International Journal of Engineering Trends and Technology (IJETT) – Volume 33 Number 7- March 2016
Air Handling Unit using Programmable Logic
Controller
Pooja C. Oswal#1, Shweta A. Raut#2, Supriya V. Shirke#3,Prof.R. A.Jain#4
#
Department of Electronics and Telecommunication engineering
Sinhgad Academy of Engineering, Kondhwa Bk, Pune 411048, India
Abstract—In this paper programmable logic
controller (PLC) is designed to develop an Air
Handling Unit (AHU). The main scope of AHU is to
maintain the air flow in mall or a building. The aim is
to conserve electrical energy by utilizing the available
energy in an efficient manner which would reduce
electricity bills. In this system, sensing devices are
used to sense the number of people inside the mall and
accordingly AHU fans are controlled by the control
unit. A supervisory control and data acquisition
(SCADA) screen is designed to monitor, supervise and
acquiesces the process data in AHU.
fire, the exhaust fan will suck out the smoke n hot air
outside the mall and buzzer will alert the people.
During such emergencies LED strip will direct the
people.
Keywords—AHU (Air Handling Unit), PLC
(Programmable
Logic
Controller),
SCADA
(Supervisory Control and Data Acquisition)
I. INTRODUCTION
Use of microcontroller or microprocessor in building
AHU is complex. So by using PLC, programmer can
easily build any complicated application with many
inputs as well as many outputs. AHU used in malls is
manually operated which consumes lot of energy
which leads to high electricity bills. So by designing a
system using PLC will reduce power consumption as
well as electricity bills.In this system sensing devices
are used to sense no. of people inside the mall
according to which AHU fans will be controlled. In
case of fire, AHU using PLC can handle the situation
by turning OFF all AHU fans and by turning ON
exhaust fan.
II. PROJECT OVERVIEW
Air handling unit for proper control of air flow system
will be using PLC, SMPS, AHU fans, exhaust fan,
backup fan, sensors, buzzer, LED strips, ducts and
battery. The controller PLC will be getting the input
from sensors to control all the outputs of system
including AHU fans, backup fan, exhaust fan, buzzer
and LED strip. Ducts will distribute the air thus
regulating the air flow inside the mall. Sensor at the
entrance will sense the numberof people entering the
mall and sensor at the exit will sense the people
leaving the mall. In case if power supply cuts off
battery will provide supply to backup fan. In case of
ISSN: 2231-5381
Fig.1:Overview of system
III. HOW IT WORKS
In AHU, diffusion sensor at the entrance will sense
people entering the mall. The counter will increment
on each entry. This input will be provided to PLC as a
parameter. This parameter will be processed and
manipulated by PLC according to logic implemented.
PLC will give signals to AHU fans and thus AHU fans
will operate. Diffusion sensor at exit will sense people
leaving the mall and accordingly counter will
decrement. The processing would be done by PLC as
per the program downloaded in PLC. As a result,
switching OFF of fans will take place. At the time of
fire, all AHU fans will switch off and exhaust fan will
turn ON automatically. Also, a buzzer will produce
sound in order to alert the people inside the mall. If
power supply cuts off, backup fan will take supply
from battery and it will operate thus avoiding
suffocation inside the mall. LED strip will direct the
people in order to avoid chaos.
http://www.ijettjournal.org
Page 320
International Journal of Engineering Trends and Technology (IJETT) – Volume 33 Number 7- March 2016
16. If power supply turns off, all AHU fans will be
turned off. Back up ventilator which is battery
operated will turn ON.
IV. SOFTWARE TOOLS AND SPECIFICATIONS
In this project, two softwares of ABB Company are
used which are easy to understand and good for
simulation
work.
These
softwaressupport
programming languages which provides flexibility to
programmer to program in any desired language. They
are:
1.
Fig.2:Our entire system
Control builder plus
Control builder plus 2.3.0 based on CoDeSys
Automation platform by 3S- Smart Software
solution Gmbh.
Release build 339
Active version profile CBP 2.3.0
2.
