The device is a modular system made up of several parts. The main element is the SPM-Main Unit control unit, which manages the SPM-4Relay modules and provides connection to the eWeLink mobile app. Up to 32 SPM-4Relay modules can be connected in series to a single SPM-Main Unit via the RS-485 interface.
The system is designed for DIN rail mounting and is rated for a load of up to 20 amps per channel, that is, up to 80 amps per SPM-4Relay module. Each channel is fully independent and configured separately – there is no connection between them, and they operate autonomously.
The device lets you monitor power consumption in real time and keep full statistics. The housing has a slot for an SD card, which stores daily reports for each channel. Statistics are kept for the last 180 days. Data continues to be saved even without an internet connection. The eWeLink app has a "Current" tab – for instant consumption measurement, and a "History" tab – for viewing charts and daily reports. Although real-time data is not displayed directly, you can refresh the information by switching between tabs.
The system does not support shared access – the device cannot be shared with another eWeLink user. In addition, it cannot be transferred between different "Homes" in the app, only moved within a single one.
For each channel you can set a current threshold, and when it is exceeded the channel switches off automatically, improving the safety of the connected equipment. The device can also be used in automation scenarios – channels can act as both triggers and actuators, meaning they can switch on and off under set conditions.
If the device is installed in a room with a three-phase power supply, it lets you distribute loads across phases and control each one separately, while keeping separate statistics for each line.
Manufacturer: Sonoff
Chip model: ESP32 + GD32F
Color: White
Housing material: PC V0
Maximum current: 50 mA
Voltage: 100–240 V AC, 50/60 Hz
Wi-Fi: IEEE 802.11 b/g/n (2.4 GHz)
Ethernet: Yes
Communication protocol: SPM-Main and SPM-4Relay
RS-485: Supported
Antenna: FPC board with antenna
Security mode: WPA / WPA2
Encryption type: WEP / TKIP / AES
Operating systems: Android and iOS
Memory card: MicroSD 8 to 32 GB
Installation: DIN rail (mounting hardware included)
Connectivity: Neutral and phase
Unit connection cable length: up to 100 m
Operating temperature: –10°C ~ +40°C
Operating humidity: 5%–95%, non-condensing
Operating altitude: less than 2000 m
Brand country: China
