SDM01G2X / Compact Energy Meter

Both are ultra-slim 18mm DIN-rail energy meters, but the SDM01 G2X is purpose-built for professional HEMS, PV/ESS, and EV charging integrations that demand richer local connectivity and robust Wi-Fi connection. Key differences:

• Wireless APISDM01 Combo Gen2: Tuya / Zigbee 3.0SDM01 G2X: HTTP, MQTT, UDP, WebSocket, Modbus TCP
• AntennaSDM01 Combo Gen2: InternalSDM01 G2X: External (better metal-box penetration)
• Target UserSDM01 Combo Gen2: Energy IoT Beginners / IntegratorsSDM01 G2X: Professional DIYers, PV/ESS/EVSE Manufacturer
• Smart HomeSDM01 Combo Gen2: Tuya / Home AssistantSDM01 G2X: Home Assistant, Homey

If you need rich local LAN APIs and robust Wi-Fi in a metal distribution box, the SDM01 G2X is the right choice.

The main module is powered and measures voltage through four wires on the voltage take-offs connector: X (L1), Y (L2), Z (L3), and N (Neutral). Supported system configurations at 50/60 Hz:

• 220–240 VAC phase-to-neutral
• 380–415 VAC phase-to-phase

The SDM01 G2X also supports:

• Split-phase systems (e.g., 120/240V North American residential) — use two CT channels for L1 and L2 with N as neutral reference.
• Three independent single-phase circuits — each CT monitors a separate branch circuit sharing a common neutral.

|⚠️ Note: The SDM01 G2X is not suitable for 3P3W (three-phase, no neutral) installations.

Yes. Each CT has an arrow indicating the positive (forward) power flow direction — typically pointing toward the load side. CT wires must also be connected with correct polarity: Red (+) to "+" and Black (−) to "−" on the CT connector. Reversed polarity results in negative power readings but will not damage the device.

Yes, the external antenna must be connected before powering the device. It is designed specifically to overcome Wi-Fi signal shielding caused by metal distribution boxes, which are common in European and commercial installations. The external antenna significantly improves connection stability and range compared to a PCB antenna in such environments.

|📝 The antenna connector is located on the bottom side of the main module. Ensure the antenna is routed out of the box through a cable gland or knockout hole.

The SDM01 G2X (Wi-Fi variant) supports a comprehensive set of local LAN APIs, enabling integration without any cloud dependency:

• HTTP — Pull real-time data via REST requests
• MQTT — Subscribe to live power data on a local broker
• UDP Unicast / Multicast — Ultra-low-latency broadcast for export limiting and DLB
• WebSocket — Persistent real-time data streaming
• Modbus TCP — Industry-standard wired-over-LAN protocol

Full open API documentation is provided for custom integrations with PV inverters, EV chargers, ESS, and third-party HEMS hubs.

Yes — and setup is straightforward. Install the Bituo PMD integration via HACS, and it will automatically discover the SDM01 G2X on your local network. All communication is fully local — no cloud account or cloud dependency of any kind.Three ways to add the device:

• Auto-discovery (recommended) — Once the device is on the same network as Home Assistant, it appears automatically in the Discovered integrations list. Just click Configure → Submit.
• Zeroconf scan — Trigger a manual network scan from within the integration to find devices.
• Manual IP — Enter the device's IP address directly if auto-discovery is not available on your network setup.

Once added, you get:

• All measured entities (voltage, current, power, energy, etc.) available directly in Home Assistant
• Access to the device's embedded web UI via the View button
• Full device settings control (zero energy, restart, factory reset) from the HA sidebar
• OTA firmware updates managed directly from within the integration

Yes. The SDM01 G2X uses a dual MCU + SoC architecture: the metering MCU handles all measurement functions independently, while the communication SoC (ESP32-8685) can be reflashed with custom firmware — without affecting measurement accuracy. This makes it well-suited for OEM/ODM projects and professional integrators who need custom communication stacks or proprietary protocols.

The SDM01 G2X is certified to Class 1 per IEC 61557-12. Per IEC 61557-12:2021, Table 8 — intrinsic uncertainty limits for active power and active energy (Class 1, C = 1):

• Current Range: 5%I_b ≤ I < 10%I_bPower Factor: 1 | Accuracy: ±1.5%
• Current Range: 10%I_b ≤ I ≤ I_maxPower Factor: 1 | Accuracy: ±1.0%
• Current Range: 10%I_b ≤ I < 20%I_bPower Factor: 0.5L / 0.8C | Accuracy: ±1.5%
• Current Range: 20%I_b ≤ I ≤ I_maxPower Factor: 0.5L / 0.8C | Accuracy: ±1.0%

The ±1.0% zone covers the vast majority of real-world operating conditions. The ±1.5% tolerance only applies at very light loads, which represents a small fraction of typical operating time.

|📝 Note: The standard sets no accuracy requirement below 5%I_b at PF = 1, and below 10%I_b at non-unity PF. This is consistent across all IEC 61557-12 Class 1 devices.

The SDM01 G2X captures precise RMS power data within 150ms, making it one of the fastest-reporting energy meters in its class. This rapid measurement cycle is essential for:

• Export limiting — Reacting quickly to solar generation changes to prevent grid overfeed
• Dynamic Load Balancing (DLB) — Adjusting EV charger output in real time based on available household capacity
• ESS control — Providing near-instantaneous data to battery management systems

Yes. Bi-directional measurement is a core feature of the SDM01 G2X. It simultaneously tracks imported energy (consumption from the grid) and exported energy (generation fed back to the grid), making it ideal for households and businesses with solar PV or battery storage systems.

No. If a CT is damaged or needs replacement, simply order a replacement CT of the same official Bituo Technik model — no factory recalibration is required.

We tightly control the ratio error and phase error of every CT we produce, ensuring that any officially designated Bituo Technik CT of the same model is fully interchangeable with your SDM01 G2X and will maintain Class 1 accuracy straight out of the box. This makes field maintenance and replacement straightforward, with no downtime waiting for factory service.

|📝 Note: This interchangeability guarantee applies only to official Bituo Technik designated CTs of the matching model. Third-party or non-designated CTs are not covered and may affect measurement accuracy.