> For the complete documentation index, see [llms.txt](https://docs.bituo-technik.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bituo-technik.com/product-document/sdm-series/sdm01-combo-gen2.md).

# SDM01 Combo Gen2

{% hint style="info" %}
**Status:** Preliminary | **Applies to:** SDM01 Gen2 Combo | **Hardware Revision:** V1.0+ | **Last Updated:** 2026-07-27
{% endhint %}

### 1.  Introduction

![](https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FAdDoZ1z6LkP8gQBjtrj0%2FSDM01G2-with-3CT_Transparent-for-Webpage.png?alt=media\&token=ef7e1e7b-4688-43ba-a841-dc498ef8360b)

The **SDM01 Combo Gen2** maintains the ultra-slim 18mm (1-module) profile for precise monitoring of three-phase or multiple single-phase circuits. Equipped with three split-core CTs, it accurately measures voltage, current, power, and energy. It supports both wired and wireless communication for flexible and seamless system integration. Its ultra-fast bi-directional power measurement makes it particularly suitable for export limiting application.

#### Product Highlights

* **Bi-directional Measurement**: Accurately monitor both imported (consumption) and exported (generation) power and energy flows.
* **Space-Saving Setup:** Features a compact 1-module width (1MW) DIN rail design, complemented by easy-to-install split-core current transformers.
* **Advanced Local Control:** Supports extensive local APIs, making it the perfect fit for Home Energy Management Systems (HEMS), dynamic load balancing (DLB), and zero-export limiting.
* **Real-time Monitoring**: Delivers live tracking of critical electrical parameters, including voltage, current, and active power.
* **Flexible Integration:** Offers seamless connectivity through multiple protocols like Wi-Fi, Zigbee, and Modbus to suit diverse system architectures.
* **Modbus Support**: Hybrid WiFi/Zigbee + Modbus variants are available for industrial installations.

#### Typical Application

* Home energy management systems (HEMS)
* energy management systems (EMS) for small business 
* Energy management systems (EMS) for buildings, Infrastructure, and Industry
* Dynamic load balancing (DLB) for electrical vehicle charging
* Export limitation for renewable power generation

***

### 2. Part Description

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2F20txVy6ZjQ9G31eh9yjg%2Fimage.png?alt=media&amp;token=a4a6c2dc-c760-435d-8886-4961161736f1" alt=""><figcaption></figcaption></figure>

<table data-header-hidden><thead><tr><th width="84.5555419921875">#</th><th width="257.666748046875">Element</th><th>Description</th></tr></thead><tbody><tr><td>1</td><td>Connector for voltage take-offs connection</td><td>The monitor is powered by AC power supply and measures voltage through four cables: X, Y, Z, and N</td></tr><tr><td>2</td><td>Connector for current transformer connection</td><td>The Red (+) and Black (-) wires of CT(X), CT(Y), and CT(Z) must match the corresponding polarity of the connector.</td></tr><tr><td>3</td><td>Connector for RS485 communication</td><td>For Modbus RTU communication</td></tr><tr><td>4</td><td>Reset button</td><td>Press and hold for 3–5 seconds to enter pairing mode.</td></tr><tr><td>5</td><td>Status LED (ACT)</td><td>Indicates device operation and network status through different flashing patterns.</td></tr><tr><td>6</td><td>Alarm LED (AL)</td><td>Flashes to indicate system alarms or errors.</td></tr><tr><td>7</td><td>Product model</td><td>Main unit product model </td></tr><tr><td>8</td><td>Locking clip for DIN rail mounting</td><td>Mounts onto a 35mm DIN rail.</td></tr><tr><td>9</td><td>Split-core CT locking clasp</td><td>Ensure the clasp is securely locked for precise measurement.</td></tr><tr><td>10</td><td>Positive power flow direction</td><td>Indicates positive power flow direction for CT(L1), CT(L1), and CT(L3) installation.</td></tr></tbody></table>

***

### 3. Technical Data

<table data-header-hidden><thead><tr><th width="342"></th><th></th></tr></thead><tbody><tr><td>Rated voltage (Input)</td><td>~220-240 VAC phase to neutral, 50/60 Hz<br>~380-415 VAC phase to phase, 50/60 Hz<sup>1)</sup></td></tr><tr><td>Max monitoring current <em>I</em><sub>max</sub></td><td>50A / 120A / 300A / 400A</td></tr><tr><td>Over-voltage category</td><td>III</td></tr><tr><td>Rated insolating voltage <em>U</em><sub>i</sub></td><td>440V</td></tr><tr><td>Rated impulse withstand voltage <em>U</em>imp</td><td>4kV</td></tr><tr><td>Pollution degree</td><td>3</td></tr><tr><td>Protection degree</td><td>IP20</td></tr><tr><td>Power Supply</td><td>100~240 VAC (L1-N)</td></tr><tr><td>Energy measurement accuracy</td><td>Class 1 (IEC 61557-12)</td></tr><tr><td>Maximum Power consumption</td><td>≤ 2VA</td></tr><tr><td>Rated operating temperature</td><td>-25℃ to 55℃</td></tr><tr><td>Main module dimension</td><td>113.7×18.0×65.9mm</td></tr><tr><td>Clamp CT apertures</td><td>Ø10 / Ø16 / Ø24 / Ø36 mm</td></tr><tr><td>Communication Type</td><td>Wireless<sup>2)</sup>: BLE+Wi-Fi; Zigbee<br>Wired: RS485</td></tr></tbody></table>

