Description
The SONOFF SPM-Main is the central control and communication gateway of the SONOFF Smart Power Management system, designed to deliver reliable, scalable, and intelligent energy management. It connects to up to 32 SPM-4Relay modules through RS-485 communication, enabling centralized control of large electrical installations from a single platform. Through the eWeLink app and cloud system, users can remotely control circuits, monitor real-time power consumption, store historical energy data, and set overload protection rules to enhance safety and efficiency.
Built for commercial, industrial, and residential projects, the SPM-Main supports professional energy management scenarios such as factories, offices, apartment buildings, and data centers. Its robust design ensures stable communication, accurate monitoring, and long-term reliability, while advanced data analysis helps optimize electricity usage, reduce costs, and prevent electrical risks. With centralized management, flexible expansion, and smart automation capabilities, the SONOFF SPM-Main forms the backbone of a powerful and professional smart power management solution.
Key Features
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Central Gateway for Power Management
Controls and communicates with up to 32 SPM-4Relay modules via RS-485, allowing management of up to 128 channels.
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Ethernet & Wi-Fi Connectivity
Supports both wired (RJ45) and wireless (Wi-Fi 2.4GHz) internet connections for stable cloud access.
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Real-time Energy Monitoring
When paired with SPM-4Relay, it collects voltage, current, power, and energy consumption data from each channel.
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Local Data Storage
Supports microSD card (up to 256GB) to securely store historical energy data—no data loss even if disconnected from the internet.
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Overload & Short-Circuit Protection
Sends alerts and can automatically shut down circuits to protect devices and wiring.
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Remote Control & Cloud Management
Manage all relay modules, view reports, and automate circuits using the eWeLink app or web dashboard.
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DIN Rail Industrial Design
Mounts neatly inside electrical control cabinets or distribution boxes.
Technical Specifications
| Specification |
Details |
| Model |
SONOFF SPM-Main |
| Communication |
RS-485 to SPM-4Relay (Max 32 Modules / 128 Channels) |
| Network |
Wi-Fi IEEE 802.11 b/g/n (2.4 GHz), RJ45 Ethernet |
| Power Supply |
100–240V AC, 50/60 Hz |
| Data Storage |
microSD Card (Max 256GB) |
| Compatible Module |
SONOFF SPM-4Relay |
| App Support |
eWeLink (iOS / Android) |
| Protection Features |
Overload, Short-Circuit Alerts |
| Installation |
DIN Rail Mount |
| Operating Temperature |
-10°C to +40°C |
| Material |
Flame-retardant PC V0 |
| Dimensions |
143 × 90 × 66 mm |
Why Choose SONOFF SPM-Main?
Central hub for professional energy management systems
Controls up to 128 relay channels when paired with SPM-4Relay
Ethernet + Wi-Fi connectivity for stable remote access
Energy monitoring, automation, and SD card data backup
Ideal for smart buildings, apartments, offices, factories, vending machines, and commercial setups
