A LOW-COST DISTRIBUTED CLIMATE CONTROL SYSTEM (DCCS)
Abhimanyu Sanghi (02/EC/05)
Ankur Verma (15/EC/05)
Ashish Bhandari (20/EC/05)
Kshitij Gupta (41/EC/05)
Mentors
Astt. Prof. S.P. Singh
Prof. Subrat Kar (I.I.T. Delhi)
A QUICK SUMMARY…
Introduction
Work Completed
Future Work
Conclusion
This presentation discusses Distributed Climate Control System (DCCS).
Introduction
Climate encompasses Temperature Humidity Atmospheric Gases e.g. CO2, CO …
Ideal climatic conditions and parameter values vary. Climate control essential for
Manufacturing, processing, packaging, transport or storage of various sensitive goods
To prevent damage, deterioration or contamination of sensitive goods.
Motivation behind DCCS
We propose to devise DCCS to control climate parameters!
WHAT IS DISTRIBUTED CLIMATE CONTROL SYSTEM (DCCS) ?
Slave Nodes measure
parameters
Master logs and responds to changes
Sensor Data/Feedback Decision
Block Diagram of Proposed System
Work Completed
• Cost of each node ~ Rs. 600• Selection of suitable microcontroller
ARM / MSP430 / AVR / PIC
• Interfacing sensors with microcontroller• Interfacing with CAN, fan and external memory
Requires SPI and TWI
• Choice of communication networks CAN / RF / RS485 / RS232
SYSTEM SPECIFICATIONS
CHOICE OF COMPONENTS
1. eZ430-RF2500 Development board.
2. MSP430F169.
3. AT90CAN32.
4. ATmega16.
ATmega16 is selected which meets system requirements
SELECTION OF MICROCONTROLLER
CHOICE OF COMPONENTS (CONTD.)
1. RS232.2. RS485.3. Zigbee.4. CAN.
CAN Network is selected for our system.
SELECTION OF COMMUNICATION NETWORK
1. CAN Controller MCP2515, Microchip Technology
2. CAN Transceiver MCP2551, Microchip Technology
3. Temperature Sensor LM35
4. Other Components : IC-MAX232, General Purpose Board, Resistors, Capacitors, Switches, LEDs etc.
Total Expenditure per node ~ Rs. 675
SELECTION OF OTHER COMPONENTS:
CHOICE OF COMPONENTS (CONTD.)
Cost Analysis
Block Diagram of DCCS
SPICANSPITWI
Working of DCCS
SPICANSPITWI
FAN
Working of DCCS
Ext. Peripherals
Temperature Sensor
External Memory
LCD
DC Motor
External Peripherals
Temperature sensor LM35
ADCMicrocontroller
Temperature Sensor(LM 35)
Block Diagram
LM35
External Peripherals
EEPROMExternal Peripherals
Mask lower 4-bitsSend to the LCD portSend enable signalMask higher 4-bitsSend to LCD portSend enable signal
Send data/command Using 4-bit Mode
LCD
Block Diagram
External Peripherals
DC MOTORMOTOR DRIVER
Microcontroller
DC MOTOR
Block Diagram
Motor
External Peripherals
MOTOR
SLAVEµC
MASTER µC
MEMORY (EEPROM)
LCD
Temperature sensor LM35
MASTER NODESLAVE NODE
Block Diagram highlighting External Peripherals
External Peripherals
CAN
CAN -- Controller Area Network
Bus Standard Allows microcontrollers and devices to
communicate with each other without a host computer
Message based protocol Event triggered Bit rates up to 1 Mbps
Introduction to CAN
CAN & OSI Model
Communication between two nodes over CAN
Features of CAN Communication
Data transmitted through dominant bits (0) and recessive bits (1)
All devices read bus value while transmitting
Collision avoidance via bitwise arbitration
Error detection via bit stuffing
Requirements of a CAN Node
• Host processor ATmega16 • CAN Controller MCP2515• CAN Transceiver
MCP2551
Interfacing at Master Node
Interfacing at Slave Nodes
Code Design
Device Driver for CAN ControllerFunctions to read from and write to the controller
Thus, SPI has:
4 interface pinsMOSI, MISO,SCK, SS or CS
3 registersSPDR data, SPSR status , SPSC control
Writing SPDR -> Initiates Data Transfer
All data movement is coordinated by SCK.
