# CSS Diagnostics: EPICS PV Tree

The idea for this is based on the SNS "Alarm Annunciator", a Mac OS X application that monitors the alarm severity of EPICS PVs and provides a spoken message, implemented by Curtis Dunn and Tom Pelaia.

It also provides a record link hierarchy, because SNS alarm PVs are often based on calc records which summarize or conditionalize several input PVs. It is interesting to know which "original" PV caused an alarm, and the alarm annunciator offers a tree view that simply follows the calc record input links.

Thinking that this type of online link hierarchy browser might be of general use, this CSS plugin was created.

- It only requires an EPICS record name, no additional configuration or relational database, to display the current link hierarchy.
- It is of course limited to EPICS PVs that refer to records, it will not work with PVs provided by a portable ChannelAccess server or other control systems.
- Its link resolver is limited to build-in functionality, it does not parse configuration files.