My electricity provider (ČEZ Distribuce) has just installed a new smart meter at my home. Up until this time I was using the Home Assistant Glow to track my household energy consumption. So I was excited to finnaly get my hands on the new smart meter and see if I can read out the data from it. Unfortunately it was not as easy as I hoped, but after many failed attempts I managed to get it working, and I want to share my experience with you.
Distribution company website (in czech) | Datasheet
The Sagecom XT211 is a three-phase smart meter that supports DLMS/COSEM protocol for data communication. It has a built-in RS485 interface that can be used to read out the meter data. The meter is configured for PUSH communication, which means it sends data every 60 seconds without the need for polling.
In my case, the meters port was connected to the WM-RelayBox device, which is used for remote disconnection of the electricity supply. The RS485 interface is accessible via an RJ12 port that is located on the device.
Datasheet | Installation Guide | Quick Guide
The RelayBox connects to the electricity meter (via its RJ12 E-Meter interface) and it receives unidirectional (one-way) DLMS / COSEM „push” commands and messages from the Head-end System through the meter.
Then it executes the relay switch requests and sends all data provided by the smart meter to the Customer Interface HAN / P1 output interface (separate, isolated RJ12 port) of the RelayBox.
The HAN port is an isolated RJ12 port that provides access to the data sent by the electricity meter. The port uses RS485 communication with the following pinout:
Some sources say that the 6th pin is connected to GND, while others say it is not used. I only have pins 3 and 4 connected, because I only need the data lines for RS485 communication (and I only had an RJ11 telephone cable that does not have pins 1 and 6).
| Pin | Signal |
|---|---|
| 1 | Not used |
| 2 | Not used |
| 3 | Data A (+) |
| 4 | Data B (-) |
| 5 | Not used |
| 6 | GND |
To connect the HAN port to my ESPHome device, I used a RS485 to TTL converter. I used this AliExpress TTL To RS485 module, but there are many other similar modules available.
The RS485 communication parameters are defined in připojovací podmínky NN document provided by ČEZ Distribuce:
| Parameter | Value |
|---|---|
| Baud rate | 9600 bps |
| Data bits | 8 |
| Start bits | 0 |
| Stop bits | 1 |
| Parity | None |
| Flow control | None |
One thing I liked about the Home Assistant Glow meter was that it updated fairly quickly (depending on the pulse frequency). The new meter sends PUSH messages only every 60 seconds, which is not ideal for real-time monitoring.
So I decided to get the best of both worlds and use the PulseMeter in Home Assistant for real-time power consumption (W) monitoring, while using the ESPHome DLMS/Cosem readout for the energy (kWh) monitoring.
For more information about the PulseMeter, see the Home Assistant Glow documentation.
I mounted the ESPHome device and the RS485 to TTL converter inside a small project box.
I took the photodiode sensor box from the Home Assistant Glow meter.
I made a Frame for mounting the sensor box on the XT211 meter.
LM393 Photo-diode sensor:
- VCC to 5V
- GND to GND
- DO (Digital Output) to GPIO6
- AO (Analog Output) to GPIO5 (analog input, optional)
RS485 to TTL converter:
- VCC to 5V
- GND to GND
- TXD to RX (GPIO21)
- RXD to TX (GPIO22)
HAN port (RJ12 / RJ11):
- B- (Data B) to HAN port pin 4
- A+ (Data A) to HAN port pin 3
- GND to pin 6 (optional)
Activity LED (optional):
- Anode (longer leg) to GPIO4 (with 220 ohm resistor in series)
- Cathode (shorter leg) to GND
Power Led (optional):
- Anode (longer leg) to 5V (with 4700 ohm resistor in series - lower brightness)
- Cathode (shorter leg) to GND
To read out the DLMS/Cosem PUSH messages from the Sagecom XT211 meter, I modified the existing esphome-dlms-cosem.
Removed the polling functionality, fixed some bugs, and added support for binary sensors.
For a more detailed description of the component, see the esphome-dlms-cosem repository from latonita
For full configuration file, see: esphome-smartmeter.yaml
In your esphome configuration file, add the following lines at the top (for esp32c3):
esp32:
variant: esp32c3
framework:
type: esp-idfAdd the external component to your ESPHome configuration:
external_components:
- source: github://Tomer27cz/xt211
components: [xt211]
refresh: 1sThen configure the DLMS/Cosem component:
- push_show_log: true (optional, for debugging purposes - shows all received PUSH messages in the log)
Disable the log onece everything is working fine.
uart:
id: bus_1
tx_pin: GPIO20
rx_pin: GPIO21
baud_rate: 9600
data_bits: 8
parity: NONE
stop_bits: 1
xt211:
push_show_log: trueMy electricity consumption is measured in kWh, but the meter sends the value in Wh. Therefore, I use a lambda filter to convert the value from Wh to kWh by dividing it by 1000.
sensor:
- platform: xt211
id: active_energy_consumed
name: "Energy"
obis_code: 1.0.1.8.0.255
unit_of_measurement: kWh
accuracy_decimals: 3
device_class: energy
state_class: total_increasing
filters:
- lambda: "return x/1000.0;"The binary sensor is false when the value is 0, and true when the value is anything else.
