Mervis software platform - the officially supported solution for programming Unipi programmable logic controllers.

Complete solution from a control program to a local web interface to SCADA interface including a mobile app - all of this available in the Mervis system


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What is Mervis?

Mervis is a full-fledged software platform provided for free for all Unipi controllers. It is a professional solution suitable for a wide range of applications, from smart home control to industrial automation. The Mervis IDE development environment, a core of the whole platform, is suitable for both beginners and experienced programmers due to its user-friendly interface and comprehensive design.

Detailed info about Mervis, its parts and functions, is available on this link. 

What is the licence needed for?

The licence request contains a licence code for the Mervis Runtime - a software running directly on the Unipi PLC which executes programs created in the Mervis IDE development environment and is thus necessary for a proper function of Unipi controllers using Mervis. Without the licence, Mervis Runtime will run only for 20 minutes from the start of the PLC or its control logic. During this trial period, you can freely test all functions of the Mervis IDE. After the trial period expires, Mervis Runtime will deactivate and the control logic will stop. Full functionality can be restored by successfully licencing your controller. The licence is applicable only for Unipi hardware, eg. it cannot be used on standalone Raspberry Pi computer.  A complete Runtime licencing tutorial is available on this link.

By using the licence request, you will also obtain login credentials for the Mervis DB service (storing the historical variable value from PLCs) and identification code for the Mervis Proxy service (secure remote access to controllers). Licence activation guide is available on this link. 

Note: The licence request will be sent to you via the e-mail address used for registration on the Unipi e-shop. 

Information for existing Mervis users

The new licencing system applies only to Mervis IDE v2.3.0. If your projects use the Mervis IDE 2.2.0 or older, you do not need to perform any changes. Licencing must be performed only when transferring your project to the Mervis IDE 2.3.0 - in that case, all you need to do is to licence Mervis Runtime using your already obtained licence cards. 

Mervis allows you to: 

  • create and debug control programs for PLC in a user-friendly Mervis IDE development environment
  • create and edit web user interfaces for comfortable control of your system
  • communicate with your controllers remotely from anywhere through a secure remote access
  • monitor and analyze your historic data using a professional SCADA interface
  • monitor your system through a mobile app in your smartphone or tablet 

Mervis platform components

Mervis IDE

A development environment for creating, debugging and remote management of control programs for Unipi controllers. The Mervis IDE supports two IEC 61131-3 compliant programming methods for creating controller behaviour. 

Functions block (FUPLA)

FBD (or FUPLA) is a programming language based on predefined blocks of code. Each block has its specific function and its inputs (temperature value, switch signal) and outputs (switch command, regulation etc.). The control logic itself is then created in a clear graphic interface simply by connecting the blocks and variables. Mervis IDE features a large library of default function blocks covering an absolute most of all basic PLC operations, such as mathematical functions (sum, multiplication, comparison), control loops (hysteresis, three-way valves), counters, time schedulers and much more. FBD is thus suitable for users without any deeper programming knowledge.

Example of a control program created using the FBD

Structured text (ST)

The ST language is based on a structured text able to express complex functions by only a handful of lines of text code. The ST is useful mainly for experienced users and programming extensive complex projects. ST can be also used to create custom function blocks if needed

An example of a function block written in ST

HMI editor (Human Machine Interface)

Aside from the control logic itself the Mervis IDE also allows you to create graphic user interfaces for local webpages running on your PLC or for the Mervis SCADA service. These interfaces allow you to visualize the status of your system and control all of its functions. For this purpose, the editor features a large collection of switches, indicators, text fields, time schedulers and other elements. The individual elements, each with wide customization options, can be placed simply by drag-and-drop. The editor also supports uploading your pictures or icons. Complete interfaces can be accessed through a computer, tablet or smartphone using only a regular web browser. 

Screenshot of the HMI editor interface 

An example of a simple web user interface

Mervis SCADA

Mervis SCADA (Supervisory Control and Data Acquisition) is a cloud service for remote management, control and analysis of historic data. SCADA gives you the option to monitor and control all connected systems through a clear graphic interface independently on their location. A single supervision centre is thus able to control technologies installed on different continents. The Mervis IDE graphic editor then allows you to create and edit your SCADA visualisation designs.

