Frequently asked questions

Your electricity meter has a so-called customer interface. Through it the meter hands out your consumption data — encrypted, and in a format no off-the-shelf device can do anything with.

The Smart Meter Adapter plugs into that interface, decrypts the data on the device and serves it on your WiFi: as a dashboard in the browser, as a JSON API, over MQTT and via Modbus TCP.

By default the four central figures as OBIS values:

• 1-0:1.8.0 — active energy import, meter reading
• 1-0:2.8.0 — active energy export, meter reading
• 1-0:1.7.0 — instantaneous active power, import
• 1-0:2.7.0 — instantaneous active power, export

Over Modbus TCP further values are available depending on the meter, such as the current on each individual phase.

Important: which values actually arrive depends on the meter type and the grid operator. Only the data the meter actually emits is populated.

No. The adapter never opens a connection to the internet on its own. It works exclusively inside your local network, and decryption happens on the device itself.

If you want to send the data to an external service you have to set that up deliberately — for example by pointing the MQTT client at a broker on the internet.

No. No consumption values are stored on the device. The adapter passes readings through — whatever you do not fetch or record yourself is gone.

For a history you need a system that receives and stores the values, for instance a database behind your MQTT broker.

A maximum of three concurrent connections. If further clients want access, a new login is required.

If you need the data in many places, MQTT is the better route: the adapter pushes readings to your broker, and any number of clients subscribe to the broker rather than to the adapter.

Typically 1 watt, depending on WiFi signal strength. Running continuously that is roughly 9 kWh a year.

That depends solely on your meter, not on your preferences:

• MBUS variant — for meters with an M-Bus interface and for meters that transmit over Wireless M-Bus.
• UART variant — for meters with a serial customer interface, called DSMR, P1 or HAN depending on the manufacturer.
• UART variant + IR reading head — for meters that only output their data optically. The head conforms to IEC 62056-21.

The meter finder makes the decision for you: pick your grid operator and meter model, done.

Only from the rating label. The two variants look identical from the outside — the difference is the interface board inside.

You do not have to choose: both cables are included with every adapter. Most meters use RJ12, a few — the Kamstrup devices among them — use RJ45.

If you want to use a third-party cable, two restrictions apply: it must have a mirrored pinout, and it must be no longer than 3 metres.

Yes. The IR reading head conforms to IEC 62056-21, the international standard for the optical interface on electricity meters. It defines the dimensions, the position of the magnetic mount and the optical transmission.

The head therefore fits the standardised optical interface of practically every smart meter, whichever manufacturer built it. It is Ø 32 mm, 24 mm deep, and attaches magnetically to the meter.

Whether your meter is actually read over the optical interface, or over M-Bus or DSMR instead, is answered by the meter finder.

Send us the grid operator and the type designation — both are on the label on the front of the meter. We will check whether the device already works or can be added.

New meters are added continuously and support arrives by firmware update. For companies that need support for a specific meter, we offer integration of a new smart meter as a fixed-price service.

The adapter, RJ12 and RJ45 connection cables, a USB-C cable for power, the detachable WiFi antenna, a DIN rail clip and a double-sided adhesive pad.

The IR reading head is ordered separately and comes with a magnetic mount and its own RJ12 cable.

Usually not. The adapter plugs into the freely accessible customer interface; no work on your electrical installation is involved.

If your meter’s customer interface sits behind a sealed terminal cover, contact your grid operator — only their staff may break the seal.

In three ways: on a standard DIN rail with the supplied clip, on a wall, or with the double-sided adhesive pad. The adapter is only one module unit wide and therefore fits into practically any distribution board.

Keep the adapter indoors — the protection class is IP20.

It depends on the interface:

• Infrared: USB is mandatory. The reading head has no supply of its own.
• Wireless M-Bus: USB is recommended.
• M-Bus: some meters power the adapter through the interface, but this is not guaranteed. If you see dropouts or restarts, connect USB.
• DSMR: many meters carry power on the interface. Where they do not, you need USB.

USB is always required during a firmware update.

The reading head attaches magnetically to the meter’s optical interface — the mount conforms to IEC 62056-21 and therefore fits practically every smart meter. Two things matter:

• The cable must exit downwards.
• The head must sit straight on the meter, not at an angle.

