Tasmota cmnd=state Missing ENERGY Data on HLW8012, CSE7766, ADE7953, BL0937, PZEM Devices

User question

[WebApp Cmd 'Status 8' Result] Unknown command

Artificial Intelligence Response

Direct answer to the question

• “[WebApp Cmd 'Status 8' Result] Unknown command” means the firmware that is currently running on your Tasmota-based device was compiled without the energy-monitoring module (USE_ENERGY_SENSOR) or the command was malformed when it reached the device.
• In practice this happens almost exclusively when you flash one of the minimal / lite / display / IR / custom stripped builds or when the WebApp inserts an illegal “ =` ” sign instead of the single space required by Tasmota’s command grammar.
• Flash a build that contains the energy drivers (e.g. tasmota-sensors.bin) and send the command with the exact syntax

Status 8

over the console, MQTT (cmnd/<topic>/Status payload 8) or HTTP (/cm?cmnd=Status%208).

Key points

1. “Unknown command” = command never found → missing at compile time or corrupted in transmission.
2. Energy hardware absent or mis-configured would not raise “Unknown command”; you would receive an empty/zero ENERGY block instead.
3. Upgrade to a full “sensors” build, apply the correct module/template, then retry.

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Detailed problem analysis

1. Tasmota command registration
   • At boot each feature module registers its commands.
   • Status is always present, but the sub-handler for index 8 is compiled only if USE_ENERGY_SENSOR is enabled.
   • If absent, the dispatcher returns “Unknown command” the moment you ask for index 8.

2. Common situations that remove the handler
   a. Pre-compiled binaries with reduced footprint
   – tasmota-lite, tasmota-minimal, tasmota-ir, tasmota-display, many vendor-specific OTA binaries.
   b. DIY custom builds where #undef USE_ENERGY_SENSOR (or #define USE_NO_ENERGY_SENSOR) was set to save flash.
   c. Builds older than ca. v6.6 where energy code was still optional in the core binary.

3. Less frequent, but possible
   • Transport / syntax error (WebApp silently sends Status=8, %20 missing, extra CR LF, etc.).
   • A proxy-script that strips the space (causes Status8 which is not a legal command).
   • Very exotic edge cases: corrupted flash, run-time memory overwrite, but those will usually spam the log with exceptions before the console is ready.

4. Symptoms that are not “Unknown command”
   • “Energy shows all zeros” → sensors compiled but no chip found or GPIOs wrong.
   • “STATE command shows no ENERGY block” but 8 works → TelePeriod / retain logic, not compile time.

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Current information and trends (2024)

• Since v13 the official release set on OTA contains:
– tasmota.bin (standard, still includes energy in 2024 but could be dropped in future to fit ESP8285 1 MB)
– tasmota-sensors.bin (guaranteed energy drivers)
– tasmota-lite.bin (no energy)
• For ESP32-C3/S3 larger flash sizes allow “universal” builds, but for ESP8266 size pressure keeps energy optional.
• Community trend: use templates from the Blakadder repository to auto-assign GPIOs instead of choosing a fixed “module”.
• Future direction: CMake-based “boards.txt” style-selective build so a single binary can enable drivers at run-time on devices with ≥4 MB flash (experimental in 14.x nightlies).

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Supporting explanations and details

Command grammar (official docs):

<COMMAND><index><space><optional data>

No equals sign, no extra spaces. Therefore:
HTTP → /cm?cmnd=Status%208
MQTT → topic cmnd/myPlug/Status payload 8

Firmware variants and compiled-in features (excerpt):	Binary (ESP8266)	Flash size	Energy sensor code	Typical use case
tasmota-lite	≤ 448 kB	No	OTA staging, IR only, 1 MB chips
tasmota-minimal	≤ 350 kB	No	Mandatory first hop for very old devices
tasmota	≈ 640 kB	Yes* (as of 14.0)	General purpose
tasmota-sensors	≈ 780 kB	Yes	All sensor & energy drivers

*May be trimmed in future releases—always check the release notes.