CoDeSys (Controlled Development System)
Fig.3:Flow of project
Algorithm for Air Handling Unit using PLC
1. Start
Controlled Development System provides
development environment for PLC which
supports IEC standard and additional online
functions such as setting program variable, inputs
and outputs at certain values and flow control.
2. Entry sensor detects person at entrance.
3. Counter is incremented.
4. PLC gets the signal from the counter.
5. AHU fans turns ON automatically.
6. This is monitored on the SCADA screen.
7. If no. of people inside mall <=3 then 1 AHU fans
will turn ON.
8If no. of people inside mall <=6 and greater than 3
then 2 AHU fans will turn ON.
9. If no. of people inside mall <=10 and greater than 6
then 3 AHU fans will turn ON. So on….
Fig 4: SCADA model screen design
10. Exit sensor will detect the person at the exit.
11. Counter is decremented.
12. PLC gets the signal.
13. AHU fans turns off automatically depending on
the person inside the mall.
14. This is monitored on SCADA screen.
15. If fire gets detected PLC get signal shown on
SCADA screen. Turn off the button to turn off all
AHU fans.
ISSN: 2231-5381
Fig 5:shows number of fans ON and number of people inside
http://www.ijettjournal.org
Page 321
International Journal of Engineering Trends and Technology (IJETT) – Volume 33 Number 7- March 2016
AHU using PLC utilizes energy efficiently as
compared to manually controlled AHU system in
which there is lot of consumption of energy. AHU
system also provides safety in case of fire situation.
VII. FUTURE SCOPE
As in this project energy is being utilized efficiently
so it can be effectively implemented for any realworld application like in buildings, malls, offices. In
case of fire sprinkler can be used to control fire .Using
same PLC with extension module of inputs and
outputs it is possible to implement another application
like automatic street light control in parking which
can be used in mall along with AHU.
Fig 6: shows counter value and time duration foe each fan
V.
PROGRAMABLE LOGIC CONTROLLER
USED
PLC used in this project is PM554 TP ETH which is
powerful compact and cost effective. This PLC uses
Ethernet protocol to download program in to PLC.
Expansion of system is possible because of its
modular design includes wide range of modules.
PM554 TP ETH consists of 8 inputs and 6 outputs and
memory unit of 128 KB flash EEPROM and control
processing unit.
Interfacing of PLC to the real world is done by I/O
unit. I/O parameters are given to PLC as an input from
real world. Inputs from real world are manipulated
based on logic implemented by programmer. All
operations such as logic control, data transfer and
manipulation are done by central processing unit of
PLC. Depending upon the requirement of number of
inputs and outputs, power requirement and type of
application, PLC and CPU range is selected.
Factors like air quality, ratio of CO2 in air,
concentration of oxygen, temperature and humidity
can be easily measured from safety point of view by
using different sensors.
VIII.
[1]
[2]
[3]
[4]
REFERENCES
About control builder plus 2.3.0 and CoDeSys online
help from ABB.
“Programmable Logic Controller, programming methods
and applications” by John R. Hackworth and Frederick
D. Hackworth, Jr.
“Programmable Logic Controller, principles and
applications” by John W. Webb and Ronald A. Reis,
fifth edition
Automated Air Handling Unit system using SCADA
with PLC; International Journal of Ethics in Engineering
and Management Education, Volume !, Issue 4, April
2014.
VI. CONCLUSION
This project concludes that, Air Handling Unit Using
Programmable logic Controller with SCADA
monitoring is effective solution over manually
controlled AHU system .This system would be easily
controlled by SCADA screen. AHU using PLC
provides many advantages over microcontroller such
as availability of large number of inputs and outputs.
This system is more stable than the one which has
been build using microcontroller.PLC also provides
direct inter-operatabilityto industrial devices. Cost
required for its maintenance is less as compared to
microcontroller.Inputs and Outputs of PLC can be
easily extended which is not possible with any
microcontroller. Most of the industrial applications
can bebuilt by using PLC because it is mini CPU as it
has its own O.S., microcontroller and microprocessor.
ISSN: 2231-5381
http://www.ijettjournal.org
Page 322