For more info about Mervis SCADA, please visit this link. 

Visualisation of a connected technology.

Mervis mobile app

The Mervis mobile app will connect your smartphone to your SCADA interface, allowing you to monitor your system, display historic data via graphs, change data point values and more. The app is available for free on Google Play and App Store.

Visualisation of data in the mobile app

Remote access and management (Mervis Proxy)

The Mervis Proxy service gives you the option to access your Unipi controllers from anywhere using a secure internet connection. The service is necessary for using the Mervis SCADA service but is also useful for remote controller programming or data transfer between multiple controllers without the need for VPN, public IP addresses or any other special network setting. 

Mervis Proxy function schematic

Mervis DB cloud database

Mervis DB serves for sending historical variable values from your controller to secure storage in an Unipi datacentre. You can then visualize and analyze your data through the Mervis SCADA interface. If you are not a SCADA user, you can access the data directly in your web browser using the Mervis DB Viewer web interface. If you are interested in storing the data in your on-premise database, get in touch with us at (suitable for projects with over 5000 data points).

Screenshot of a Mervis DB

Mervis Runtime (RT)

Mervis RT is a software running on the controller, which executes the control logic of programs created in the Mervis IDE.

Broad communication protocol support

Mervis supports a wide range of communication protocols, from the standard Modbus protocol to specialized protocols such as BACnet or M-Bus. That gives you the option to extend your project by the integration of devices from other vendors, significantly widening your options. More info about the supported protocols is available on this link..

 List of supported protocols
AMiT DB-Net/IP 1-Wire
BACnet SoftPLC
IEC 62056-21 SSCP
Jablotron 100 SMA-net
M-Bus Hitachi H-protocol

How to obtain the Mervis?

Unipi 1.1 and Unipi Neuron controllers

A Mervis OS operating system image is available for the mentioned products. The image has to be burned onto a memory SD card. Detailed installation guide can be found on this link.

Unipi Axon controllers

Axon PLCs are shipped with the Mervis OS already installed. All you need to do to start programming is to download and install the Mervis IDE.

Mervis IDE + HMI editor

The development environment itself, containing the HMI editor and SCADA visualisation editor, can be downloaded for free from the Unipi Knowledge Base. For the installation guide, please visit this link.

Mervis SCADA

To access the service, simply sign up on the Unipi e-shop and create a new SCADA project in the Account -> Mervis SCADA menu. The service is free for projects including max. 25 data points. If more than 25 data points are used, a monthly fee is charged.

Mervis DB and Mervis Proxy

Identification codes and login credentials for both services can be found in the customer section of the Unipi web. The Mervis Proxy is available for free, while the Mervis DB offers 25 free data points. If more than 25 data points are used, a monthly fee is charged. A tutorial for obtaining a licence for both services is available on this link.  Brief user guides for both services are available on this link.

Licencing and Mervis Runtime trial period

Mervis Runtime is essential for running control programs created in the Mervis IDE. Without licencing, a 20-minute trial period will start upon startup of the PLC or its control logic. During this trial, you can freely explore all Mervis functions. After the trial period expires, the Mervis RT deactivates and stops the program. Full functionality can be restored by successfully licencing your controller - the licencing guide is available on this link.

How to obtain the licence?

Unipi Neuron an Unipi Axon

Unipi Neuron and Unipi Axon controllers have the licence included in the price. You can find the licence code on a paper request card included in the controller's package. 

Unipi 1.1/1.1 Lite

The licence request card can be obtained as part of the Unipi 1.1 or Unipi 1.1 Lite complete sets. For the Unipi 1.1 basic set or stand-alone Unipi 1.1 expansion board, the licence can be purchased separately

Note: The licence is functional only with Unipi hardware, eg. it cannot be used only for a Raspberry Pi computer. 

Further info

Detailed info about all parts of the Mervis, installation guides, tutorials, showcase projects and other useful info is available on the Unipi Knowledge Base. 

If you have any questions, feel free to get in touch with our technical support ( or visit the Unipi community forum.