**Remark:**\
1\) Not suitable for 3P3W installation.

2\) Two variants of main module available with different connectivity - Tuya WiFI (SDM01G2-TWM-\*), and Standard Zigbee 3.0 (SDM01G2-SZM-\*)

***

### 4. Mechanical Outline

* **Dimension:** Unit in mm
* **Main Unit:** Monitoring module for DIN-rail installation (18mm width)

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FsVVBSHX2do6iPz82QDpP%2Fimage.png?alt=media&amp;token=b979d225-7bd5-4712-b600-495f8acf9b2e" alt=""><figcaption></figcaption></figure>

* **Split-core Current Transformer - 50A (CT Clamp - 50A):**

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FSaY4TGxxEPzIqrrQXGyV%2FBSCT-10C-Cable-B.png?alt=media&amp;token=ff34bbc2-637e-44b0-a0bd-b6968e808763" alt=""><figcaption></figcaption></figure>

* **Split-core Current Transformer - 120A (CT Clamp - 120A):**

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FL9hClaStxpxhxnl7xLx9%2FBSCT-16B-Cable-B.png?alt=media&amp;token=d2ba0ca0-4ab7-4c48-b4d2-fbbc2a15e89e" alt=""><figcaption></figcaption></figure>

* **Split-core Current Transformer - 300A (CT Clamp - 300A):**

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FJXN7UEBaXeDLOfTInKtI%2FBSCT-24X.png?alt=media&amp;token=46761db4-47ef-4855-b226-556114ec94cf" alt=""><figcaption></figcaption></figure>

* **Split-core Current Transformer - 400A (CT Clamp - 400A):**

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2F0uq7qDCQrQaokcflOCvU%2FBSCT-36X.png?alt=media&amp;token=54655811-5010-4cf1-9899-ac1a401be985" alt=""><figcaption></figcaption></figure>

***

### 5. Electrical Installation&#x20;

#### Wiring Diagram

**⚠️ Safety Remarks:**

* The device must be associated with easily accessible upstream protective devices ‒ such as miniature circuit breakers (MCB).
* The device must be installed, operated, serviced, and maintained **ONLY** by qualified professionals.
* Please read the user guide carefully before installation for detailed wiring diagrams and safety precautions.

<p align="center"><strong>Three-phase (3P4W) System Wiring</strong></p>

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2F9ovIEMDjP6LAr3MQnPa7%2FSDM01G2-3PN-Wiring.png?alt=media&amp;token=ac05a196-30e9-4966-a7e5-697aa4cc7260" alt=""><figcaption></figcaption></figure>

<p align="center"></p>

<p align="center"><strong>Single-phase System Wiring up to 3 Branch Circuits</strong></p>

<figure><img src="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FO5abtrL6mgkEOBL5cYqR%2FSDM01G2-3-1PN-Circuits-Wiring.png?alt=media&amp;token=b9723b26-e742-4517-9e61-8a0111d229ae" alt=""><figcaption></figcaption></figure>

**Note:**&#x20;

1. Voltage measurement must match current measurement – V<sub>1</sub> (I<sub>1</sub>) ; V<sub>2</sub> (I<sub>2</sub>) ; V<sub>3</sub> (I<sub>3</sub>) , to measure electrical data correctly.
2. It can cause product damage, if the blue cable for N connection is connected to phase conductors by mistake

#### Installation Video

*🚧Coming soon...*

***

### 6. User Interface

#### Reset Button

Press and hold for 3–5 seconds to enter pairing mode.