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Ethical and legal aspects

• Firmware replacement voids many consumer warranties; ensure compliance with local regulations if the device is used for billing-grade metering.
• Safety: When reflashing mains-powered plugs, work through an isolation barrier and respect the creepage distances.

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Practical guidelines

1. Identify the running binary

   Status 2

   Check the parentheses after the version, e.g. 13.5.0(tasmota-lite)

2. Pick the correct upgrade path
   • If on minimal, first OTA-flash tasmota-sensors directly (since v12+ allows skipping the two-step).
   • If very old (<8.x), flash minimal → reboot → sensors.

3. Apply device template
   – Configuration ▸ Configure Other ▸ Template ▸ paste JSON ▸ Activate ▸ Save.

4. Reboot, open Console, and try

   Status 8

   You should now receive:

   {"StatusSNS":{"Time":"2024-06-01T12:34:56","ENERGY":{ ... }}}

5. Optional verification

   TelePeriod 10 // shorten for testing

   Watch tele/<dev>/SENSOR messages over MQTT to confirm continuous energy telemetry.

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Possible disclaimers or additional notes

• On 1 MB ESP8266 modules (Sonoff Basic R1, some older Gosund plugs) you might simply not have enough flash for a sensors build; compile a custom binary with only your IC driver and MQTT.
• Some proprietary energy ICs (e.g., BL09XX variants) demand correct board-level gain resistor values; mis-soldered boards will give nonsensical readings although the command works.

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Suggestions for further research

• Investigate Berry scripting in Tasmota 14.x to post-process energy data locally.
• Explore ESPHome as an alternative if you routinely need custom drivers and already use Home-Assistant.
• Look into the upcoming Matter/Thread branch of Tasmota if you plan to integrate energy monitoring with new smart-home hubs.

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Brief summary

“Unknown command” for Status 8 is almost always a compile-time omission: you are running a firmware build that lacks the energy-monitoring module or the WebApp mangled the command syntax.
Flash tasmota-sensors (or another full build), keep the exact Status 8 syntax, configure the correct template, and the command will return the ENERGY JSON block.

User question

how to get power [W] via http

Artificial Intelligence Response

Direct answer to the question

• Send an HTTP GET request to your Tasmota-based power-monitoring device:
  http://<device-ip>/cm?cmnd=Status%2010 (or the lighter Status%208).
• The reply is JSON. Read StatusSNS → ENERGY → Power.
• Works only if the hardware contains a metering IC (e.g. HLW8012, BL09XX) and the firmware you flashed has energy code enabled ( tasmota-sensors.bin or a custom build with USE_ENERGY_SENSOR).

Key points
• /cm?cmnd=Status 8/10 are the official REST endpoints for sensor/energy data.
• Space must be URL-encoded as %20.
• If the response lacks an ENERGY block or you get “Unknown command”, the firmware or template is wrong.
• Add user= and password= parameters when Web-UI authentication is enabled.

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Detailed problem analysis

1. Tasmota’s internal command tree
   • State → core status (relay, uptime, Wi-Fi) – never carries energy.
   • Status 8 → “SENSOR”: all sensor data, minimum overhead (≈ 0.6 kB).
   • Status 10 → “STATUS + SENSOR”: full module, network, and sensor report (≈ 1.2 kB).

2. JSON structure (excerpt)

   {
   "StatusSNS": {
   "Time": "2024-06-18T10:11:12",
   "ENERGY": {
   "TotalStartTime": "2024-06-01T00:00:00",
   "Total": 12.345,
   "Yesterday": 0.987,
   "Today": 0.123,
   "Power": 63, // <- instantaneous power in W
   "Voltage": 229,
   "Current": 0.275,
   "ApparentPower": 71,
   "ReactivePower": 27,
   "Factor": 0.89
   }
   }
   }

3. Firmware variants

   tasmota-minimal → no sensors, upgrade helper only
   tasmota-lite → small footprint, no energy
   tasmota → generic, may lose energy in future builds
   tasmota-sensors (*) → full sensor & energy support ← recommended

4. Why an “ENERGY” block may be missing
   • Wrong binary flashed.
   • Template/GPIO table does not map the metering IC pins.
   • Metering IC unpowered, faulty, or not present.

