Product description

Modbus RTU to analog signal converter | 3 outputs 0-10VDC/0-20mA/PWM | 24VDC PoM | DIN rail | IP20 | Sentera Controls | DDACM-03

DDACM-03 – a Sentera Controls converter that turns a Modbus RTU (RS485) command into three analog 0-10 VDC, 0-20 mA or PWM output signals. This allows a BMS or Sentera controller to control, via Modbus, devices that understand only an analog signal – e.g. EC fans, actuators, frequency converters.

Key idea:
The converter is a bridge between digital automation and "analog" equipment: there is no need to replace an EC fan or actuator just because it has no Modbus – it is enough to write a value to a register.

Outputs
3 × 0-10 VDC / 0-20 mA / PWM

Control
Modbus RTU (RS485) – holding registers

Power supply
24 VDC PoM, Imax 50 mA

Installation / protection
DIN rail, IP20

Operating principle

The converter is mounted on a DIN rail and plugged into the Modbus RTU line with an RJ45 connector, over which it also receives its 24 VDC supply (Power over Modbus, Imax 50 mA). The mode of each output O1–O3 is selectable: 0-10 VDC (min. load 50 kΩ), 0-20 mA (max. load 500 Ω) or 1 kHz PWM (open collector with an external resistor and a 3.3–30 VDC source, or a 12 VDC level).

The master unit – a Sentera RDPU controller or any BMS module capable of writing to Modbus holding registers – writes the desired value, and the converter reproduces it at the outputs: 0-10 VDC accuracy ±0.1 V, 0-20 mA – 0.1–0.2 mA, PWM pulse width <0.1 %. The DDACM-03 outputs are not isolated; when the controlled equipment has a different supply potential, choose the DDACM-I3.

Result – three analog devices (EC fans, actuators, frequency converters) are controlled from a Modbus system without an additional PLC. Parameters are monitored and changed with the 3SModbus software or the Sensistant Modbus configurator, the firmware is updated via Modbus RTU, and the status is shown by 3 LED indicators.

Benefits DDACM-03?
Allows analog equipment to be controlled from a Modbus system without additional controllers and without long analog cables throughout the building.

Technical specifications

Product type	Modbus RTU to analog signal converter
Manufacturer / code	Sentera Controls / DDACM-03
Series	MDACM1 (1 output) / DDACM-03, DDACM-I3 (3 outputs)
Power supply	24 VDC via Modbus (PoM), Imax 50 mA
Analog outputs	3 (O1–O3), 0-10 VDC / 0-20 mA / PWM
0-10 VDC output	min. load 50 kΩ
0-20 mA output	max. load 500 Ω
PWM output	1 kHz, min. load 50 kΩ; open collector (external resistor and 3.3–30 VDC source) or 12 VDC level
Galvanic isolation	No
Accuracy	0-10 VDC ±0.1 V; 0-20 mA 0.1–0.2 mA; PWM pulse width <0.1 %
Communication	Modbus RTU (RS485), RJ45 (PoM)
Configuration	3SModbus software, Sensistant Modbus configurator; firmware update via Modbus RTU
Indication	3 LED status indicators
Installation	DIN rail
Protection class	IP20 (EN 60529)
Operating environment	-10…+60 °C, 5–85 % rH non-condensing
Weight	0.076 kg net
Compliance	EMC 2014/30/EU, WEEE 2012/19/EU, RoHS 2011/65/EU, LVD 2014/35/EU

Manufacturer documentation

✔ Recommended by Elektrotechnikos sprendimai

Original manufacturer documentation – technical data, wiring diagrams and installation instructions.

Main functions

Selectable output type – 0-10 VDC, 0-20 mA or PWM – suitable for EC fans, actuators and frequency converters.
3 independent outputs – one module controls, e.g., the supply and extract fans and a damper actuator.
Power over Modbus – 24 VDC and data over a single UTP cable – no separate power supply needed at the transmitter.
Control via registers – the master controller or BMS simply writes the value to a holding register.
Update over the network – firmware is updated over Modbus RTU.
3 LED indicators – the status is visible on the panel without a computer.
Configuration via 3SModbus / Sensistant – output modes and parameters are changed with free software.

