Building Automation with HVAC Library for CODESYS©

Comfortable and Hardware-independent programming


CODESYS® control with interfaces (RS232 / 485 / CAN) and integrated I / Os that can be extended with external Modbus RTU I / O units or interfaces. Including finished HVAC libraries as well as many HTML5 visualization elements for CODESYS®.

We develop modules for the Codesys development environment.

Advantages of HVAC by Pfänder

Comfortable programming of Heating Ventilation and Air Conditioning systems
Ready-to-use FBs and visualization macros with HTML5
Hardware-independent (PLCs/IOs)
Training and technical support
Fast and efficient

Software offered by HVAC

HVAC Building & Process Automation SL

90,00 €

HVAC (Heating Ventilation and Air-Conditioning) Functional components and HTML5 visualisation.
Automate and visualise your entire building technology professionally and independently of hardware: ventilation systems, heat generation, heating circuit distribution, individual room control, room automation, light and blind control

Without purchasing a license (just download), the HVAC Library SL runs for 30 minutes without functional limitations and disconnects automatically (demo).


The HVAC Building & Process Automation SL product contains functional components and HTML5 system macros for creating, for example, heating and ventilation systems but also for room automation and other industrial system technology. There is an added value, above all, in the easy programming and the hardware independence of controllers and EA groups. Extensions such as, for example, MySQL Library, EA drivers and more allow the user a modular coverage of the requirements. The product portfolio is always being expanded with new functions, products and communication links of common bus systems. Extensive training sessions, support and individual service provisions for software creation complete the offer.
Benefit from 30 years of experience in building automation: Development, closely associated with practice, of this library is our aspiration.

Decide for yourself on which controller to run your application - simple, inexpensive automation tasks on a Raspberry Pi with full functionality or professional, fail-safe automation tasks on other controllers - industrial PC or a controller of the 350 producers from the CODESYS device directory.



MySQL Library SL

70,00 €

This Library allows you to connect your CODESYS v3.5 application to a MySQL-Sever database to read and write data from it.

Without purchasing a license (just download), the MySQL Library SL runs for 30 minutes without functional limitations and disconnects automatically (demo).


This Library allows your CODESYS v3.5 application, to connect with a MySQL-Server database. It gives you the opportunity to read and store process data to an external or internal MySQL database, without any 3rd party software or driver. Whether you want to store data for long-term logging, exchange data with 3rd party applications or collecting a mass of machine data for your next IoT project, it’s all possible with our MySQL-Library for CODESYS.
You will be able to connect to a MySQL-Server, which is directly running on the same system, as your PLC (local) or you can also connect to a remote hosted MySQL-Server, anywhere in the world.

MySQL is a fast, easy-to-handle, and lightweight database system and compatible with most of the well-known operating systems.


Supported MySQL-Commands


Database entries can be executed by hand or with a trigger. The runtime speed is depending on the MySQL-Server, connection speed, and runtime system. There are a lot of examples available, how you can use the library.


Example Project

MySQL example

Romod I/O Modules SL

50,00 €

This library allows you to use Romod I/O devices from the manufacturer Romutec ( via RS485 COM-Port on supported CODESYS PLC runtimes. The devices can be easily added to the device tree. The configuration of module-specific parameters is done under the device parameters tab, without any programming requirements. All input/output variables can be mapped in the I/O-Mapping section.

Without purchasing a license (just download), Romod I/O Modules SL runs for 30 minutes without functional limitations and disconnects automatically (demo).





This library allows you to use the Romod I/O modules 16DI, 8DO, 8DO-R, 4DO-R, 8AI and 8AO with supported CODESYS PLC runtimes. It requires an RS485 COM-Port interface and also a Modbus license (mostly included).
The devices can be added to the device tree and also be extended with various romod modules. Variables can be mapped to the program under the I/O-Mapping Tab.

All output modules are local override/indication devices; the state can be monitored and changed. If the device is local overrode/indicated, then it will be shown under the device tree.

There is also a parameter settings window for each module. Different settings as slave-address, Bus-Timeout, send command or cycle request time can be configured under this section. Many specific I/O extended settings are also available for example Negation, two-point-function, limiter, damped function etc. The analog input module allows you to select sensors as PT1000/100, Ni 1000, NTC 10k, etc.
The Romod-Master device is required for configuring the physical hardware COM-Port. Common serial settings can be configured there.

The Hardware modules can be decentral installed (for example in electrical distribution boards). Supported bus cable length for the devices is up to 3937 feet (based on the environmental conditions). Each device address is configurable with dip switches. Serial communication settings as baudrate don’t need to be configured because the devices are supporting “Autobauding”. This feature is decreasing the fault-rate and also the installation time out of the field.

Please note: The modules don’t support real-time requirements.