#### LED Indicator<br>

{% tabs %}
{% tab title="Tuya WiFi " %}

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td><strong>Solid ON</strong></td><td>Device connected - the device is online and functioning normally with cloud connectivity.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FkwU3dFE15wPbfD9F0pNa%2FGreen-Solid.jpg?alt=media&amp;token=25208946-1df1-4614-b704-4517fd007118">Green-Solid.jpg</a></td></tr><tr><td><strong>Flashing at 2Hz</strong></td><td>Pairing mode – press and hold the reset button until the LED flashes rapidly.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FWbizEiq4JMS3j9XhBsxE%2FGreen-Flashing-at-2Hz.jpg?alt=media&amp;token=bf22526a-6206-4d63-85c2-bba85ba1ae3b">Green-Flashing-at-2Hz.jpg</a></td></tr><tr><td><strong>Flashing at 0.5Hz</strong></td><td>Reconnecting to network - the device is attempting to reconnect using saved network settings.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FScRpvSt4h8Am2wmcoKxd%2FGreen-Flashing-at-0.5Hz.jpg?alt=media&amp;token=8c349252-fdd8-4395-85a7-db01b7558cdf">Green-Flashing-at-0.5Hz.jpg</a></td></tr><tr><td><strong>Flashing at 1Hz</strong></td><td>Network connected, cloud unreachable - the device is connected to Wi-Fi/Zigbee, but failed to reach the cloud.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FKX5vs26feuR7YXnc2kTE%2FGreen-Flashing-at-1Hz.jpg?alt=media&amp;token=2153be0f-7635-4f9e-a44e-7064b0dc2f12">Green-Flashing-at-1Hz.jpg</a></td></tr><tr><td><strong>Flashing at 0.25Hz</strong></td><td>The device failed internal self-check. Please power off, restart, and reconfigure the network settings.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FOZwF7G2PEbBtuaDzEYfW%2FGreen-Flashing-at-0.25Hz.jpg?alt=media&amp;token=82a8f1f8-d5e9-44b7-97df-7fd9cee4af83">Green-Flashing-at-0.25Hz.jpg</a></td></tr><tr><td><strong>Flashing at 1Hz</strong></td><td>Alarm reminder -<br>The device has detected a fault. Please check the wiring and power supply.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2Fgjz0xceslVOF4qKWMqa0%2FRed-Flashing-at-1Hz.jpg?alt=media&amp;token=202171d9-496d-4264-9b50-a7ab0d175d0c">Red-Flashing-at-1Hz.jpg</a></td></tr></tbody></table>
{% endtab %}

{% tab title="Standard Zigbee 3.0" %}

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td><strong>Solid ON</strong></td><td>Zigbee connected, BLE disconnected – the device is connected to a Zigbee network while BLE is turned off or not connected.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FkwU3dFE15wPbfD9F0pNa%2FGreen-Solid.jpg?alt=media&amp;token=25208946-1df1-4614-b704-4517fd007118">Green-Solid.jpg</a></td></tr><tr><td><strong>Flashing at 2Hz</strong></td><td>Pairing mode – press and hold the reset button until the LED flashes rapidly.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FWbizEiq4JMS3j9XhBsxE%2FGreen-Flashing-at-2Hz.jpg?alt=media&amp;token=bf22526a-6206-4d63-85c2-bba85ba1ae3b">Green-Flashing-at-2Hz.jpg</a></td></tr><tr><td><strong>Flashing at 0.5Hz</strong></td><td>Reconnecting to network - the device is attempting to reconnect both BLE (if available) and Zigbee using saved settings.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FScRpvSt4h8Am2wmcoKxd%2FGreen-Flashing-at-0.5Hz.jpg?alt=media&amp;token=8c349252-fdd8-4395-85a7-db01b7558cdf">Green-Flashing-at-0.5Hz.jpg</a></td></tr><tr><td><strong>Flashing at 1Hz</strong></td><td>BLE connected(if available)  - the LED flashes at 1Hz whenever BLE is connected, regardless of Zigbee status.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FKX5vs26feuR7YXnc2kTE%2FGreen-Flashing-at-1Hz.jpg?alt=media&amp;token=2153be0f-7635-4f9e-a44e-7064b0dc2f12">Green-Flashing-at-1Hz.jpg</a></td></tr><tr><td><strong>Flashing at 0.25Hz</strong></td><td>The device failed internal self-check. Please power off, restart, and reconfigure the network settings.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2FOZwF7G2PEbBtuaDzEYfW%2FGreen-Flashing-at-0.25Hz.jpg?alt=media&amp;token=82a8f1f8-d5e9-44b7-97df-7fd9cee4af83">Green-Flashing-at-0.25Hz.jpg</a></td></tr><tr><td><strong>Flashing at 1Hz</strong></td><td>The device has detected a fault. Please check the wiring and power supply.</td><td data-object-fit="contain"><a href="https://68488808-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTmsWivaZjkubbVKrCezC%2Fuploads%2Fgjz0xceslVOF4qKWMqa0%2FRed-Flashing-at-1Hz.jpg?alt=media&amp;token=202171d9-496d-4264-9b50-a7ab0d175d0c">Red-Flashing-at-1Hz.jpg</a></td></tr></tbody></table>
{% endtab %}
{% endtabs %}

***

### 7. System Integration

#### Wireless communication

Products equipped with different communication SoC firmwares connect to different systems and cloud platforms. Users can select the appropriate version based on their specific application requirements.

