K.Venkata Ramana, U.Phaneendra Kumar Chaturvedula / International Journal of
Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.965-968
Wireless Power Meter Using Data Acquisition
K.Venkata Ramana #1 U.Phaneendra Kumar Chaturvedula*2
#
M.Tech, Embedded Systems, Nova College of engineering and technology.
M.Tech, Embedded Systems, Nova College of engineering and technology.
*
Abstract:
Our aim of the project is to provide a
wireless meter reading device for implementing
the data acquisition or for observing the power
theft occurring in the present power distribution
system. The project also can be used as the
monitoring section of the power parameters in
case of fault occurrences in parameters like
voltage, current and frequency. The transmitter
section contains a VT and CT for measuring load
voltage, current and frequency. The parameters
are converted into digital data using ADC 0809
and then forwarded to the micro controller. The
micro controller transmits the data using 433MHz
zigbee transmitter and the data is received using
433MHz receiver and then provided to amplifier
for current amplification and the provided to
micro controller for displaying and comparison of
values for permissible limits.
Keywords: Data Acquisition, 433mhz, Zigbee
Transmitter, micro controller, MAX23C
I INTRODUCTION
With the electric industry undergoing
change, increased attention is being focused on power
supply reliability and power quality. Power providers
and users alike are concerned about reliable power,
whether the focus is on interruptions and disturbances
or extended outages. One of the most critical elements
in ensuring reliability is monitoring power system
performance. Monitoring can provide information
about power flow and demand and help identify the
cause of power system disturbances. It can even help
identify problem conditions on a power system before
they cause interruptions or disturbances.
The implementation of this project is to
monitor the power consumed by a model organization
such a household consumers from a centrally located
point. Monitoring the power means calculating the
power consumed exactly by the user at a given time.
The power consumed by the user is measured and
communicated to the controlling substation whenever
needed by the person at the substation. The
communication can be of two types
1. Wired communication like using the existing
transmission lines and sending the data by modulating
with high frequency carrier signal or using the existing
telephone lines.
2. Wireless communication based on the available
technologies like IR communication, Bluetooth
technology or GSM technology. Among these two
communications, the one used in our project is wired
communication which suits best for long distance
communication.
II SYSTEM ARCHITECTURE
The block diagram consists of Load, current
transformer,
voltage
transformer,
89C52
microcontroller, ADC 0809, and a differential relay.
The household load to be supplied is connected in
series to the AC supply mains through a switch which
is operated by the action of a relay. Current
transformer is used to measure the current required
for the user and the voltage transformer is used to
measure the voltage of operation for the user. The
measured values are given to the ADC to convert the
analog values to the digital values. These values are
stored in microcontroller registers and the
information is transmitted to the pc when ever there is
a request for the data from the remote controlling
station. Oscillator is provided for the ADC and
microcontroller for the clock signal and the reference
voltage is given for the each of the IC used.
Fig 1:Transmitter block diagram
965 | P a g e
K.Venkata Ramana, U.Phaneendra Kumar Chaturvedula / International Journal of
Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.965-968
This supplier side is the basic for the operation of the
project; the entire consumer side is controlled in
accordance with the program written on this supplier
side. The supplier side (substation) is located
remotely at some distance away from the user and the
signal is sent to the consumer side for data or to
control the supply of power to the user. The request
for information and the power data is received from
the user side via RS232. Microcontroller is interfaced
to the personal computer serial port through
MAX23C to drive between RS232 and TTL levels.
Application Programmable (IAP), allowing the Flash
program memory to be reconfigured even while the
application is running.
Fig 3 AT89C52 MICRO CONTROLLER
Fig 2 :Receiver block diagram
B. FUNCTIONAL DESCRIPTION
Power-On reset code execution
Following reset, the AT89C52 will either
enter the Soft ICE mode (if previously enabled via
ISP command) or attempt to auto baud to the ISP
boot loader. If this auto baud is not successful within
about 400 ms, the device will begin execution of the
user code.
