Industrial Automation Using ZigBee
In this project, a flexible and low cost automated system based on ZigBee technology is proposed. It uses ZigBee technology to facilitate industry. The system consists of a number of nodes. A node consists of sensors, microcontroller and ZigBee transceiver. They have ability to communicate with main control unit, which is called base station. The sensors here are of different types which will be helpful for industry.
The base station is the central communication point with all the displaying alarming and control units. For this purpose LCD was used. From the main control the user is able to control, any industrial equipment/machine
Automation is the use of information technologies and control systems to decrease the need for labor in the making of goods. In the field of industrialization, automation is a step ahead of mechanization. While mechanization provide human with machinery to support them with the muscular necessities of work, automation significantly decreases the need for human labor and mental necessities as well. Automation plays a gradually more important role in the world economy and in daily experience. The ZigBee wireless standards are gaining favor in industrial environment, where it is preferred due to its low cost and mesh networking topology. Despite its wired networking have a lot of drawbacks. Data cabling requires a great labor cost, in both initial deployment and reconfiguration. In the industry cables are not accepted due to their drawbacks. Cables can represent nuisances and safety hazards. And cabling runs have harsh length limits, as a result networks are unable to address every remote sensor and actuator in such environments. Wireless networking is a good reply to these kinds of issues. Industrial wireless solutions use special techniques to deal with noise and interference.
1.1.1 Industrial Automation
In an industry during certain hazards, it will be very difficult to monitor parameter through wires and analog devices such as transducers. To overcome this problem we use wireless device to monitor the parameters so that we can take certain steps even in worst case. Few years back the use of wireless device was not so common but due to rapid development in technology, now days we transfer data through wireless like Bluetooth, ZigBee, Wi-Fi etc.
This project concerns with the development of a system for remotely monitoring and controlling industrial appliances. It is often desired to check status of nodes and devices remotely. For example, there are many rooms full of industrial machinery, a user who is responsible for monitoring and controlling the system. It is much easier for him to monitor on computer by sitting in control room. Additionally, such a system could be used for emergency situations such as fires and burglaries. The system was developed to monitor temperature, liquid level and voltage level, and to control different appliances automatically.
1.3 Main features
The main features of this project are as following
- The system is composed of emergency /alarm system.
- Can handle upcoming data up to 65,000 nodes, means 65000 different nodes.
- The central controller handles interaction between appliances and user.
- The controller should take necessary actions in case of emergency.
- Display the status of machines on LCD.
- Wireless monitoring and controlling.
1.4 Model of the system
Fgure1.1 Block diagram of the system
Above figure is the basic block diagram of proposed system. Every node is attached to the base station through ZigBee module. The ZigBee which is being used in the base station is interfered with microcontroller. The microcontroller received data from the ZigBee and displayed on the LCD.
1.4.1 Block Diagram of Node
Figure1.2 Block diagram of node
The main components of a sensor node are microcontroller, transceiver, sensors, and power source. These are summarized below
Sensors converts physical data such as light, intensity, flow temperature and speed to electrical signals. We are using following sensors
- Temperature sensor
- Level sensor
- Voltage sensor
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP. ROM is also often included on chip, along with small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications.
A PIC microcontroller chip is used to process data and alerts if any problem is detected by sensors. Microcontroller is programmed using C language. Microcontroller collects data from sensors and processes it and displays information on a LCD.
Sensor nodes often make use of ISM band which gives free radio, spectrum allocation and global availability. In this project ZigBee transceiver was used.
220.127.116.11 Power Source
The sensor node consumes power for sensing, communicating and data processing. More energy is required for data communication than any other process. The energy cost of transmitting 1 Kb a distance of 100 meters (330 ft) is approximately the same as that used for the execution of 3 million instructions by a 100 million instructions per second/W processor. Power is stored either in batteries or capacitors. Batteries, both rechargeable and non-rechargeable, are the main source of power supply for sensor nodes
1.4.2 Block Diagram OF Base station
Figure 1.3 Block Diagram of base station
The main components are given below
Sensor nodes often make use of ISM band which gives free radio, spectrum allocation and global availability. We are using ZigBee transceiver.
18.104.22.168 Power Source
ZigBee transceiver needs 3v to operate and microcontroller need 5v. Power source provides essential power to all node components.
22.214.171.124 Liquid Crystal Display
A LCD is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals (LCs). LCs does not emit light directly. They are used in a wide range of applications. LCD is used to show status of nodes.
1.5 Research and Initial Approaches
Wireless protocol and sensors were most critical part of project. It was required to have sound knowledge of their working.