General Functions

  • Outputs are head-on optimized
  • Cycle request time settable for each input module
  • SafeState: Analog and digital state on bus error (Timeout configurable)
  • Module commands can be sent by bus control (for example factory reset)
  • Request of romod module ID and module firmware
  • Optimized Bus-Watchdog in case of slave interruption

16DI Module

  • Each digital input can be negated under the parameter window
  • Input detection also on delayed bus request

8DO and 8DO-R Module

  • Each digital output can be negated under the parameter window
  • Shows dip switch position: (A)uto (O)ff (O)n

4DO-R Module

  • Each digital output can be negated under the parameter window
  • Configurable press time for hardware button
  • Switching delay between the outputs can be set
  • Shows dip switch position: (A)uto (O)ff (O)n
  • Reset automatic mode from bus control
  • Manual mode can be disabled

8AI Module

  • Input configuration selectable based on sensor/function and deposited curve:
    - 0..10 Volt
    - Resistor 0..5 kOhm
    - Resistor 0..10 kOhm
    - PT100/PT1000
    - Ni1000
    - Ni1000 Landis+Gyr
    - KTY 81-110
    - KTY 81-210
    - NTC 20k
    - NTC 10k
  • Configurable delta value (request only change between the delta value)
  • Integrated two-point-function
  • Offsetvalue (sensor value correction)
  • Integrated limiter with min and max range. In case of exceeding/falling below the analog value can get the value as configured, for example; Input, minimum, maximum, replaced value or last value. Also, the error flag will be set to true.
  • Integrated filter with built-in time constant
  • In the I/O section, the raw value and the processed value is shown

8AO Module

  • Configurable Change-Area
  • Safestate for output value in percentage
  • Shows dip switch position with poti value


Romod state view

Dweet Pro Library SL

50,00 €

This is an unofficial library for use with the and service. It’s developed to use with the main features as sending and receiving dweets. The library supports a secure connection between the service and the PLC controller. TLS encrypts all traffic. The dweet service also offers the opportunity to protect your “Thing” with a secret key.

Without purchasing a license (just download), the Dweet Library SL runs for 30 minutes without functional limitations and disconnects automatically (demo).


With this library, you can start your IoT Project within minutes. You can send your data from the field to the cloud or request it. There is no 3rd Party software installation required. The communication is directly established with the Dweet Pro or Dweet Service; both are acting as a cloud gateway. 

Each PLC needs to be registered as a “Thing”. So it’s possible to communicate with different “Things”, no matter if it’s a PLC or other device. Data is exchanged in the open-standard format JSON. So you can integrate the data easily to existing software products. 

The product is coming along with a detailed documentation and a Quick-start guide ( So you can start to use this library together with the dweet service within a really short time. The library can be tested without any fees!  



Establish an industry secure connection between your PLC and the dweet Pro cloud service with TLS. The whole data connection from your PLC to the dweet service is completely encrypted.


There are several options, to configure alerts directly in the cloud. Set Real-time notifications that keep you informed. It’s possible to set up E-Mail alerts directly from the Dweet Pro Cloud. Data can also be used to configure SMS or text-to-speech messages from another cloud providers.


Store data up to one month, without the need of physical storage.


Use cloud services to visualise your data or build it by your own. Connect quickly to and create a cloud visualisation within minutes.


Communicate with devices in different locations.


For data exchange, the open-standard JSON format is used.


Products we are working on

AlarmMessage Tool Library SL

Easily create alarm policies, recipient lists and much more within the visualization. Monitoring of the policies and automatic e-mail transmission with predefined alarms in CODESYS. The library also includes a Visu macro!

For further information please contact us!

Submit request

HVAC Macro Library SL

HVAC macros for use with the HVAC library.

For further information please contact us!

Submit request

HVAC Features Library SL

Extension of the HVAC library with help modules for various conversions as well as simple SEND and RECEIVE modules for communication between CODESYS controllers.

For further information please contact us!

Submit request

EnOcean Library SL

Simple programming of EnOcean subscribers; requires a supported EnOcean gateway.

For further information please contact us!

Submit request

KNX Library SL

Transmission and reception of group addresses in an existing KNX network in combination with a supported KNX TCP gateway.

For further information please contact us!

Submit request

M-Bus Library SL

Supports the function of querying M-Bus subscribers directly from CODESYS. Requires a supported M-Bus Gateway.

For further information please contact us!

Submit request

MP Bus Library SL

Communication with MP Bus devices of the company Belimo directly from CODESYS. Requires a supported MP Bus Gateway.

For further information please contact us!

Submit request


Technical Training

We offer individual technical-trainings for your team at your office or at our facilities.
Courses are held in small groups, and the content of the courses are deepened with examples.

Some contents are; Working with the CODESYS Development environment, How to use the HVAC-Library or training and support in individual macro and library creation.

We also support you with on-site appointments.

Contact us!


To get easily started, we also offer you an documentation section and a Youtube Channel. There are some Step-to-Step Guides to get started with.

The offer is constantly being extended!





Consulting / Support

We are committed to software products with detailed documentation and support. Therefore, in addition to the documentation of the individual components in the CODESYS library, we have also created an online wiki and YouTube videos. This provision is constantly expanding!

Start with personal consulting instead of the „Trial and error“ method! We offer you a remote consulting solution to start your project efficient. Questions can be directly answered by reviewing the project source code from your desktop. You only get charged for the time we need for solving the problem or answering your questions.

Simply buy a support ticket via the PayPal button and get in touch with our developers. It is envisaged that the joint processing of a ticket will basically require a time frame of 1 hour. We are also happy to make you an offer - you can then easily pay against invoice.


Buy support ticket:

Training „CODESYS and HVAC Basics“


Take advantage of our free basic training! We will show you in a websession how you can program with CODESYS and our HVAC library. Together we thus create small programs and HTML 5 visualisations.At the end, we will parameterise controllers at the in-house complete air conditioning RLT facility and make changes! Use the expertise of our programmers to answer your questions - we look forward to seeing you. For you, participation is completely free!

Custom Solutions

Solutions perfectly tailored to your needs


Do you have special requirements or individual needs? But you don’t have enough resources or a deficit in knowledge to handle it? Then we’re the partner you’re looking for! Our experienced software developers will support you in realising your project. 

Obtain a quote

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oder Tel. 07958 - 9800-0