{% tabs %}
{% tab title="Tuya WiFi " %}
The Tuya WiFi version can only be integrated into the Tuya Cloud using Tuya's encrypted MQTT communication. It cannot be directly integrated with any third-party cloud platforms, ecosystems, or gateways. Third-party clouds or edge gateways need to be integrated via Tuya cloud APIs. For details, please refer to Tuya's developer documentation.

**Note:**&#x20;

1. Tuya's strategy for adjusting the cloud data reporting frequency is not fully disclosed. Based on the latest updates as of April 2026, provided the daily data reporting traffic limit is not exceeded, the fastest expected reporting interval will be between 5 to 15 minutes.
2. Tuya's Smart Life App is user-friendly and straightforward, making it ideal for entry-level smart home users who prefer simplicity and basic energy consumption monitoring.
   {% endtab %}

{% tab title="Standard Zigbee 3.0" %}
The Standard Zigbee 3.0 version can seamlessly connects to third-party gateways. Thanks to the standardized application-layer integration of Zigbee 3.0, it is highly convenient and widely applicable for both residential and commercial building projects.

Currently supported smart home ecosystems include:

* **Home Assistant:** Integration via Zigbee2MQTT [SDM01](https://www.zigbee2mqtt.io/devices/SDM01W-U01.html#bituo-technik-sdm01w-u01)
* **SmartThings:** Integration via the SmartThings Hub driver (officially approved).
* **Homey:** Integration via the [Bituo Technik App ](https://homey.app/en-us/app/com.bituotechnik.iot/BITUO-TECHNIK/)

**You can find information about the commonly used Zigbee Cluster Library on** [**this page**](https://bituo-technik.gitbook.io/hc/device-api/zigbee/spm-sdm-zigbee-profile)**.**
{% endtab %}
{% endtabs %}

#### Wired communication

SDM01 provides a Modbus RTU over RS485 interface, making it convenient to use as a wired Modbus RTU meter. You can view the Modbus RTU register address information by clicking the page below.

{% content-ref url="/pages/cIwsN5OFt26gvjZMt9c1" %}
[SDM01 Modbus RTU Map](/device-api/sdm01-modbus-rtu-map.md)
{% endcontent-ref %}

***

### 8. Ordering Information

{% tabs %}
{% tab title="Tuya Wi-Fi" %}

<table><thead><tr><th width="75.7777099609375">#</th><th width="175.555419921875">Ordering number</th><th>Description</th></tr></thead><tbody><tr><td>1</td><td>SDM01G2-TWM-12</td><td>SDM01 SCTA-3×120A/Φ16 Wi-Fi (Tuya LAN+)+RS485</td></tr><tr><td>2</td><td>SDM01G2-TWM-20</td><td>SDM01 SCTA-3×200A/Φ20 Wi-Fi (Tuya LAN+)+RS485</td></tr><tr><td>3</td><td>SDM01G2-TWM-30</td><td>SDM01 SCTA-3×300A/Φ16 Wi-Fi (Tuya LAN+)+RS485</td></tr><tr><td>4</td><td>SDM01G2-TWM-40</td><td>SDM01 SCTA-3×400A/Φ20 Wi-Fi (Tuya LAN+)+RS485</td></tr></tbody></table>

1\) Tuya LAN+: Tuya LAN+ is a specific Wi-Fi SoC firmware provided by Tuya Smart that features local area network (LAN) communication. It is suitable for local LAN communication with products such as EV chargers, microinverters, and micro-energy storage systems that are also equipped with Tuya LAN+ communication firmware. This model can only be purchased through Tuya's official or designated channels.
{% endtab %}

{% tab title="Standard Zigbee 3.0" %}

<table><thead><tr><th width="67.8887939453125">#</th><th width="186.6666259765625">Ordering number</th><th>Description</th></tr></thead><tbody><tr><td>1</td><td>SDM01-TZM-12-U01</td><td>SDM01 SCTA-3×120A/Φ16 Zigbee (Std. ZB3.0)+RS485</td></tr><tr><td>2</td><td>SDM01-TZM-20-U01</td><td>SDM01 SCTA-3×200A/Φ20 Zigbee (Std. ZB3.0)+RS485</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

***

### 9. FAQ&#x20;

{% content-ref url="/pages/149DFxm5iomFCS9alhv5" %}
[FAQ](/faq/overview.md)
{% endcontent-ref %}

***

### 10. Troubleshooting

{% content-ref url="/pages/td5Nnli4rm9AAhvTaYLk" %}
[Troubleshooting](/troubleshooting/overview.md)
{% endcontent-ref %}

***

### 11. Printed User Guide

{% file src="/files/R2XSkM36v8wFWtnYNgol" %}

### 12. Explore More