WAGO 879-3020
Reads energy metering data from Wago 3-phase electricity meters via Modbus RTU.
Template for WAGO 879-3020 and compatible 3-phase electricity meters via Modbus RTU. It reads per-phase voltage, current, and power, as well as total active, reactive, and apparent power, frequency, and energy import/export counters. No writable registers are included.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 18, read only
- Brand
- Wago
- Key readings
- Voltage L1 to L3 · Current L1 to L3 · Power L1 to L3 · Frequency · Total active/apparent/reactive power · Total energy import/export
- Compatible models
- 879-3000 4PU · 879-3020 4PS · 879-3040 2PU CT
- Last updated
Registers (18)
18 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Voltage L1 | V | Read | |||
| Voltage L2 | V | Read | |||
| Voltage L3 | V | Read | |||
| Current L1 | A | Read | |||
| Current L2 | A | Read | |||
| Current L3 | A | Read | |||
| Power L1 | kW | Read | |||
| Power L2 | kW | Read | |||
| Power L3 | kW | Read | |||
| Frequency | Hz | Read | |||
| Total active power | kW | Read | |||
| Total apparent power | VA | Read | |||
| Total reactive power | var | Read | |||
| Total Energy Import | kWh | Read | |||
| Total Energy Export | kWh | Read | |||
| Total Energy Import L1 | kWh | Read | |||
| Total Energy Import L2 | kWh | Read | |||
| Total Energy Import L3 | kWh | Read |
Loading registers…
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor per-phase voltage, current, and power on a live cloud dashboard for each tenant or load group.
- Create an alert when total active power exceeds a contractual demand limit for more than five minutes.
- Log cumulative energy import and export values for monthly billing or energy audit reports.
- Compare energy consumption across multiple WAGO meters installed in different distribution boards.
- Track grid frequency and reactive power to identify power quality issues in commercial buildings.
Installation
Mount the WAGO 879 meter on the DIN rail and wire the voltage and current inputs according to the meter installation manual.
Connect the Modbus RTU A and B terminals of the meter to the corresponding RS-485 terminals on the ModbusCloud Gateway.
Set the Modbus slave address on the WAGO meter using the front-panel buttons or DIP switches, and note the address for template configuration.
Verify the meter is configured for 9600 baud and odd parity, which are the default settings matching this template.
Import the WAGO 879-3020 template in the ModbusCloud platform and assign the correct slave address to the device.
Power on the gateway and confirm that live readings such as voltage and frequency appear on the ModbusCloud dashboard.
Things to watch for
Which baud rate and parity settings does this template expect?
The template is configured for 9600 baud with odd parity (1 stop bit). These are the factory defaults on WAGO 879 meters. If you have changed the meter settings, reconfigure them to match or adjust the gateway port settings accordingly.
Do I need to change the template when using a 879-3000 or 879-3040 instead of the 879-3020?
No. All three models (879-3000 4PU, 879-3020 4PS, 879-3040 2PU CT) share the same Modbus register map. The template works without modification for any of these variants.
Why are energy counter values not updating?
Energy counters start at register address 24588 and use float32 format. If values remain at zero, verify that current is flowing through the meter and that the CT orientation is correct on the 879-3040 model.
What byte order do the float32 registers use?
WAGO 879 meters use big-endian (AB CD) byte order for float32 registers. The template is preconfigured for this byte order. If you see unrealistic values, confirm that the byte order setting on the gateway matches.
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