# Definition

> The structure of a process, changed only when the process itself changes: the Channels, Metadata, Automation, Productivity and Printers screens, and the one shape all five share.

**Definition** is the first of a model's four groups on the [Process](process) page: the structure of the process, which changes only when the process itself changes. It holds five rows, in the order a bench is built: **Channels** (what the model measures and commands), **Metadata** (what a run stamps), **Automation** (what moves a station with nobody pressing a button), **Productivity** (what it produces) and **Printers** (where its output comes out). Every screen shows every unit of the model at once, so a bench of four stations is configured where the four are compared.

The group is drawn for Look at models, Run procedures and Manage process; a role at the Edit recipes & evaluations level without Manage is handed each model reduced to its Setup branch and does not see it. Only Manage process edits anything here.

## In this group {#in-this-group}

| Screen | What it configures |
| --- | --- |
| [Channels](process-channels) | The abstract channels every artifact of the model references, and the source and alias each unit binds behind them. |
| [Metadata](process-metadata) | The catalogue of fields a run captures at Start, the sequential identifiers, and each unit's code and counter states. |
| [Automation](process-automation) | The external stop the model follows, the signal each unit observes, and the PLC-facing automation that selects and drives a procedure. |
| [Productivity](process-productivity) | The rolling period the figures are read over and the named quantities the outputs are grouped into. |
| [Printers](process-printers) | The four printer queues (a label or a report, at Start or at Completion) every unit prints through. |

## The group page {#the-group-page}

Selecting **Definition** opens its page: "The structure of this process: the stations it runs on, what it measures, what a run stamps, what moves a station on its own, what it produces and where it prints. It changes when the process changes." One **Contents** card, "What this group holds. Click one to jump straight to it.", holds five tiles: Channels and Metadata with their counts, Automation, Productivity and Printers by name. The page has no bar and edits nothing.

The units themselves are not a row of this group: they are declared on the model's own page (see [Units](process-units)), and every screen below links there through its **Manage units** button.

## The one shape of the five screens {#the-one-shape-of-the-five-screens}

Every Definition screen is two boxed areas on the left and one settings column on the right.

| Part | What it holds |
| --- | --- |
| **Model definition** (the top area) | The model's own declaration as a table: the channels, the metadata catalogue, the External stop row, the named quantities under the rolling period fields, the four printer slots. Its head carries the one line saying what the table holds and the verbs that act on that table: the **+** that grows it (**Channel**, **Field**, **Quantity**) or, on Printers, **Refresh queues**. |
| **Per unit** (the bottom area) | The list of the model's units, in their own order, each row saying what this screen is about for that unit: coverage, code and counters, interlock signal and automation, period and quantities, queues. Its head carries **Manage units** ("Where the model's units are declared, named and removed."), which opens the model's page. |
| **Settings** (the right column) | The one row picked on the screen, in full. The head says the fixed word **Settings** and, under it, where the row came from and which it is: "Channels · Ch1 · Setpoint", "Metadata · Serial number", "Automation · External stop", "Productivity · Total", "Printers · Label at start", or "Units · Unit 1". |

Exactly one row of the whole screen is marked. Picking a row of the top table clears the picked unit; picking a unit clears the top row. With nothing picked the column shows its prompt, "Select a channel above, or a unit below, and everything it is configured with opens here." (each screen names its own halves). The unit picked below is the page's, shared by all five screens and by the model's own page, so moving between screens stays on the bench in hand; nothing is picked until you click a row.

The divider between the two areas and the divider before the column both drag and both take the arrow keys ("Drag or use the arrow keys to resize"), and each screen remembers its own sizes in this window's profile. Each area scrolls its own body under its head, so a long table never takes the other half with it.

The header of every screen carries its pills: the number of channels or fields, the number of units, and on Productivity and Printers how many units are on their own ("All on the model default", "1 of 3 on their own").

## What every screen shares in behaviour {#what-every-screen-shares-in-behaviour}

- **Autosave.** Every cell and field writes through to the model as you commit it: a combo box, a radio or a checkbox when changed, a text field when you leave it. A refused write puts the value back, and the reason lands in the action feed.
- **The picked unit** is the page's, one for the model (see [Units](process-units#one-picked-unit-across-the-model)).
- **A missing answer wears the caution ink only where it matters**: a unit short of bindings, a blank code where a sequential field composes it, a unit without a stop signal while the model observes one, a quantity without sources, an empty queue a command of the model prints through.
- **Safe renames.** Names that are addresses (a channel, a metadata field) commit through the same coordinated rename as a model or a unit: the line under the field previews how many locations read the address, and the commit rewrites them or refuses a collision.

## Permissions and locks {#permissions-and-locks}

| Situation | What happens |
| --- | --- |
| A role without Manage process | The screens are drawn and read-only; the create verbs are not drawn; the cards that carry a gate of their own say so ("Editing automation needs the “Manage process” permission.", "Changing printer queues needs the “Manage process” permission and an editable station."). |
| A unit of any model owned by a run operation | The whole page is held inert under the "Engineering locked" banner; the **+** verbs grey with "Configuration is locked while a Unit is running.". |
| The runtime stopped | Every write refuses as "Runtime stopped". |
| The picked unit busy, or with a latched interlock | Its interlock source and polarity, and the model's External stop switch and default signal, stay fixed on top of the boundary above. |

## What this group does not do {#what-this-group-does-not-do}

- It adds and removes no unit: that is the Units table on the model's page.
- It composes no run: datalogs, recipes, evaluations, occurrences, actions and procedures are [Setup](process-setup).
- It draws nothing: panels and dashboards are [Visualization](process-visualization).
- It starts nothing: a run is started under [Operate](process-operate).