistant and the programs on their ISY, providing a configuration option to exclude ISY programs from communications with HA might reduce latency, improve speed, and reduce the network communication burden on the ISY. A similar option for ISY variables, if they are not needed in Home Assistant, could also help.
For example, my ISY994i has 1080 programs and 110 devices. In my implementation, Home Assistant only needs access to the 110 devices–not the 1080 programs, yet Home Assistant logs for 24 hours include over 103,000 log entries regarding ISY programs and only 2,200 log entries regarding ISY device nodes (with debug logging set for custom_components.isy994, homeassistant.components.isy994, and pyisy).
Similarly, I currently have no need for Home Assistant to interact with my 699 ISY variables, yet Home Assistant logs include over 41,000 log entries in 24 hours related to ISY variables.
The 24-hour counts of 103,000 + 41,000 Home Assistant log entries regarding ISY elements that Home Assistant does not need to know about in my case (vs 2,200 log entries for the ISY device nodes that are needed) suggests that a lot of time and communication resources are wasted in my case.
Configuration options to give the installer of the ISY994 Integration the options of excluding ISY programs and/or variables from integration might therefore improve the speed of Home Assistant interactions with the ISY, and might benefit the ISY by reducing its network communication load.
Thanks for your consideration! And, thanks for the ISY994 Integration, which is amazing way for an ISY994i user such as myself to begin transitioning to Home Assistant!