Subscription behavior is unique to a station’s PlatformServices slots, in that property values initially load, but do not automatically update. To explicitly refresh such properties, you must invoke the “poll” action of the container for those properties.

For example, if on a Px page you bind a BoundLabel to the PowerMonitorService’s “Battery Good” slot, it will display text as “true” or “false.” However, this value does not update until the user right-clicks for the “Poll” action, which forces a fresh read.

Figure 123. Poll action on bound PlatformServices property

Links from PlatformServices (and child slots) to other station components must use a source ord “slot path”, versus “handle”. Otherwise, after a station restart or host reboot, handle-sourced links may be lost. An example link being edited to use slot path is shown in Figure 124.

Consider the “update limitation” before linking PlatformServices slots into other components that provide control logic. Linked slot values may well be outdated shortly after station startup, yet still “subscribed” and not marked as “stale.”