Abstract: In modern generation the automation has become
a basic need for the industries. This paper proposed a wireless control and
observing system for an induction motor based on Zigbee communication
arrangement for safe and economic data communication in industrial fields, where
the wired communication is highly precious or impossible due to physical circumstances.
This paper has two parts that is transmitter and receiver techniques. In
receiver section microcontroller is used for controlling operation of induction
motor. A microcontroller based system is used for assembling and storing data
and accordingly generating control signal to stop or start the induction motor,
wireless through computer interface developed with Zigbee.
No other motors are popular such
as Single phase and three phase induction motor because of their wide
applications in industries. Hence it becomes necessary to protect them against
faults so as to ensure uninterrupted operation and functioning. For other types
of motor there are various parameter controlling and monitoring systems, but in
case of induction motor the controlling and monitoring systems are
insignificantly used due to high cost of installation and physical limitations.
So as to reduce the limitations in monitoring and controlling, Zigbee based
system is used which makes it cheap and simple than other.
What is zigbee? Zigbee is a
wireless communication device like Bluetooth and Wireless Local Area Network (WLAN).
Basic difference between Zigbee and other communication protocol is that all
zigbee devices relay each other’s traffic, by passing the wired network perfectly.
While Bluetooth devices connect to another wireless that acts as a focal point
and WLAN devices connect directly to an access point, which is wired to the network using Ethernet. The Institute Of
Electrical and Electronics Engineers (IEEE) developed standards and helped the
production of Zigbee protocol and devices that support this protocol. The
disadvantage of using traditional systems is that it increases the cost whereas
digital systems reduce the cost of system. The basic structure of Zigbee based
parameter monitoring and controlling system consists of microcontroller and
Zigbee devices, one set of microcontroller and Zigbee device are near computer and
acts as transmitter for the other microcontroller and Zigbee device which is
near the induction motor where the parameters are displayed on computer using
software application. In addition to Zigbee device various other sensors are
used for measuring different parameters. Wireless sensors network (WSN) system
are autonomous and operate unattended also adaptive to the environment.
ABOUT ZIGBEE TECHNOLOGY
WIRELESS SENSOR NETWORK
Wireless sensor network systems
are self- governing and operate disregarded also adaptive to the environment.
The wireless system for monitoring purpose will not only reduce the overall
monitoring system cost, but always provide flexibility in the system in terms
of distance or location. So these systems are widely used in military,
hospitals, home and other commercial areas. According to this feature the Zigbee
becomes the new standard planned for low cost devices in automation, computer constituent
and home controls. Zigbee standard performs
well at industrial environments. The fundamental design and implementation of
WSN promoting a high power transmission Zigbee based technology. The developed area
is cost-effective and allows easily in WSN systems and as well as the effect on
reducing energy consumption.
ZIGBEE NETWORK STRUCTURES
There are three network topologies
which are used. They are star Network, Cluster-tree Network and Mesh Network.
Different network topology built up by zigbee devices like star topology cluster
tree topology and mesh network. For all network topology, there can be only one
coordinator in each network. In cartography there is a coordinator which is
responsible for all over the network. All other devices are back-end devices
and directly communicate with the coordinator. This topology is suitable for
networks with a centralized device and for time critical applications. Next is
a cluster tree network where coordinators are still dependable for the network
initiating and maintenance. However, routers can be used to extend the network.
Routers control data flow by using hierarchical routing strategies in the network.
They also may imply become enabled network that is defined in IEEE for
periodical data transmission. In mesh network coordinators seen as responsible
for the network initiating and maintenance. Routers can be used to extend the
network. A mesh network allows full peer to peer communication. A mesh relies
on this way self-healing technology so that if a node fails another route is
used for the data delivery.
MONITORING AND CONTROLLING SCHEMES
This section gives the overview
of the monitoring and controlling scheme of induction motor. A general block
diagram of the proposed schemes is given in fig.1.A general block diagram of
monitoring and controlling schemes.
The whole system is divided into two parts –transmitter
and receiver. In the transmitter part network of sensor and transducers are used
to monitor the risky parameters such as voltage, current, temperature of stator
winding and speed of the induction motor present at the plant location. The
monitoring data is simultaneously fed to the microcontroller. This data is
transmitted efficiently and smoothly to receiver and through wireless zigbee
communication protocol. The microcontroller at the transmitter end is so
programmed that if the monitoring parameters of induction motor come out of the
desired or safety limits, a signal will be generated by the microcontroller
which will energize the relay circuit and the contractor cuts the mains supply
to the induction motors.
The data receives at the receiver
end is transferred to the computer system through MAX232 interface. Thus a
continuous monitoring of the parameters of the induction motor can be done from
a remote location far away from the actual working location. If the user any
time wants to stop and start the induction motor, a signal will be given by the
computer system present at the receiver end, which is communicated at the
transmitter end through zigbee protocol. Intern the micro controller unit
presents at the plant location generates a signal which energizes and
de-energizes the relay circuitry to start and stop the induction motor
respectively. Thus the system not only monitors the operation of the induction motor
but also protects it from the severe faults that commonly occur.
4. RESULT AND DISCUSSION
This paper concerned on the experimental studies on simple
motor load for speed control using wireless technology through the
microcontroller. The experiment is conducted by placing motor at distance of
about 80-100 meters and tested the motor to obtain various speeds by pressing
the different keys in the keypad. Here tON is maintained constant and tOFF is varied accordingly. The speed of the
motor for various keys selected in the keypad.
Thus we can vary the speed of induction motor by
pressing respective keys.
No. of Keys pressed
Status/speed in rpm
Table: speed control
for various keys selected in the keypad
With the help of the study, a
parameter monitoring system for induction motor based on Zigbee protocol is
achieved and tested successfully. The system developed is capable to perform
such operation as running the motor through RF, stopping it, measuring, monitoring
and controlling the most parameter of the motor like phase current, phase
voltage, wiring temperature, speed. All of these values can be transferred to
the host computer, display on the interface represents graphically; monitoring
and controlling the basic parameters of the induction motor where examined and
achieved in various ways. A new Zigbee technology is a new wireless protocol is
used for the communication. These protocol is widely used various areas for it
better reliability, low power consuming profile, excellent capability, high
flexibility and low cost so it’s significant to embed the Zigbee protocol into
the WSN system that widely applied now in every areas. The system achieved can
be used for industrial application. The whole system may be very useful to
colleges and research institutes that have occasional, technical and industrial