The History About The Zigbee End Device

Published Date: 02 Nov 2017

Key words: Advanced Risk Machine(ARM),Zigbee, Temperature Sensor.

I. INTRODUCTION

In modern world, embedded systems have become an indispensable part of our life. Use of embedded systems has become so common in our day to day life that every one of us uses them (no matter if we are aware or not). Today 98% of all processors Produced are used in Embedded Systems. Because of their power saving features, ARM CPUs are dominant in the mobile electronics market, where low power consumption is a critical design goal.

SCADA stands for Supervisory Control And Data Acquisition. As the name indicates, it

is not a full control system, but rather focuses on the supervisory level. As such, it is a purely software package that is positioned on top of hardware to which it is interfaced, in general via Programmable Logic Controllers (PLCs), or other commercial hardware modules.

SCADA systems are used not only in industrial processes: e.g. steel making, power generation (conventional and nuclear) and distribution, chemistry, but also in some experimental facilities such as nuclear fusion. The size of such plants range from a few 1000 to several 10 thousands input/output (I/O) channels. However, SCADA systems evolve rapidly and are now penetrating the market of plants with a number of I/O channels of several 100 K: we know of two cases of near to 1 M I/O channels currently under development.

II. METHODOLOGY

In our paper we making use of 3 basic things those are ARM7 that is LPC2148, ZIGBEE module and Temperature sensor (LM35). In the basic Block diagram we have ARM7 Microcontroller, ZIGBEE module and Temperature sensor. We use RS232 to connect the LPC2148 board and ZIGBEE module.

RTU:

Alarm

Driver Unit

Intruder Sensor

Temperature Sensor

ARM7

RS 232

Device 1

Relay Driver

Voltage & Frequency

Zigbee

Device 2

Zigbee module

RS232

S.C:

FIG: 1

LPC2148 MICROCONTROLLER:

As shown the block diagram in Fig 1. We use the latest LPC2148 microcontrollers is based on a 32-bit ARM7TDMI-S CPU with real-time emulation and embedded trace support, that combine microcontrollers with embedded high-speed flash memory ranging from 32 kB to 512 kB. A 128-bit wide memory interface and unique accelerator architecture enable 32-bit code execution at the maximum clock rate. For critical code size applications, the alternative 16-bit Thumb mode reduces code by more than 30 % with minimal performance penalty. Due to their tiny size and low power consumption, LPC2141/42/44/46/48 are ideal for applications where miniaturization is a key requirement, such as access control and point-of-sale.

Serial communications interfaces ranging from a USB 2.0 Full-speed device, multiple UARTs, SPI, SSP to I2C-bus and on-chip SRAM of 8 kB up to 40 kB, make these devices very well suited for communication gateways and protocol converters, soft modems, voice recognition and low end imaging, providing both large buffer size and high processing power. Various 32-bit timers, single or dual 10-bit ADCs, 10-bit DAC, PWM channels and 45 fast GPIO lines with up to nine edge or level sensitive external interrupt pins make these microcontrollers suitable for industrial control and medical systems.

B.ZIGBEE:

Zigbee coordinator (ZC):

The most capable device, the coordinator forms the root of the network tree and might bridge to other networks. There is exactly one Zigbee coordinator in each network since it is the device that started the network originally. It is able to store information about the network, including acting as the Trust Centre & repository for security keys.

Zigbee Router (ZR):

As well as running an application function a router can act as an intermediate router, passing data from other devices.

Zigbee End Device (ZED):

Contains just enough functionality to talk to the parent node (either the coordinator or a router); it cannot relay data from other devices. This relationship allows the node to be asleep a significant amount of the time thereby giving long battery life. A ZED requires the least amount of memory, and therefore can be less expensive to manufacture than a ZR or ZC.

Protocols

The protocols build on recent algorithmic research (Ad-hoc On-demand Distance Vector) to automatically construct a low-speed ad-hoc network of nodes. The current profiles derived from the Zigbee protocols support beacon and non-beacon enabled networks.

In non-beacon-enabled networks (those whose beacon order is 15), an unslotted CSMA/CA channel access mechanism is used. In this type of network, ZigBee Routers typically have their receivers continuously active, requiring a more robust power supply. However, this allows for heterogeneous networks in which some devices receive continuously, while others only transmit when an external stimulus is detected. The typical example of a heterogeneous network is a wireless light switch: the Zigbee node at the lamp may receive constantly, since it is connected to the mains supply, while a battery-powered light switch would remain asleep until the switch is thrown. The switch then wakes up, sends a command to the lamp, receives an acknowledgment, and returns to sleep. In such a network the lamp node will be at least a Zigbee Router, if not the Zigbee Coordinator; the switch node is typically a Zigbee End Device.

In beacon-enabled networks, the special network nodes called Zigbee Routers transmit periodic beacons to confirm their presence to other network nodes. Nodes may sleep between beacons, thus lowering their duty cycle and extending their battery life. Beacon intervals may range from 15.36 milliseconds to 15.36 ms * 214 = 251.65824 seconds at 250 kbit/s, from 24 milliseconds to 24 ms * 214 = 393.216 seconds at 40 kbit/s and from 48 milliseconds to 48 ms * 214 = 786.432 seconds at 20 kbit/s. However, low duty cycle operation with long beacon intervals requires precise timing, which can conflict with the need for low product cost.

