I have a Hmi that acts as an interface for many (mostly identical) units. This is managed by a sort of "mux" where you select which unit that should be presented on the HMI. Backbone is solved by a HMI-gvl defined as reference/pointer to "unit-data", which then can be set to the individual units.

While this works for most data I still have not sorted how to solve this for the trend recordings.

One solution would be to have already "mux:ed" data values as source for the/one trend. However then the trend would contain data from different units/sources which could/will cause confusion.

If its possible to "clear" this can be mitigated. Possibly let the trend have its own "mux-selector" (ie, the hmi are focusing on unit#3 however trend data is locked on unit#5), that could also work..

Or, let each unit have its own trend recording, which is focused if the unit is "selected". Can I reach the trend recording objects programmatically (those defined in the device tree)? Ie, can I use a "reference/pointer to these trend recording objects"?

There is a field "data source" in the trend properties dialog which seems to resemble what Im looking for? But Im not sure if I can use it in some way, I cannot change anything in this field it only says <local application="">. </local>