A. Micro Controller (AT89C52)
The AT89C52 is 80C51 microcontrollers
with 128kB Flash and 1024 bytes of data RAM.A key
feature of the AT89C52 is its X2 mode option. The
design engineer can choose to run the application
with the conventional 80C51 clock rate (12 clocks per
machine cycle) or select the X2 mode (6 clocks per
machine cycle) to achieve twice the throughput at the
same clock frequency. Another way to benefit from
this feature is to keep the same performance by
reducing the clock frequency by half, thus
dramatically reducing the EMI.
The Flash program memory supports both
parallel programming and in serial In-System
Programming (ISP). Parallel programming mode
offers gang-programming at high speed, reducing
programming costs and time to market. ISP allows a
device to be reprogrammed in the end product under
software control. The capability to field/update the
application firmware makes a wide range of
applications possible. The AT89C52 is also In-
C. IN-SYSTEM PROGRAMMING (ISP)
In-System Programming is performed
without removing the microcontroller from the
system. The In-System Programming facility consists
of a series of internal hardware resources coupled
with internal firmware to facilitate remote
programming of the AT89C52 through the serial port.
This firmware is provided by Atmel and embedded
within each AT89C52 device. The Atmel In-System
Programming
facility has
made
in-circuit
programming in an embedded application possible
with a minimum of additional expense in components
and circuit board area. The ISP function uses five
pins (VDD, VSS, TxD, RxD, and RST). Only a small
connector needs to be available to interface your
application to an external circuit in order to use this
feature.
Input/output (I/O) ports 32 of the pins are
arranged as four 8-bit I/O ports P0–P3. Twenty-four
of these pins are dual purpose with each capable of
operating as a control line or part of the data/address
966 | P a g e
K.Venkata Ramana, U.Phaneendra Kumar Chaturvedula / International Journal of
Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.965-968
5
1
2
6
1
VIN
VOUT
GND
1N4001
AC230V
+ C1
4
8
1
3
2
+ C2
2200uF/25V
7805
TRANSFORMER
470uF/16V
2
1N4001
103 SIP
1
VCC
2
3
4
5
6
7
8
9
VCC+5v
8.2K
2
1
2
3
4
5
6
7
8
VCC
+
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
10/16
13
12
XTAL1
8
19
6
10
9
18
3
4
5
8.2K
LCD
VCC
12 V
AT89C51/FP
9
8
7
6
5
4
3
2
1
Vcc
data
Gnd
Ant
8.2K
1
2 EN
14A
13A
12A
11A
10A
9A
8A
7A
6A
5A
4A
3A
2A
1A
RST
P3.0/RXD
31
P3.1/TXD
EA/VPP 30
P3.2/INT0 ALE/PROG 29
P3.3/INT1
PSEN
P3.4/T0
28
P3.5/T1
P2.7/A15 27
P3.6/WR
P2.6/A14 26
P3.7/RD
P2.5/A13 25
P2.4/A12 24
P2.3/A11 23
P2.2/A10 22
P2.1/A9 21
20
GND
P2.0/A8
433MHz Rxd
VCC
39
38
37
36
35
34
33
32
P0.1/AD1
P0.0/AD0
P0.2/AD2
P0.3/AD3
P0.4/AD4
P0.5/AD5
P0.6/AD6
P0.7/AD7
9
10
11
12
13
14
15
16
17
ANTENNA
40
VCC
XTAL2
1
illegal connection switch
1
103 SIP
+
Buz
-
11
74hc125
33pf
33pf
11.0592
Q?
BC547
D?