SPI Data Register (SPDR)
Thus, SPI has:
4 interface pinsMOSI, MISO,SCK, SS or CS
3 registersSPCR control , SPSR status , SPDR data
Interrupt flagSet when serial transfer is complete
SPI Status Register (SPSR)
Thus, SPI has:
4 interface pinsMOSI, MISO,SCK, SS or CS
3 registersSPCR control , SPSR status , SPDR data
Interrupt flagif set, interrupt occurs!
SPI Control Register (SPCR)
SPI enableif set, SPI interface enabled
Clock Polarity and RateIdle mode SCK and Rate
Configuration of CAN Controller
Resets the CAN Controller
How to transmit data bytes
DCCS AlgorithmMaster Node
CAN Bus
Slave Node 2
CAN Bus
Slave Node 1
CA
N
Bu
sTemp. Senso
rFAN
Temp. Senso
rFAN
Step 1: INITIALIZATION
Receive Buffer Filters of Slave Nodes are set such that they receive onlycorresponding Master Node messages.
Reset
Filter Set
Filter Set
DCCS AlgorithmMaster Node
CAN Bus
Slave Node 2
CAN Bus
Slave Node 1
CA
N
Bu
sTemp. Senso
rFAN
Temp. Senso
rFAN
Step 2: Wait…
Slave Nodes 1 and 2 waits for incoming trigger messages from MasterNode.
Ready
WaitWait
DCCS AlgorithmMaster Node
CAN Bus
Slave Node 2
CAN Bus
Slave Node 1
CA
N
Bu
sTemp. Senso
rFAN
Temp. Senso
rFAN
Step 3: Node 1 Triggers
Master Node sends message intended for Slave Node 1 first and waits forits response.
Sending
Message
Msg. Rxd.
WaitTR
IGGER
DCCS AlgorithmMaster Node
CAN Bus
Slave Node 2
CAN Bus
Slave Node 1
CA
N
Bu
sTemp. Senso
rFAN
Temp. Senso
rFAN
Step 4: Node 1 Sends Data
Slave Node 1 replies with data and again waits.
Master Node logs data in EEPROM
Node 1Data
Logged
Sending
Sensor Data
WaitSen
sor
Dat
a
DCCS AlgorithmMaster Node
CAN Bus
Slave Node 2
CAN Bus
Slave Node 1
CA
N
Bu
sTemp. Senso
rFAN
Temp. Senso
rFAN
Step 5: Node 2 Triggers
Master Node sends message intended for Slave Node 2 and waits forits response.
Sending
Message
Wait
Msg. Rxd.
TRIG
GER
DCCS AlgorithmMaster Node
CAN Bus
Slave Node 2
CAN Bus
Slave Node 1
CA
N
Bu
sTemp. Senso
rFAN
Temp. Senso
rFAN
Step 6: Node 2 Sends data
Slave Node 1 replies with data and again waits.
Master Node logs data in EEPROM
Node 2Data
Logged
WaitWait
Sensor
Data
DCCS AlgorithmMaster Node
CAN Bus
Slave Node 2
CAN Bus
Slave Node 1
CA
N
Bu
sTemp. Senso
rFAN
Temp. Senso
rFAN
Step 7: Process Repeats
Master node send trigger signal to Node 1 and process repeats…
Sending
Message
Msg. Rxd.
WaitTR
IGGER
Testing : Loopback
Integration
Basic CAN Communication
Interfacing Peripherals
Selection of Components
DCCS – Working Demo
Future Work
Future Work Characterization of temperature sensor Interfacing slave nodes with other climate
sensors and controllers Effect of increase in number of nodes on
efficiency of system Effect of increase in length of CAN Bus
Conclusions
Conclusions
• Average cost of slave node is ~ Rs. 700• Prototype includes one master node and two
slave nodes• External Peripherals (EEPROM, LCD, Sensors and
Motor) are interfaced• System Development and Extensive Debugging
was done
We propose the use of this system as either a stand-alone system in the industry or workplace
or as an integrated device with climate modifying appliances such as an air conditioner
or a heater
Thank you.