Where is it used?

EC fan control from the BMS via Modbus
Control of actuators, valves and dampers with a 0-10 VDC / 0-20 mA signal
Analog speed setpoint for frequency converters
Sentera RDPU controller systems with analog equipment
Retrofit where older equipment has no Modbus
Heat recovery unit automation: supply and extract fans and the bypass damper
Group control of damper and valve actuators from a single panel

On-demand operation

For heat recovery unit manufacturers.
Three non-isolated outputs in a single DIN module – economical control of fans and a damper from Modbus.

For the BMS integrator.
Analog equipment is controlled simply by writing to holding registers, with no additional PLC.

For HVAC automation panel manufacturers.
A compact module powered via PoM that replaces three separate transmitters.

Practical application

If the supply and extract EC fans and the bypass damper actuator of a heat recovery unit are controlled with a 0-10 VDC signal, then a single DDACM-03 with outputs O1–O3 controls them all from BMS registers, drawing only up to 50 mA from the 24 VDC PoM line.

Application guide: how it is used in practice

DDACM-03 always receives its command via Modbus – only the equipment connected to the output differs:

Site	What is connected	Result	Installer's note
Supply / extract EC fan	EC fan 0-10 VDC input → output (0-10 VDC mode)	Fan speed controlled from the BMS or RDPU	Check that the load is ≥50 kΩ
Damper or valve actuator	Actuator 0-10 VDC or 0-20 mA input → output	The position is changed with a Modbus command	In 0-20 mA mode the load must not exceed 500 Ω
Frequency converter	Converter analog speed input → output	Pump or fan speed from the BMS	When the transmitter potentials differ – choose DDACM-I3
Equipment with a PWM input	PWM 1 kHz output (open collector or 12 VDC)	Control by PWM signal from Modbus	An open collector requires an external resistor and a 3.3–30 VDC source

How to choose a signal converter

Task	Recommended model
Modbus → 1 analog output, surface mounting, IP65	MDACM1 (1 × 0-10 V / 0-20 mA / PWM)
Modbus → 3 analog outputs, DIN rail	DDACM-03 (3 outputs, non-isolated) ← this model
Modbus → 3 galvanically isolated outputs, DIN	DDACM-I3 (3 isolated outputs)
8 analog inputs → Modbus, DIN	DADCM-08 (4 Ai/Di + 4 Ai)
4 analog + 4 temperature (PT500/PT1000) inputs → Modbus	DADCM-44 (4 Ai/Di + 4 Ti)

Rule: count how many analog signals need to be controlled at one point: 1 – MDACM1 (IP65, at the device), 2–3 – DDACM-03 in the panel; if the controlled equipment is powered from another source or there is a risk of interference – DDACM-I3 with galvanically isolated outputs. To read analog signals onto Modbus use the DADCM series.

When to choose another solution: for reading analog sensor signals onto Modbus – DADCM-08 / DADCM-44; for digital signals and relays – DIO-M-D4 / DIO-M-R2.

Pros

0-10 VDC / 0-20 mA / PWM in one
Power over Modbus (PoM)
Configuration with the 3SModbus software
Firmware update over the network
3 outputs in one module
DIN rail

Cons / limitations

A master Modbus device (RDPU, BMS) that writes the registers is required
Has no control logic of its own – it only converts the signal
IP20 – panel only; right next to the equipment, mount the IP65 MDACM1
Outputs are not isolated – for isolation choose DDACM-I3

Safety and installation notes

Installation and connection are to be carried out by a qualified electrician or automation specialist with the power disconnected.
Do not exceed the power of the Power over Modbus (PoM) supply – add up the currents of all devices powered on the line.
Do not exceed the output load limits: 0-10 VDC ≥50 kΩ, 0-20 mA ≤500 Ω.
Use in an environment of -10…+60 °C, 5–85 % rH, non-condensing.