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Current information and trends

• Since Tasmota v13.x the preferred query for automation systems is Status 8; older tutorials still cite Status 10. Both remain valid in 2024.
• A new TelePeriod default of 300 s keeps the device from flooding the network; HTTP polling every 30–60 s is common.
• JSONPath extraction is supported directly in Home-Assistant 2024.6+, eliminating custom templates.

Future directions
• Core team is evaluating an “edge-metrics” endpoint returning only key values (power, voltage, current) to cut traffic for low-power IoT radios.
• ESP32-C6 ports add native HTTPS and Matter for secured energy data.

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Supporting explanations and details

Practical examples

• Browser test
http://192.168.1.123/cm?cmnd=Status%208

• curl + jq one-liner

curl -s "http://192.168.1.123/cm?cmnd=Status%208" | \
jq '.StatusSNS.ENERGY.Power'

• Python snippet

import requests
power = requests.get("http://192.168.1.123/cm?cmnd=Status%208",
timeout=5).json()["StatusSNS"]["ENERGY"]["Power"]
print(f"Power = {power} W")

Advanced (push instead of pull)

Rule1 ON ENERGY#Power DO WebSend [my.server.net] /hook?pw=%value% ENDON
Rule1 1

The device now POSTs the wattage whenever it changes, saving bandwidth.

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Ethical and legal aspects

• Network exposure: opening port-80 to the Internet can leak live consumption profiles. Use VPN or MQTT-over-TLS for remote access.
• Electrical safety: never exceed the plug’s rated current; inaccurate readings or overheating can cause fire.
• GDPR / CCPA: power data is personal usage information—treat logs accordingly.

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Practical guidelines

Implementation checklist

1. Flash tasmota-sensors.bin (Web UI → Firmware upgrade, or OTA URL).
2. Apply the correct template (Configuration → Configure Other).
3. Reboot, open console, ensure you see a line such as:
   HLW8012: Voltage=229.5V Current=0.27A Power=63W.
4. Test with Status 8 URL.
5. Integrate into your automation:
   • Node-RED: HTTP-request → JSON node → msg.payload.StatusSNS.ENERGY.Power.
   • Home-Assistant: RESTful Sensor platform.

Common pitfalls & fixes
• “401 Unauthorized” → supply credentials (http://user:pass@ip/...).
• Power always 0 W → load below metering IC’s threshold; calibrate with EnergyCal.
• JSON decode error → configure Content-Type: application/json if using custom HTTP libraries.

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Possible disclaimers or additional notes

• Single-value query (cm?cmnd=Power) returns relay state, not wattage—often confused in older blog posts.
• Meter accuracy is typically ±1 % after calibration; cheap plugs may drift.
• HTTP traffic is plain-text; consider MQTT-TLS or HTTPS proxy in security-sensitive environments.

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Suggestions for further research

• Explore Tasmota’s Script engine to build custom REST endpoints.
• Investigate ESPHome if YAML-based configuration is preferred.
• Look at IEC 62053-21 class-2 or class-1 certified meters for billing-grade accuracy.
• Study upcoming Matter-Energy spec for unified smart-home power metering.

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Brief summary

Query Status%208 or Status%2010 on the /cm endpoint of a Tasmota plug that has energy-capable firmware, parse ENERGY.Power, and you have the instantaneous power in watts. Ensure the correct firmware/template, URL-encode the space, authenticate if needed, and secure the traffic if it leaves your LAN.