Careful: the magnet is strong. Attach the head gently to avoid pinching your fingers.

The mounting position affects reception noticeably. Place the adapter as close to the meter as possible and power it over USB.

Walls and especially metal distribution cabinets attenuate the radio signal considerably. If the adapter sits inside a closed metal cabinet, that is usually the cause.

After plugging it in the status LED is steady blue — the device is ready for a direct connection.

1. Connect your phone, tablet or laptop to the adapter’s WiFi. It is called energie followed by the serial number; the exact name is printed on the side label.
2. The password is energie1.
3. The setup page opens automatically. If it does not, go to http://192.168.100.1.
4. The wizard walks you through the administrator password, meter selection, meter key and WiFi settings.

Open it manually: http://192.168.100.1.

If even joining the adapter’s WiFi fails, it often helps to turn off mobile data on your device. Otherwise phones fall back to the mobile network as soon as they notice the WiFi has no internet access.

Once the wizard finishes, the adapter joins your WiFi and tries to redirect you to its new address automatically. For that you have to disconnect your device from the energie WiFi and join your own network.

If the redirect does not happen, reach the device at http://sma.local — this works on Apple devices and sometimes on Windows — or directly via its IP address.

Tip: note the IP address during setup. Alternatively assign the adapter a fixed address in your router.

Press the button on the device briefly, up to 3 seconds. The access point is reactivated, the LED turns blue, and you can connect directly just as during initial setup.

No. You set the administrator password during initial setup — there is no factory password.

If you have forgotten it, the only route is a factory reset: hold the button for at least 10 seconds. This erases all settings and meter data, so you will have to enter the meter key again too.

Yes. During setup and later under Security you choose whether access is allowed over HTTPS only, or over HTTP as well.

From your grid operator. The key — depending on the operator also called customer key, data key or simply key — is unique to each meter and is issued free of charge.

Usually you request it through your grid operator’s customer portal or from their customer service. Have your metering point number and meter number to hand.

Without this key the adapter cannot decrypt the meter’s data.

The meter key you entered does not match the meter. Go back one step with Zurück and enter it again.

Where possible do not retype the key — copy and paste it. Confusing 0 with O, or 1 with l, is by far the most common cause.

Also check that the key really belongs to this meter — with several metering points the keys are easily mixed up.

That is normal. Typically the check completes in about 5 seconds, but depending on the meter type it can take up to 5 minutes — the adapter is waiting for the meter’s next data telegram.

Yes. The meter selection includes a simulator mode. No meter key is required, and you can exercise the dashboard and the interfaces against generated values — useful for building an integration before the meter is reachable.

Red means one of two faults: the adapter is receiving no data from the meter, or the WiFi connection is failing.

Check in order: is the cable seated firmly in the right socket? Is the configured meter type correct? Is the WiFi password still valid, and does the signal reach the distribution board?

If the adapter is reachable over WiFi, the counters meter_valid_package_cnt and meter_invalid_package_cnt under /api/sma/status.json show whether any telegrams are arriving at all.

The device is in recovery mode. This typically happens when a firmware update was interrupted.

Connect the device over USB and leave it connected. If you cannot get any further, get in touch.

On Wireless M-Bus that is intended: the LED does not blink on data reception but stays steady green. On every other interface a short blink acknowledges each received packet.

Two ways:

• Hold the button on the device for at least 10 seconds. The LED shows red for 2 seconds, then the reset is done.
• In the web interface under System, restore factory settings.

Either way all settings and meter data are erased.

Two endpoints are available:

• https://<IP>/api/data/measurement.json — current readings
• https://<IP>/api/sma/status.json — device status and diagnostics

An authorization token must be sent in the header. Generate and copy the token in the web interface under API → JSON, where an example request is also shown.

The response is keyed by OBIS code, each value with a timestamp. Details and a complete example are in the interface documentation.

The adapter is an MQTT client: you point it at your own broker and it publishes the meter data as JSON to a topic you choose.

The settings are in the web interface under API → MQTT. There you enable the interface and enter broker, topic and credentials.

