# Control modes

Each page describes one `pumpingStation` control mode and how it uses the shared [basin model](../functional-description.md#basin-model) — specifically, how it uses the three control thresholds (`minLevel`, `startLevel`, `maxLevel`) and computes the demand it sends to the MGC.

The two **safety** thresholds (`dryRunLevel` and `overflowLevel`) are mode-independent and are enforced by the safety layer outside any mode. They never appear in a mode's policy.

## Template

Every mode page follows the same structure:

1. **At a glance** — one sentence + small fact table (inputs, output, status)
2. **Diagram** — one or more, per tier (see below)
3. **Inputs** — what signals the mode reads
4. **Threshold policy** — how it uses / adjusts `minLevel`, `startLevel`, `maxLevel`
5. **Demand formula** — pseudocode for Tier 1/2, objective function for Tier 3
6. **Edge cases** — cold start, sensor dropout, interaction with safety layer
7. **Related** — links to other modes + functional description

The three **tiers** classify modes by how dynamic the decision surface is:

| Tier | Curve | Example modes | Diagram type |
|---|---|---|---|
| **1** — static | Memoryless `demand = f(x)`; single curve | `levelbased`, `manual` | Single-curve transfer function |
| **2** — parameterised | Shape fixed, curve moves with θ(t) | `flowbased`, `pressureBased`, `percentageBased`, `powerBased` | Transfer function + parameter overlay / family |
| **3** — horizon-based | Optimisation, no fixed curve | `hybrid-optimal`, `mpc`, weather-aware | Block diagram of signal flow + scenario time-series |

## Implementation status

| Mode | Tier | Status | Page |
|---|---|---|---|
| `levelbased` | 1 | ✅ implemented | [levelbased.md](levelbased.md) |
| `manual` | 1 | ✅ implemented (via `Qd` topic) | — |
| `flowbased` | 2 | 🚧 code placeholder, template | [flowbased.md](flowbased.md) |
| `pressureBased` | 2 | 🚧 code placeholder | — |
| `percentageBased` | 2 | 🚧 code placeholder | — |
| `powerBased` | 2 | 🚧 code placeholder, template | [powerbased.md](powerbased.md) |
| `hybrid` | 3 | 🚧 code placeholder | — |
| `mpc` | 3 | 🚧 not in code yet, template | [mpc.md](mpc.md) |