Building management system

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1 Volume 58, Number 3, 2017 Building management system Marius Maier, Alexandru Păcuraru, Romul Copîndean, Rodica Holonec Faculty of Electric Engineering, Technical University of Cluj-Napoca, Romania Abstract The paper presents a microcontroller application for building management. For control and monitoring, the LabVIEW programming environment was used. Keywords microcontroller ATmega 2560, LabView programming environment, monitoring and control 1. INTRODUCTION A building management system, BMS (Building Management System), is a control system that monitors and controls the electrical and electromechanical systems of a building. Building services can be: heating, ventilation, air conditioning, pumping stations, indoor lighting, access control and security systems [1], [2]. A BMS system is based on a server with a database, a graphical interface software for monitoring and control, sensors connected to a network through a communication protocol that make the data acquisition part and electric motors, actuators and relays, which provides the execution part and the control panel. 2. GENERAL PRESENTATION The block diagram is shown in Figure 1: - Voltage divider, made of two resistors - Current Hall Sensor type ACS712, 100mv/A [3] - Flow sensor, HZ21WA 10Hz/liter [4] - Arduino MEGA development board with ATmega2560 microcontroller [5] - Relays [6] - Electro valve, type CEME ESM 8614 [7] - Fans, [8], [9] - LEDs for indoor lighting [10], [11] - Recirculating water pumps [12], [19] - Drivers for engine control and LED 2.1 Temperature measurement Temperature is measured in several points: - temperature in several rooms - flow and return temperature - heating and cooling temperature - outdoor temperature The measured temperatures are less than 100 O C, the integrated LM35 sensor can be used. The sensitivity is 10mV/ O C, for 100 O C the supply voltage is 1V. To achieve good resolution for analog to digital conversion, the internal reference of the microcontroller will be VRef=1.1V. The temperature is given by the relationship: TT = NN VV RRRRRR = NN 1, (1) where N is the numerical value given by the Analog to Digital converter. Fig.1 Schematic diagram The application contains: - Temperature sensor type LM35 [1] - Light sensor photoresistor type GL5516 [2] 2.2 Circuit for controlling motors and LEDs Transistor command offers the possibility to voltage regulation, pulse width modulation (PWM), but does not provide galvanic separation. This can be solved using a PC817 optocoupler, which can work up to 20kHz [7]. For Pump and Fan control we use MOS-FET n channel transistors, IRF630, and for large consumers IRFZ46N [8], [9]. The command circuit is shown in Figure 2: 2017 Mediamira Science Publisher. All rights reserved

328 ACTA ELECTROTEHNICA operation, heating or cooling and set the room temperature reference for every room or the degree of illumination. Protections used: Fig.2. Consumer command whith MOS-FET and optocouplers.

On the control panel you can see the indicators for level, voltage, current, power, temperature and controls for light intensity, heating, cooling.

2 328 ACTA ELECTROTEHNICA operation, heating or cooling and set the room temperature reference for every room or the degree of illumination. Protections used: Fig.2. Consumer command whith MOS-FET and optocouplers. 3. PROGRAMMING For programming and monitoring, is used the LabVIEW programming environment, National Instruments [10]. The monitoring and control panel is shown in Figure 3. On the control panel you can see the indicators for level, voltage, current, power, temperature and controls for light intensity, heating, cooling. The system can work in two ways: 1) manually when we order the pump, the electrovalves, the heating boiler, the cooler and the lighting circuits depending on the temperatures or the degree of illumination. 2) automatically, when we select the mode of - Interlock between heating and cooling - The pump does not start if at least one of the electrovalve is not running. - The heating boiler when it reaches the maximum temperature stops, but the recirculation pump works. - The cooler heat exchanger has maximum temperature protection. - Warning no mains voltage (230V) Figure 4 shows a diagram for measuring the flow, return, heater and outside temperatures. Fig.4 Temperature mesurement diagram Analog readings are performed by the analog read function, the value is multiplied by 100 to display temperature in Celsius degree. (For 20 o C the sensor will supply a voltage of 0.2V) Fig3 Monitoring and control panel

Volume 58, Number 3, 2017 329 The measurement of voltages and current can be seen in Figure 5. values and obtain a system of 2 equations at wich the solution are the two constants, m and n.

5 Voltage and current measurement diagram The current sensor, ACS712 Hall transmitter [3] [20], delivers a voltage proportional to current and offset from zero.