4007
Fig 4 Transmitter Schematic diagram
VCC
T1
5
1
6
2
1
+ C1
4
8
1
3
VOUT
1N4001
AC230V
2
4007
+ C2
2200uF/25V
7805
TRANSFORMER
1
VIN
GN D
1
470uF/16V
2
1N4001
5
103 SIP
4007
103
VCC
+
6
10/60
4
8
VCC+5v
1
4007
10/60
8
7
10
1
2
3
4
5
6
7
8
VCC
ALE
START
A0
A1
A2
XT AL1
U?
6
2
LM555
18
4
VCC
3
AT89C52/FP
C?
33pf Y?
11.0592
5
1
39
38
37
36
35
34
33
32
C? +
10/16
1RN?
103 SIP
C?
33pf
R?
8.2K
C?
104p
VCC
433MHz Txd ANTENNA
4
Ant
Vc c
D at a
Gnd
C?
104p
8
ADC0809
R? 7
4.7K
40
RST
P3.0/RXD
31
P3.1/TXD
EA/VPP 30
P3.2/INT0 ALE/PROG 29
P3.3/INT1
PSEN
P3.4/T0
28
P3.5/T1
P2.7/A15 27
P3.6/WR P2.6/A14 26
P3.7/RD P2.5/A13 25
P2.4/A12 24
P2.3/A11 23
P2.2/A10 22
P2.1/A9 21
20
GND
P2.0/A8
22
6
25
24
23
16
13 REFGND
R?
10K
VCC
P0.1/AD1
P0.0/AD0
P0.2/AD2
P0.3/AD3
P0.4/AD4
P0.5/AD5
P0.6/AD6
P0.7/AD7
9
10
11
12
13
14
15
16
17
EOC
CLK
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
Fig 5 Receiver Schematic diagram
The above figure shows the circuit diagram for the
consumer side. A relay operated switch is connected
in series with the load. The switch is used to switch
on and off the power. By the relay is initially in on
state and whenever the voltage across its terminals
changes the relay senses the voltage and trips which
in turns closes the switch. The relay is connected to
the port of the microcontroller through a transistor
967 | P a g e
2
9
11
12
17
14
15
8
18
19
20
21
1
4
VOLTAGE TRANSFORMER
D0
D1
D2
D3
D4
D5
D6
D7
X
+
6
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
9
8
7
6
5
4
3
2
103
16
2
3
4
5
6
7
8
9
14A
13A
12A
11A
10A
9A
8A
7A
6A
5A
4A
3A
2A
1A
U?
XT AL2
5
104pf
19
26
27
28
1
2
3
4
5
4007
1
OE
U?
VC C
R EF +
4007
LCD
CURRENT TRANSFORMER
1
2
3
III SCHEMATIC DIAGRAM
VCC
T1
1
1
2
3
4
bus in addition to the I/O functions. Details are as
follows:
Port 0: This is a dual-purpose port
occupying pins 32 to 39 of the device. The port is an
open-drain bidirectional I/O port with Schmitt trigger
inputs. Pins that have 1s written to them float and can
be used as high-impedance inputs. The port may be
used with external memory to provide a multiplexed
address and data bus. In this application internal pullups are used when emitting 1s. The port also outputs
the code bytes during EPROM programming.
External pull-ups are necessary during program
verification.
Port 1:
This is a dedicated I/O port
occupying pins 1 to 8 of the device. The pins are
connected via internal pull-ups and Schmitt trigger
input. Pins that have 1s written to them are pulled
high by the internal pull-ups and can be used as
inputs; as inputs, pins that are externally pulled low
will source current via the internal pull-ups. The port
also receives the low-order address byte during
program memory verification. Pins P1.0 and P1.1
could also function as external inputs for the third
timer/counter i.e.:
(P1.0) T2 Timer/counter 2 external count
input/clockout
(P1.1)
T2EX
Timer/counter
2
reload/capture/direction control
Port 2:
This is a dual-purpose port
occupying pins 21 to 28 of the device. The
specification is similar to that of port 1. The port may
be used to provide the high-order byte of the address
bus for external program memory or external data
memory that uses 16-bit addresses. When accessing
external data memory that uses 8-bit addresses, the
port emits the contents of the P2 register. Some port 2
pins receive the high-order address bits during
EPROM programming.
