I see zero values for energy and volume. What could be wrong?

Energy and volume are stored in 32-bit registers spanning two consecutive addresses. Verify that your gateway is reading both registers as a single 32-bit value. A register offset mismatch can also cause this. Check the slave address and confirm the Faun is powered and responding.

What baud rate and parity should I use?

The Apator Faun uses 9600 baud with even parity (1 stop bit). Make sure the ModbusCloud gateway serial port is configured to match these settings exactly. A mismatch will result in communication timeouts.

Can I write setpoints or control the Apator Faun via Modbus?

No. The Apator Faun only exposes read-only registers. This template is monitoring-only and does not include any writable registers.

Temperature readings seem unusually high or incorrect. How do I fix this?

Temperatures are provided as uint32 values in degrees Celsius. Check that the register data type is set to uint32 and not uint16. If you have customised the template, verify the register addresses match the Faun documentation for your firmware version.

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Free Modbus template: Apator Faun | ModbusCloud

///Apator Faun

Modbus RTU

Apator Faun

Name: Apator Faun
Brand: Apator
SKU: a4c105f2-63d4-44f9-b3bd-40c0fb73fcfc

Apator

Monitors heat meter energy, temperature, and flow data via Modbus RTU.

Overview

The Apator Faun is an electronic calculator for heat meters used in heating and cooling installations. This Modbus RTU template reads energy consumption, flow and return temperatures, volume, flow rate, and instantaneous power. It is suited for monitoring heat distribution in residential, commercial, and industrial buildings.

Key readings

Main Energy (kWh)
Flow Temperature
Return Temperature
Main Volume (m3)
Instantaneous Flow Rate
Instantaneous Power (kW)

Use cases

Monitor main energy consumption in kWh on a live cloud dashboard for billing verification.
Track flow and return temperatures over time to evaluate heating system efficiency.
Create an alert when the temperature differential between flow and return drops below a threshold.
Log instantaneous flow rate and power to detect abnormal load patterns in heat distribution centres.
Generate monthly energy and volume reports for building managers or energy consultants.
Compare heat meter data across multiple buildings in a single ModbusCloud project.

Installation

1Wire the Modbus RTU connection (A and B terminals) from the Apator Faun to the RS-485 port on your ModbusCloud gateway (MCG or MLP series).
2Set the Apator Faun Modbus slave address to a unique value on the bus and note the address for gateway configuration.
3Confirm the Apator Faun serial settings: 9600 baud, even parity (matching the template defaults).
4In the ModbusCloud portal, add a new device and import the Apator Faun template from the template library.
5Enter the configured Modbus slave address in the device settings and verify communication by checking live register values.
6If multiple devices share the same RS-485 bus, ensure each has a unique slave address and proper bus termination.

Things to watch for

I see zero values for energy and volume. What could be wrong?: Energy and volume are stored in 32-bit registers spanning two consecutive addresses. Verify that your gateway is reading both registers as a single 32-bit value. A register offset mismatch can also cause this. Check the slave address and confirm the Faun is powered and responding.
What baud rate and parity should I use?: The Apator Faun uses 9600 baud with even parity (1 stop bit). Make sure the ModbusCloud gateway serial port is configured to match these settings exactly. A mismatch will result in communication timeouts.
Can I write setpoints or control the Apator Faun via Modbus?: No. The Apator Faun only exposes read-only registers. This template is monitoring-only and does not include any writable registers.
Temperature readings seem unusually high or incorrect. How do I fix this?: Temperatures are provided as uint32 values in degrees Celsius. Check that the register data type is set to uint32 and not uint16. If you have customised the template, verify the register addresses match the Faun documentation for your firmware version.

Registers (6)

6 read / 0 write

Name	Address	Function	Type	Unit	Access
Main Energy Main Energy	1030	FC03	uint32	kWh	R
Flow temperature Flow temperature	1062	FC03	uint32	°C	R
Return temperature Return temperature	1064	FC03	uint32	°C	R
Main Volume Main Volume	1044	FC04	int32	m³	R
Instantaneous flow rate Instantaneous flow rate	1542	FC03	uint16	m³/h	R
Instantaneous power Instantaneous power	1538	FC03	uint16	kW	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.

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Specifications

Protocol: Modbus RTU
Brand: Apator
Registers: 6
Compatible models: Apator Faun
Last updated: 2 April 2026

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