3 Volume 58, Number 3, The measurement of voltages and current can be seen in Figure 5. values and obtain a system of 2 equations at wich the solution are the two constants, m and n. I1 = a U1 (3) I 2 = a U 2 By replacinf the catalog values [] we obtain: 0 = a 2,5 (4) 20 = a 4,5 By solving the system 4, a=10 and b=-25 are obtained. Relationship (2) becomes: I = 10 U 25 (5) Fig.5 Voltage and current measurement diagram The current sensor, ACS712 Hall transmitter [3] [20], delivers a voltage proportional to current and offset from zero. The current according to the voltage is a linear function offset from zero, of form: I = a U (2) Knowing two values, we can determine the two constants, the slope of the a, and the offset b. We wil write the equation of the right for the two For voltage measurement a voltage divider of 5 was used. Figure 6 shows a diagram for measuring and controlling indoor lighting: Photoresistors were used to measure light. To display the light intensity, the voltage delivered by the photoresist was logged. For light control logic outputs were used 46, 47, 48, 49, 50, 51, 52, 53. Fan control is done with pulse width modulation, PWM on logic outputs 3, 4 and 5. Fig.6 Indoor lighting mesurement diagram

330 ACTA ELECTROTEHNICA The air conditioning command can be seen in figure 8: In this diagram we can see: - reading room temperatures, heater, cooling.

CONCLUZII The benefits of a building management system would be: - an optimal control. - lower maintenance costs. - quick diagnosis.

4 330 ACTA ELECTROTEHNICA The air conditioning command can be seen in figure 8: In this diagram we can see: - reading room temperatures, heater, cooling. - heating and cooling control according to the reference values. - PWM pump, heating and cooling control is performed. - the valves are ordered. 4. CONCLUZII The benefits of a building management system would be: - an optimal control. - lower maintenance costs. - quick diagnosis. - monitoring the temperatures and the consumption of electric and thermal energy. Adding to the microcontroller, Ethernet, WIGI, or GSM modem communication modules can perform remote control and monitoring. Alarms can also be sent. Fig. 7 Fan PWM command Fig. 8. Air conditioning diagram

5 Volume 58, Number 3, REFERENCES 1. Building Management System, Solutions 2. R Copîndean, R Munteanu jr, FM Daradics, Monitoring System for a Domestic House, Acta Electrotehnica 54 (3 4), , LM35 Precision Centigrade Temperature Sensors, Texas Instruments, 4. GL55 Series Photoresistor, SHENZHEN SENBA OPTICAL & ELECTRONIC CO., LTD., 20Photoresistor.pdf 5. ACS712 Current Sensor ICs, Allegro MicroSystems, LLC ICs/Zero-To-Fifty-Amp-Integrated-Conductor-Sensor- ICs/ACS712/ACS712-ACS713-Frequently-Asked- Questions.aspx 6. HZ21WA, Water Flow Sensor, 7. Arduino MEGA 2560, 8. Opto-Isolated 8 Channel Relay Board, &p= CEME ESM 8614, Solenoid valves, CEME Fluid Control Components, Italy, GEFRAN VDI100 - Convertizor de frecvență cu reglarea de tip: VF și Sensorless Vectorial, Ventilator Vents 150MAT, cu jaluzele automate, EAAYASAAEgJEy_D_BwE W Proiector LED - IP65 Lumina Calda, Lampa Aplicata T8 18W 300x600mm Tuburi LED Incluse Lumina Calda, 300x600mm-tuburi-led-incluse-lumina-rececalda/ 14. Pompa recirculare apa electronica FLO 32/6-180, apa/pompa-recirculare-circulatie-apa-electronica-flo PC817 Series, High Density Mounting Type Photocoupler, SHARP, IRF 630, Power MOSFET, VISHAY IRFZ46N, Power MOSFET, International Rectifier, LabVIEW, National Instruments, R. Munteanu Jr., Eva-Henrietta Dulf, C. Feștilă, D. Iudean Power Transducer for DC Circuits, Acta Electrotehnica, vol. 55, number 1-2, A. Cretu, R. Munteanu jr., Dan Iudean, P. Karaisas, V. Vladareanu Quality of Modern Products A Case Study on Smartphones, 2016 International Conference on Production Research Africa, Europe and the Middle East, 4th International Conference on Quality and Innovation in Engineering and Management (QIEM 2016), Cluj-Napoca, Romania, 2016 Marius Maier Faculty of Electrical Engineering, Technical University of Cluj-Napoca, 26-28, G. Bariţiu st., Cluj-Napoca, Romania Marius.Maier@ethm.utcluj.ro Alexandru Mădălin Păcuraru, pacurarualexmada@yahoo.com Romul Copîndean Faculty of Electrical Engineering, Technical University of Cluj-Napoca, 26-28, G. Bariţiu st., Cluj-Napoca, Romania Romul.Copindean@ethm.utcluj.ro

IT.MLD900 SENSORS AND TRANSDUCERS TRAINER. Signal Conditioning

IT.MLD900 SENSORS AND TRANSDUCERS TRAINER. Signal Conditioning SENSORS AND TRANSDUCERS TRAINER IT.MLD900 The s and Instrumentation Trainer introduces students to input sensors, output actuators, signal conditioning circuits, and display devices through a wide range