---
title: "Library items and impact"
---

# Library items and impact

What a change to a library item of a DeltaV export reaches: module classes, composites, function block types, named sets, and phase, unit and process cell classes.

**Verification state:** modelled. On the real DeltaV 14.5.1 export: 317 library items and 1,292 uses found in about 0.6 s; the impact of every item computed in 3 ms in all; the widest item reaches 425 objects up to 3 steps away. Not seen in the running Editor; not on Windows.

## Show the impact of a change

1. Run **Show Impact of a Library Item**, or **Show Impact of a Change** on a module class or phase class in the DeltaV Plant view.
2. Pick the item. Items are sorted by reach: module classes, composites, function block types, named sets, phase classes, unit classes and process cell classes.
3. A **DeltaV Impact** tab shows what uses the item directly, then what uses those, grouped by distance, each with the item it goes through and every place it is named.

Click a name to open the text there. The tab follows the text.

A use is a `DEFINITION=`, `MODULE_CLASS=`, `CLASS=`, `SET=` or `COMMAND_SET=` naming the item, anywhere inside a statement. Each user is listed once, at the distance first reached.

## Limits

- Only the open export is read: users in other exports of the same database are not counted.
- Names used inside expressions are not counted.
- The view says what a change reaches, not what it does to each user.