| Zone | One independent irrigation circuit — a group of schedules, outputs, sensors, and conditions |
| Schedule | A rule that defines when and how long a zone runs |
| Output | A physical relay or digital pin that opens/closes a solenoid valve |
| Sensor | An analog or digital input that measures a physical quantity (soil moisture, flow, etc.) |
| Condition | A logical check that must pass before a scheduled run can start |
| Scanner / IO Scanner | A remote relay or input module connected over Modbus RS-485 or direct GPIO |
| Modbus | Industrial serial communication protocol used to talk to remote IO boards over RS-485 wiring |
| Scanner Sub ID | The specific channel (relay output or digital input) on a scanner board |
| Seasonal Factor | A percentage multiplier applied to schedule duration to compensate for seasonal changes in water demand |
| NTP | Network Time Protocol — used to synchronise the device clock over the internet |
| MQTT | Lightweight messaging protocol for integrating IrrigEngine with home-automation systems (Home Assistant, Node-RED, etc.) |
| AP Mode | Access Point mode — the device creates its own WiFi hotspot when no network credentials are stored |
| Max Concurrent Zones | Hard limit on how many zones may be watering at the same time |
| NORMAL_OPEN / NORMAL_CLOSED | Describes the valve's resting state: NORMAL_OPEN valves allow flow when the relay is de-energised |