The adapter does not include a broker. If you do not run one yet, Mosquitto on any machine in your home network is the usual starting point.

You have to add an offset of 69. Registers 0 to 69 are reserved for a header, so “position 1” from the SunSpec specification lives at register 70.

Examples:

• Registers 73–75: current on phases L1, L2, L3
• Register 76: current scale factor (default −3, i.e. 10⁻³)
• Registers 109–110: active energy export
• Registers 116–117: active energy import

Register values are scaled, and the scale factor lives in a separate register. Each section has a scale factor associated with it, for example “AC Voltage Scale Factor”.

For current the default is −3, so the raw values are in milliamperes. Read the factor rather than assuming it — it can differ by meter.

Only the data the meter actually provides is populated. Which values those are depends on the meter type and the grid operator — many meters do not report per-phase values, for instance.

In the dashboard, missing points simply leave a gap in the chart; that is not a fault of the adapter.

Readings are drawn as points and interpolated in between. When no current value is available because of a connection problem, no point is drawn.

If the gaps accumulate, check WiFi signal strength and power supply — on M-Bus, marginal power from the meter is a typical cause.

Yes — through the open interfaces, not through a dedicated integration. There are three routes:

• MQTT is the most convenient: point the adapter at your broker, then define MQTT sensors in Home Assistant on that topic.
• REST via /api/data/measurement.json with the authorization token.
• Modbus TCP, if you are integrating Modbus devices anyway.

Note: we do not ship a ready-made Home Assistant integration and have not tested the examples in every configuration. Feedback is welcome.

All of these speak MQTT, HTTP or Modbus TCP, so the adapter can be connected to them. We do not ship an integration tailored to any one of them.

For companies that want a specific platform connected properly, we offer integration into your MQTT system as a fixed-price service — including topic structure, payload format and auto-discovery to your specification.

That is a typical use case: the adapter reports import and export within seconds, which is usually enough for surplus control.

For inverters and building controls, Modbus TCP is often the most direct route, because many devices read SunSpec registers natively.

Note that the update rate is dictated by the meter, not by the adapter. How quickly new values arrive differs by meter type and grid operator.

The same device, without being tied to our firmware: the adapter carries an ESP32-S2 that you program yourself. Enclosure, power supply, antenna, meter interface, CE marking and DIN-rail mounting are done — all that is left is your firmware.

The extension connector pinout and the interface-board detection are published on the Open-CPU page.

No. No NDA, no licence fee, no registration, and no surcharge over the Secured variant. You buy hardware and do what you like with it.

Yes. We flash your firmware image at the factory, inject per-device data such as serial numbers or certificates, and test every unit following your procedure.

The price is €200 one-off plus €5 per device, net. You can add the service directly in the business form.

Through the DETECT signal. Each extension board carries its own pulldown resistor, and the measured ADC value identifies it unambiguously:

• 2258 (0.30 V, 10 kΩ) — MBUS
• 3526 (0.43 V, 15 kΩ) — WMBUS
• 6718 (0.82 V, 33 kΩ) — P1 / IR

Two ways, depending on the state of the device:

• Not yet configured: directly in the setup wizard. This is the usual route for adding support for further meters.
• Already configured: in the web interface under System.

A USB power supply is mandatory during the update. Do not disconnect the device from power while it runs — doing so can destroy it.

Not on the Secured variant: it accepts only validly signed firmware images.

If you want to run your own software on the device, the Open-CPU variant is the way to do it. It costs the same and requires no NDA.

The selection is limited by default to the meters your adapter variant can serve. If your meter is not there, first check that you have the right variant — the rating label says which.

If the variant is right, a firmware update usually helps: new meters arrive through updates, and the setup wizard lets you update the firmware before configuring anything.

Single units go through Amazon — with Amazon shipping and Amazon returns. The links are under Buy.

While the Amazon listings are not live yet, we are happy to take your order directly by email.

From 25 units in total, counted across all items together. Put your quantities together in the business form and request a quote — you see the net total immediately.

For larger volumes or recurring call-offs, talk to us directly.

For Amazon orders, the delivery times shown there apply. For business customers the lead time depends on quantity and any customisation — the exact commitment is stated in our quote.