1.6 Wireless Networks
The wireless networks avoids the mess of wires. Modern technologies are leading towards systems which majorly have mobility features; a wireless network has huge significance over a wired network.
One of the objectives of the wireless network protocols is the reduction of power cabling by allowing the autonomy of certain nodes through battery power and even solar power. This brings the advantages of easier and cheaper network installation, more flexible setting of nodes and relocation of nodes. Low-capacity batteries are often used and their use is optimized by restricting the time for which energy is required. However, since some node types (such as coordinator) must be switched on all the time.
Wireless networking field has massively developed over the last few years. Many protocols have been designed. They have some pros and cons.
Some of them are mentioned below.
- Radio Frequency (RF)
- It was introduced 10 years back for short-range communication.
- It has a frequency of 2.4 GHz.
- Its range is 10 meters with 2.5mW power consumption.
- Majorly used in Phones, personal computers (PC), Personal Digital Assistance (PDA).
- Supports star topology communication.
- It works on either 413 MHz or 315 MHz frequency.
- Module doesn’t contain any protocol.
- It broadcasts the signal without security.
- Supports only star topology.
- Range can cover upto 100 meters.
- ZigBee is a protocol that based on OSI model
- ZigBee supports three topologies
- Star, Tree/Cluster and mesh topology.
- Operates with very-low power consumption
- ZigBee has multi-hop communication capability
- Frequencies: 2.400–2.484 GHz, 902-928 MHz and 868.0–868.6 MHz
1.6.2 Radio Frequency (RF)
Table 1.1 Comparison of different wireless technologies.
1.6.4 Why ZigBee?
ZigBee standard is low power, small size, low cost and low data rate wireless networking protocol used for the automation and remote control application. In industrial automation, there is no need of high data rate because there is small amount of data to send. So ZigBee was chosen.
1.7 Hardware components
- ZigBee Kit(JN5139)
- PIC microcontroller(16F877A)
- Temperature sensor
- Voltage sensor
- Level sensor
- Jennic code blocks
- Jennic flash programmer
1.8 Software components
Three boards were required to start the work. Two boards were selected to work as coordinator and router. One was selected as end device. A coordinator is necessary for initiating the network. A network can have only one coordinator while it can have more than one routers and end devices. To start a coordinator, push its SW2 button before pushing power button. Later SW1 button is pushed to initiate the network. Led at SW1 and SW2 gives indication that network has been made. Now router and end device are initiated. To turn on router, simply push power button and press SW1 and SW2. Router will start searching for coordinator, at establishment of connection led on SW1 and SW2 will blink once. When end device is turned on it will try to connect with coordinator and led at coordinator will blink to indicate the successful establishment of connection.
The level sensor was used to check the maximum and the minimum level of the tank. When the level cross the maximum level, the alarm would generates at the coordinator side.
To show the functions of the level sensor, two switches were designed, one for the minimum level and the second for the maximum level. Upon pressing the maximum level switch an interrupt send to the 33 RB0 and 34 RB1 micro-controller pins respectively and in result a wireless signal transmit to the coordinator by ZigBee. The alarm would generate at the coordinator side when the liquid is at maximum level.
The voltage level sensor was to detect variation in the voltage. After setting the voltage limit, if the voltages drop or increased from that limit the alarm would generate at the coordinator side.
To show the functions of the voltage level sensor a variable resistor has used which operates at 0V-5V. After setting an acceptable level of voltage for the particular machine if the voltage level increased or decreased from that level interrupt send to the 3rd RA1/AN1 micro-controller pin and in result a wireless signal transmit to the coordinator by ZigBee. The alarm would generate at the coordinator side if the voltages increased or decreased.
The performance of the ZigBee kits shows that it’s a very useful technology and a remarkable breakthrough in the wireless network. The ZigBee is still new in the market and has not widely deployed commercially. There are lot of choices for selecting the hardware as many of the vendors present in the market including Texas Instruments, Free scale semiconductors, ATMEL and Jennic. The module which was purchased is 32-Bit RISC based processor and 96 kB of RAM and 192 kB of ROM.
Jennic modules (ZigBee controller manufactures) were chosen, as it was very easy to understand them. Also the help available from Jennic was very extensive and provided in detailed. The project focused to get the data from the sensors and transmits the data wirelessly to the base station and displayed onto the LCD connected to one of the ZigBee module. An interesting future study might involve testing the different strategies of routing techniques. The most interesting thing that was noticed during the project is that the 802.15.4 is indeed a very low power consuming standard.