binary_sensor:
- platform: xt211
name: "Relay 1"
obis_code: 0.1.96.3.10.255The text sensor is used to display string values sent by the meter.
text_sensor:
- platform: xt211
name: "Serial number"
obis_code: 0.0.96.1.1.255
entity_category: diagnostictime:
- platform: homeassistant
id: homeassistant_time
number:
- platform: template
id: select_pulse_rate
name: 'Puls rate - imp/kWh'
optimistic: true
mode: box
min_value: 100
max_value: 10000
step: 100
restore_value: yes
initial_value: 1000
sensor:
- platform: pulse_meter
name: 'Pulse Power Consumption'
id: sensor_energy_pulse_meter
unit_of_measurement: 'W'
state_class: measurement
device_class: power
icon: mdi:flash-outline
accuracy_decimals: 0
pin: GPIO6
on_raw_value:
then:
- switch.turn_on: indicator_led
- delay: 100ms
- switch.turn_off: indicator_led
on_value:
then:
- sensor.template.publish:
id: power_consumption
state: !lambda 'return x;'
# dont know what this does but it was commented out
internal_filter: 100ms
filters:
# Sensor can quickly transition between on and off (unintendet bevaior)
# this meter has max load of 13.27 kW (32A - 3 Phase - 240V) = pulse every 270ms at full load
- debounce: 100ms
# multiply value = (60 / imp value) * 1000
# - multiply: 60
# Clamp to physically possible max (13.3 kW) - if larger then drop the value
- lambda: |-
float watts = x * ((60.0 / id(select_pulse_rate).state) * 1000.0);
if (watts > 13300.0) return NAN;
return watts;
# Update the sensor with an average every 10th second. See
# https://github.com/klaasnicolaas/home-assistant-glow/#reduce-the-amount-of-data-the-sensors-produce
# for more information.
#- throttle_average: 10s
# filter out impossible numbers
- filter_out: NaNWe create a template sensor that combines the power consumption from the PulseMeter and DLMS/Cosem sensors. Every time any of the sensors update, they also update the combined sensor.
sensor:
- platform: template
id: power_consumption
name: "Power Consumption"
unit_of_measurement: 'W'
accuracy_decimals: 0
device_class: power
state_class: measurement
icon: mdi:flash
[... pulse meter from above ...]
- platform: xt211
id: active_power
name: "Active power consumption"
obis_code: 1.0.1.7.0.255
unit_of_measurement: W
accuracy_decimals: 0
device_class: power
state_class: measurement
on_value:
then:
- sensor.template.publish:
id: power_consumption
state: !lambda 'return x;'You can find the full list of OBIS codes in the vp_1-13.pdf document provided by ČEZ Distribuce.
| OBIS Code | Value | Description |
|---|---|---|
| 0-0:96.1.1.255 | SN meter | Výrobní číslo elektroměru (Device ID) |
| 0-0:96.3.10.255 | stav odpojovače | Indikace stavu odpojovače |
| 0-0:17.0.0.255 | limiter | Hodnota pro limiter |
| 0-1:96.3.10.255 | stav relé R1 | Stav relé R1 |
| 0-2:96.3.10.255 | stav relé R2 | Stav relé R2 |
| 0-3:96.3.10.255 | stav relé R3 | Stav relé R3 |
| 0-4:96.3.10.255 | stav relé R4 | Stav relé R4 |
| 0-0:96.14.0.255 | aktuální tarif | Aktuální tarif |
| 1-0:1.7.0.255 | P+ | Okamžitý činný výkon odběru |
| 1-0:21.7.0.255 | P+ L1 | Okamžitý činný výkon v L1 |
| 1-0:41.7.0.255 | P+ L2 | Okamžitý činný výkon v L2 |
| 1-0:61.7.0.255 | P+ L3 | Okamžitý činný výkon v L3 |
| 1-0:2.7.0.255 | P- | Okamžitý činný výkon dodávky |
| 1-0:22.7.0.255 | P- L1 | Okamžitý činný výkon v L1 |
| 1-0:42.7.0.255 | P- L2 | Okamžitý činný výkon v L2 |
| 1-0:62.7.0.255 | P- L3 | Okamžitý činný výkon v L3 |
| 1-0:1.8.0.255 | A+ | Činná energie (+A) |
| 1-0:1.8.1.255 | A+ T1 | Činná energie tarif 1 (+A) |
| 1-0:1.8.2.255 | A+ T2 | Činná energie tarif 2 (+A) |
| 1-0:1.8.3.255 | A+ T3 | Činná energie tarif 3 (+A) |
| 1-0:1.8.4.255 | A+ T4 | Činná energie tarif 4 (+A) |
| 1-0:2.8.0.255 | A- | Činná energie (-A) |
The final esphome configuration file can be found here: esphome-smartmeter.yaml
The final setup includes:
- ESPHome device with DLMS/Cosem component
- RS485 to TTL converter
- LM393 Photo-diode sensor for PulseMeter
- Mounted inside a project box
- Connected to the HAN port of the WM-RelayBox
- Connected to Home Assistant via ESPHome integration
- Activity LED to indicate pulse detection
- Power LED to indicate power status
- Powered via 5V power supply (from USB power adapter)
- latonita - for the original esphome-dlms-cosem component