In general, the Zigbee protocols minimize the time the radio is on so as to reduce power use. Zigbee devices are required to conform to the IEEE 802.15.4-2003 Low-Rate Wireless Personal Area Network (WPAN) standard. The standard specifies the lower protocol layers—the physical layer (PHY), and the medium access control (MAC) portion of the data link layer (DLL). The basic channel access mode is "carrier sense, multiple access/collision avoidance" (CSMA/CA). That is, the nodes talk in the same way that people converse; they briefly check to see that no one is talking before they start. There are three notable exceptions to the use of CSMA. Beacons are sent on a fixed timing schedule, and do not use CSMA. Message acknowledgments also do not use CSMA. Finally, devices in Beacon Oriented networks that have low latency real-time requirements may also use Guaranteed Time Slots (GTS), which by definition do not use CSMA.

C.Temperature Sensor:

LM35 is a precision IC temperature sensor with its output proportional to the temperature (in oC). The sensor circuitry is sealed and therefore it is not subjected to oxidation and other processes. With LM35, temperature can be measured more accurately than with a thermistor. It also possess low self heating and does not cause more than 0.1 oC temperature rise in still air.   

  The operating temperature range is from -55°C to 150°C. The output voltage varies by 10mV in response to every oC rise/fall in ambient temperature, i.e., its scale factor is 0.01V/ oC.

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Pin No

Function

Name

1

Supply voltage; 5V (+35V to -2V)

Vcc

2

Output voltage (+6V to -1V)

Output

3

Ground (0V)

Ground

D. SCADA:

SCADA is an acronym for Supervisory Control and Data Acquisition. SCADA systems are used to monitor and control a plant or equipment in industries such as telecommunications, water and waste control, energy, oil and gas refining and transportation. These systems encompass the transfer of data between a SCADA central host computer and a number of Remote Terminal Units (RTUs) and/or Programmable Logic Controllers (PLCs), and the central host and the operator terminals. A SCADA system gathers information (such as where a leak on a pipeline has occurred), transfers the information back to a central site, then alerts the home station that a leak has occurred, carrying out necessary analysis and control, such as determining if the leak is critical, and displaying the information in a logical and organized fashion. These systems can be relatively simple, such as one that monitors environmental conditions of a small office building, or very complex, such as a system that monitors all the activity in a nuclear power plant or the activity of a municipal water system. Traditionally, SCADA systems have made use of the Public Switched Network (PSN) for monitoring purposes.

Today many systems are monitored using the infrastructure of the corporate Local Area Network (LAN)/Wide Area Network (WAN). Wireless technologies are now being widely deployed for purposes of monitoring.

SCADA systems have evolved in parallel with the growth and sophistication of modern computing technology. The following sections will provide a description of the following three generations of SCADA systems:

• First Generation – Monolithic

• Second Generation – Distributed

• Third Generation – Networked

III.IMPLEMENTATION

Embedded which already contains many source codes of general purpose hardware device driver for different hardware platforms, they are only needed to be done some simple modifications and then can be used.

In the present method we can find the solution of the paper is to collect the real time parameter values and it control if they exceeds the pre-defined value. Implementation of this paper in a power plant is to monitor and control the real time temperature, voltage and frequency, intruder security with safe and secure operations.

Here device temperature is monitoring by using temperature sensor and the range of voltage is below 210v and above 230v the device must be OFF state. When the voltage is at 220v device must be in ON state. If any unknown person entered into the controller room automatically it indicates the buzzer sound. Zigbee is using for communication between RTU and S.C. Here driver unit is drive the alarm. RS 232 connect the zigbee and controller.

In this paper we can develop the security of the power plant with safe and secure operation. We can control the all the device with remote area.LPC 2148 control the all the devices.

IV. CONCLUSION

In this paper we introduce the scada by using wireless communication. The scada system is used for monitoring and controlling industrial processes from remote areas. It allows an operator to make a set point changes on remote controllers, to open/close, valves/switches, to monitor alarms and to gather instrument information from a local process to a widely distributed process, such as oil/gas fields, pipeline systems, or hydroelectric generating systems. In the context of SCADA, it refers to the response of the control system to changes in the process and makes them similar to real-time control system in the virtual environment.

V. REFERENCES

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D. Maynor and R. Graham (2006). "SCADA Security and Terrorism: We're Not Crying Wolf".

Robert Lemos (26 July 2006). "SCADA system makers pushed toward security". SecurityFocus. Retrieved 9 May 2007.

"Cyber threats, Vulnerabilities and Attacks on SCADA Networks". Rosa Tang, berkeley.edu. Retrieved 1 August 2012.

Slay, J.; M. Miller (November 2007). "Chpt 6: Lessons Learned from the Maroochy Water Breach". Critical infrastructure protection (Online-Aug.ed.). Springer Boston. pp. 73–82. ISBN 978-0-387-75461-1. Retrieved 2 May 2012.

"External SCADA Monitoring". Epiphan Case Studies. Epiphan Systems Inc.. Retrieved 2 May 2012.

"Security for all". InTech. June 2008. Retrieved 2 May 2012.

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KEMA, Inc. (November 2006). Substation Communications: Enabler of Automation / An Assessment of Communications Technologies. UTC – United Telecom Council. pp. 3–21.

Mills, Elinor (21 July 2010). "Details of the first-ever control system malware (FAQ)". CNET. Retrieved 21 July 2010.