The Alledio MR5 is a compact DIN‑rail 5‑channel relay extender for RS485 Modbus building automation networks. Designed to expand Alledio Room Units / Alledio Room Controllers, it is also usable as a standalone Modbus relay module, MR5 adds reliable switching for fan coil units, valves, lighting circuits, fans, and motorized curtains/blinds, etc.
The 5‑Channel Modbus Relay Extender is powered from 230 V AC and provides five relay outputs (up to 5 A per contact, with a 5 A total limit through the shared common terminal).
Three application modes simplify integration:
- Fan Coil mode (3‑speed AC fan with fan-speed interlocking + heating/cooling ON/OFF valves,
- Standalone Relay mode (five freely usable relays), and
- Curtain/Shading mode (up to two drives with safe open/close interlocking).
Commissioning is done directly on the device via LED + button for Modbus address presets and factory reset.
It is also well-suited for OEM integration, offering a flexible and compact relay platform that can be embedded into third-party HVAC and room automation solutions.
Applications: Commercial Buildings
The Alledio MR5 is designed to support a wide range of typical building automation scenarios in commercial environments, where flexible relay control and Modbus integration are essential.
Hotel guest-room fan coil control (FCU) — Enables full room-level HVAC control by switching a 3-speed fan and heating/cooling valves, typically integrated with a room controller and hotel BMS for energy-efficient operation.
Office / meeting-room FCU control — Provides reliable zone-based climate control in offices and conference rooms, where individual spaces require independent temperature and airflow management.
Curtain/blind automation in hospitality and offices — Controls up to two motorized curtain or blind drives with safe interlocking, supporting daylight control, glare reduction, and automated room scenes.
Room controller output expansion — Adds five additional relay outputs via Modbus when base controllers lack sufficient I/O, reducing the need for larger or more expensive controllers.
Lighting and auxiliary load control — Switches multiple lighting circuits, fans, or other electrical loads within panels, enabling centralized or distributed control strategies in commercial spaces.
Applications: Residential buildings
In residential applications, the MR5 enables compact and flexible control of HVAC, lighting, and comfort functions within apartments, houses, and smart homes.
Apartment fan coil control — Delivers complete control of residential fan coil units, handling fan speeds and heating/cooling valves for consistent comfort in each room.
Smart home relay expansion — Extends smart home systems with additional Modbus-controlled outputs, allowing flexible switching of lights, valves, or other electrical loads.
Motorized curtain and blind control — Automates two curtain or blind motors per module, enabling scene-based control such as “morning,” “night,” or “away.”
Centralized lighting control — Supports cabinet-based lighting architectures by switching multiple circuits from a single compact module integrated into the home automation system.
Utility and bathroom automation — Controls exhaust fans, towel heaters, or other small loads, enabling automation based on humidity, schedules, or occupancy signals.
Integration with Alledio Room Unit and Room Controller
This 5‑Channel Modbus Relay Extender integrates seamlessly with Alledio Room Controllers and Room Units, extending their output capacity and enabling distributed control of HVAC and room automation functions over a single Modbus network.
Product number
Product number: ALL-MR5
Modbus Relay Channel Extender Versions
| MR5 – Relay Extender | 5-Channel Modbus Relay Extender (RS485) – 5 Relays, max. 5 A per contact; max 5 A per relay extender. |
| MR3 – Relay Extender | 3-Channel Modbus Relay Extender (RS485) – 3 Relays, max. 5 A per contact; max 5 A per relay extender. |
Technical Specifications for Alledio MR5 – 5‑Channel Modbus Relay Extender (RS485)
| Power Supply | 230 V AC |
| Power consumption | ~230 V, 3.5 VA (≈15 mA) |
| Outputs | 5 Relays, max. 5 A per contact, although each relay contact is rated for up to 5 A, the combined current through the shared common terminal is limited to 5 A maximum. |
| Communication | RS485 Modbus |
| LED light | Indication of device Heart Beat, indication of Modbus Address, indication of Setup mode. |
| Button | For Modbus Address setting (default 1) and for Factory Reset |
| Communication Cable | Twisted pair with drain wire and foil wrap or equivalent. Must be suitable for RS485 Standard. |
| Ingress Protection | IP30 |
| Ambient condition | From -40 °C to +80 °C, max. 85% rH non-condensing |
| Product dimensions | 81 mm × 44 mm × 34 mm (L × W × H) |
| Product weight | ~100 g |
| Standard | CE, RoHs, WEEE |
| Housing Material | ABS (flame resistant) |
| Country of origin | Slovenia, EU |
| Warranty | 1 year |
Datasheet ALL-MR5 – 5‑Channel Modbus Relay Extender (RS485)
Alledio by Andivi
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