Reads energy metering data from Wago 3-phase electricity meters via Modbus RTU.
Overview
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.
Key readings
Voltage L1 to L3
Current L1 to L3
Power L1 to L3
Frequency
Total active/apparent/reactive power
Total energy import/export
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
1Mount the WAGO 879 meter on the DIN rail and wire the voltage and current inputs according to the meter installation manual.
2Connect the Modbus RTU A and B terminals of the meter to the corresponding RS-485 terminals on the ModbusCloud gateway (MCG or MLP series).
3Set the Modbus slave address on the WAGO meter using the front-panel buttons or DIP switches, and note the address for template configuration.
4Verify the meter is configured for 9600 baud and odd parity, which are the default settings matching this template.
5Import the WAGO 879-3020 template in the ModbusCloud platform and assign the correct slave address to the device.
6Power on the gateway and confirm that live readings such as voltage and frequency appear on the ModbusCloud dashboard.
Things to watch for
01
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.
02
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.
03
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.
04
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.
Registers (18)
18 read / 0 write
Name
Address
Function
Type
Unit
Access
Voltage L1
20482
FC03
float32
V
R
Voltage L2
20484
FC03
float32
V
R
Voltage L3
20486
FC03
float32
V
R
Current L1
20492
FC03
float32
A
R
Current L2
20494
FC03
float32
A
R
Current L3
20496
FC03
float32
A
R
Power L1
20500
FC03
float32
kW
R
Power L2
20502
FC03
float32
kW
R
Power L3
20504
FC03
float32
kW
R
Frequency
20488
FC03
float32
Hz
R
Total active power
20498
FC03
float32
kW
R
Total apparent power
20514
FC03
float32
VA
R
Total reactive power
20506
FC03
float32
var
R
Total Energy Import
24588
FC03
float32
kWh
R
Total Energy Export
24600
FC03
float32
kWh
R
Total Energy Import L1
24594
FC03
float32
kWh
R
Total Energy Import L2
24596
FC03
float32
kWh
R
Total Energy Import L3
24598
FC03
float32
kWh
R
Working with Modbus in your projects?
ModbusCloud is the hardware-plus-software platform that installers use to monitor, visualise and control Modbus devices from one portal. This template is one of hundreds you can use right away.