Port 3:
This is a dual-purpose port
occupying pins 10 to 17 of the device. The
specification is similar to that of port 1. These pins, in
addition to the I/O role, serve the special features of
the 80C51 family B.
LCD
K.Venkata Ramana, U.Phaneendra Kumar Chaturvedula / International Journal of
Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.965-968
and zener diode to drive the relay. The current
IV KIT DIAGRAM
transformer primary is connected to the load in series
to the mains and the secondary is connected across
the variable resistance to change the measured value
to the close actual value. The potential transformer
primary is connected in parallel to the load to
measure the applied voltage and the secondary is
connected to the variable resistance to adjust the
measured value to the close accurate value. The
outputs of this are given to the ADC analog input
pins. A 555 timer is connected in astable
multivibrator mode and is given as clock signal to the
ADC. The digital outputs are given as inputs to the
microcontroller port.
The control pins of the ADC are given from
the microcontroller port to select the input to be
received. The voltage and current measured are
received in accordance to the inputs given to the
status pins A, B, C by the controller. The ADC starts
the conversion at the end of the pulse Start and sends
data at the end of the pulse EOC these are also
connected to the port of the microcontroller. The
microcontroller is provided with a quartz crystal to
provide the clock signal, the clock frequency is
changed by the capacitors connected to the crystal the
operating frequency in this circuit is 11.0592MHz.
A series combination of the resistor and
capacitor is taken and the capacitor voltage is given
as the reset logic to the 9th pin of the microcontroller.
The 10th pin of the microcontroller is the RXD pin is
connected to the receiver data pin of RS232. The data
from the RXD is stored internally for further
processing. The 11th pin of the microcontroller is the
TXD pin is connected to the RS232 which transmits
the data
from
the microcontroller. The
microcontroller baud rate is set in accordance to the
frequency of the 555 timer to ensure consistency of
data. Thus data is transmitted from the
microcontroller at a preset frequency and the request
for data is received by the microcontroller connected
to the port and the further processing is done as per
the code written to calculate the power by taking the
correction factors in to consideration.
The computer is programmed so as to send
requests for data and receive data via the serial port.
The work at TTL voltage levels and the computer
works at RS232C voltage levels. So to bridge this
voltage variation MAX 232C is used which is driver
cum receiver.
The driver is connected to the IR transmitter
and the receiver is connected to the IR receiver. The
data from data pin of IR receiver is given to the
computer and displayed on the screen. IR transmitter
is connected to the computer and the program is
written to send the data via the serial port to the IR
transmitter to send data at a given baud rate. The
oscillator is connected to the transmitter to match the
transmission with the baud rate. The oscillator used is
555 timer using astable multivibrator.
V CONCLUSION
The ability to remotely monitor
and/or control power at the rack level can provide a
huge return on investment by providing savings in
both man hours and downtime. Remote monitoring
capabilities eliminate the need for manual power
audits as well as provide immediate alerts to potential
problems. Remote control allows for quick response
and recovery of stalled hardware either down the hall
or across the country. This ability can save not only
travel costs but minimize costly downtime.
REFERENCES
[1]
Nordic VLSI.Data sheets
Multiband Transceiver.2005
for
nRF905
[2]
[3]
http://batescomponents.com/catalog/parts/78
LE54-2 4.html
Popa, M.Popa, A.S., Cretu, V., Micea, M.,
“Monitoring Serial Communications in
Microcontroller Based Embedded Systems
Computer Engineering and Systems”, The
2006 International Conference on，Nov.
2006 Page(s):56
- 61Computational
Intelligence in Scheduling (SCIS 07), IEEE
Press,
Dec.
2007,
pp.
57-64,
doi:10.1109/SCIS.2007.357670.
968 | P a g e