Quick selection guide

Modbus RTU

3× 0-10 VDC / 0-20 mA / PWM

24 VDC PoM

IP20

DIN

Suitable when you need:

to control an EC fan, actuator or frequency converter from a Modbus system;
to avoid long analog cables across the building;
to connect analog equipment to a Sentera RDPU or BMS.

Check before use:

the input type (V, mA or PWM) and the load of the controlled equipment;
how many outputs are needed at one point;
whether the system has a master Modbus device that writes registers.

Important reminder: The DDACM-03 is not a controller – its output value is set by the BMS, a Sentera RDPU or another master Modbus device.

FAQ

What determines the output value?
The value is written to the holding registers by the master Modbus device, for example a Sentera RDPU or a BMS controller.

Can an EC fan be controlled?
Yes, via the 0-10 VDC or PWM output, if the fan has such a control input.

Is a separate supply required?
No, the transmitter is powered with 24 VDC over Modbus (PoM) via the RJ45 cable and draws up to 50 mA.

Can a different signal be selected for each output?
Yes, the mode of each output O1–O3 (0-10 VDC, 0-20 mA or PWM) is selected individually.

What output load is permitted?
A 0-10 VDC output requires a load of at least 50 kΩ, while the load of a 0-20 mA output can be up to 500 Ω.

What is the difference between DDACM-03 and DDACM-I3?
The DDACM-I3 outputs are galvanically isolated (630 VDC working, 1000 VDC for one minute), while the DDACM-03 outputs are not isolated.

Modbus RTU to analog signal converter | 3 outputs 0-10VDC/0-20mA/PWM | 24VDC PoM | DIN rail | IP20 | Sentera Controls | DDACM-03

Sentera DDACM-03 – a Modbus RTU to analog signal converter: 3 outputs 0-10 VDC / 0-20 mA / PWM, 24 VDC PoM, IP20, DIN rail mounting – for controlling EC fans and actuators from a BMS.

Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.

Attributes

Manufacturer

Sentera controls

CE certificate – a guarantee of safety, quality, and compliance

This product is marked with the CE label, which confirms that it complies with all applicable European Union directives and regulations. CE marking is not just a formality – it is an important indicator of quality and safety, ensuring that the product has been properly assessed, tested, and can be safely used throughout the EU market.

CE certification means that the product has been evaluated according to the main criteria:

Safety requirements – ensures that the product does not pose a risk to the user or the environment
Electromagnetic compatibility (EMC) – the device does not interfere with other equipment and is resistant to external disturbances
Environmental standards – complies with current ecological and material usage requirements
Operational reliability – the product is suitable for long-term use according to its intended purpose

CE marking allows this product to:

be legally supplied and used in all European Union countries
ensure a high level of quality and safety
be used in residential, commercial, and industrial environments

The CE mark is a declaration of the manufacturer’s responsibility, confirming that the product complies with all applicable standards and has been assessed according to EU legislation.

What does this mean for you as a buyer?

Safe use in everyday activities
Reliable performance and reduced risk of failure
Compliance with EU standards and requirements
Suitability for professional solutions

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Products catalog

Product Catalog

Modbus RTU to analog signal converter | 3 outputs 0-10VDC/0-20mA/PWM | 24VDC PoM | DIN rail | IP20 | Sentera Controls | DDACM-03

Modbus RTU to analog signal converter | 3 outputs 0-10VDC/0-20mA/PWM | 24VDC PoM | DIN rail | IP20 | Sentera Controls | DDACM-03

Operating principle

Technical specifications

Manufacturer documentation

Main functions

Where is it used?

On-demand operation

Practical application

Application guide: how it is used in practice

How to choose a signal converter

Pros

Cons / limitations

Safety and installation notes

Quick selection guide

FAQ

Modbus RTU to analog signal converter | 3 outputs 0-10VDC/0-20mA/PWM | 24VDC PoM | DIN rail | IP20 | Sentera Controls | DDACM-03

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