Laboratory stand for designing industrial KNX networks on Siemens logo! Communication modules

. Industrial automation networks based on the EIB / KNX protocol are very popular among European companies in the construction of intelligent buildings, but they are of little interest in high school education and currently professional specialists are not trained to use them. Developing the KNX‐based automation system simulator for the training of engineering students is required. We have designed and installed a KNX simulator for engineering students training on smart systems. The presented stand was developed on Siemens LOGO! Basic with CM KNX communication modules. The modules of simulator and KNX software programming tool ETS are explained. Besides, sample scenarios for engineering students to enhance and implement their projects are given.


Introduction
When building smart energy systems, it is necessary to choose a method of data exchange between control and executive elements (controllers, relays, etc.). In this case, AS-i, ProfiNet, ModBus [1], KNX / EIB, LonWorks [2] and other protocols are usually used. Among these protocols, the KNX protocol is preferred thanks to its some specifications such as easy and fast installation, user-friendly software, and adaptation to the existing system.
In high school education, little attention is paid to building industrial networks based on these modern protocols [3]. An intelligent building management system typically includes [4]: − lighting control -by motion sensors, light level or timers; − adjustment of illumination (dimming) [5]; − heating by temperature, time or occupancy sensors; − ventilation by indicators of air sensors or the presence of gas [6]; − automatic gates, shutters, electric pumps; − perimeter security in the house and intrusion detection [7]; − alarm (sound, light) in case of alarm; − power outlets; − fire protection by the presence of smoke or fire; − protection against water leaks; − information board for indication and management; − weather data; − energy saving due to electricity and water metering.
The EIB / KNX system assumes the fulfillment of all the above functions [8]. This simplifies the cable systems of the building, their design and installation. The EIB system has great flexibility: expansion and change of functions are achieved by rearrangement, addition or reprogramming of components [9].
Selection of Siemens LOGO! Basic is determined by their availability, a wide range of functions and the availability of communication capabilities.

Methods
The KNX standard based on EIB has been actively developed over the past years and is approved by the international organization «KNX Association» as ISO / IEC 14543 [10]. Its advantages [11] are expressed in a distributed decentralized architecture that does not require a central control device / computer, the use of different topologies (common bus -a two-pair lowcurrent cable, star, tree), distance ranges (up to 1000 m), support for various data transmission media (twisted pair, power line, radio channel), baud rate (9600 baud), event control (the master sends a telegram -the slave makes an acknowledgment) and speed (20 ms) [12]. Some disadvantage of KNX is its low fault tolerance -in the absence of acknowledgment (confirmation), data transfer is stopped and must to be repeated, i.e. it cannot be used in applications related to danger to people.
Siemens LOGO! Controllers are industrial and meet all electrical safety standards. Logo! Basic 24RCE has an output relay capable of controlling power devices up to 10A. 38 built-in functions are programmed using the Siemens Soft Comfort software with visual simulation.
LOGO! Communication Module CM EIB / KNX has 24 virtual digital inputs and 16 outputs, as well as 8 analog water and 2 outputs. CM modules can operate as master and slave devices.
Parameterization of the modules is carried out using the KNX ETS software (Engineering Tool Software). The software allows to organize centralized equipment management throughout the entire building automation project. While almost all smart home systems are tied to the manufacturer [13], KNX ETS is an open and extensible system that allows to combine a wide range of devices from different suppliers, adding new sensors and actuators as needed. ETS5 software contains a built-in database of KNX equipment from leading manufacturers ABB [14], Gira, Schneider Electric, Zennio and others, which allows you to build real projects. About 10 thousand KNX devices include: relays (including control of curtains, blinds, gates), dimmers (dimmer), buttons and switches, binary and analog inputs and outputs, sensors (movement, light, temperature, power consumption, weather, water, smoke, gas leaks), climate control (heating, ventilation, air conditioning), touch panels, bridges to other systems (IP, DALI, SMS, phone, email, intercom, security systems), system components (power supplies, bridges, programming interfaces, controllers) [15,16].
Structurally, the stand (Fig. 1) is a stand mounted on a laboratory bench. The stand is portable and can be mounted on any suitable laboratory  − light sensor: when exceeding a certain brightness limit, closing the blinds, lifting the blinds in the dark. − a timer that weekly centrally controls the temperature profile of the room, turning off the lighting at night.

Results
As a result of solving the test example, we obtain the following configuration. For each room: − 1 x 3x dimmer / dimmer with integrated dimmer − 0.25 x 8-fold shutter drive − 1 valve actuator with 2 integrated contact inputs − 1 heating controller with integrated 2x button − 1 x 4x button − 1 display with at least 8 display and control functions − 1 logic module for converting analog thresholds to binary signals (gate) − 1 logic module for all binary connections for group signals − 1 weather control unit − 1 time master (since the functions of the clock can also be detected by an analog threshold generator when it receives time on a regular basis).

Conclusions
To document the project, ETS creates a series of reports Information about the device, that is, the configuration of flags, flags of objects, comments and assigned addresses, should not be printed out in the form of a building, but in the form of a detailed line.
The commissioning of the KNX installation does not necessarily require a complete setup of the shared bus installation with all devices. Since the complete data set is not absolutely loaded onto the bus coupler at the commissioning stage, it may be useful to load only the individual addresses into the bus couplers and the remaining relevant data. Regardless of whether commissioning is carried out on a breadboard or on a construction site, flush-mounted application modules must not yet be installed, so that the programming button and programming LED remain accessible. In switchboards, it is necessary to remove the covers so that for these KNX devices the programming button and LEDs remain accessible. In the case of built-in devices in suspended ceilings or fixtures, it is advisable to assign them their individual address before installation, since such devices are usually available only with great effort after installation.
The goals of commissioning and diagnostics are as follows: − Download -opens the download menu for individual addresses and programs; − Download individual address -download an individual address; − Download the application -downloads the application program; − Reset -sends a restart command to the bus device; − Unload -resets the device that has already been commissioned to its original state; − Information -reads information about the device; − Diagnostics by individual address -checking existing bus devices in the installation for compliance with the project. After testing the project on the basis of a laboratory stand, students receive the necessary amount of knowledge and practical skills in the design of industrial KNX networks. Further development of the project is seen in the use of mobile devices on Android / iOS [19] and in Internet Of Things (IOT) [20] to control smart energy systems.