6367(Print), ISSN (Online) Volume (IJCET) 3, Issue 2, July- September (2012), IAEME

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1 INTERNATIONAL International Journal JOURNAL of Computer OF Engineering COMPUTER and Technology ENGINEERING (IJCET), & ISSN TECHNOLOGY (Print), ISSN (Online) Volume (IJCET) 3, Issue 2, July- September (2012), IAEME ISSN (Print) ISSN (Online) Volume 3, Issue 2, July- September (2012), pp IAEME: Journal Impact Factor (2011): (Calculated by GISI) IJCET I A E M E INTELLIGENT SECURITY SYSTEM FOR LPG PLANT USING GSM PROTOCOL Mr. P.A. Patil 1, Prof. S. A. Naveed 2, Prof. M.A. Parjane 3 1 Student, Jawaharlal Nehru Engineering College, Aurangabad, M.S., India patil_pankajashok@yahoo.co.in 2 Professor, Jawaharlal Nehru Engineering College, Aurangabad, M.S., India. sa_naveed01@rediffmail.com 3 Assistant Professor, S.N.D. College of Engineering & Research Centre, Yeola, M.S., India mparjane@gmail.com ABSTRACT Gas leak detection methods became a concern after the effects of harmful gases on human health were discovered. One of the easiest ways to detect gas leak is using smell. Natural gas does not have odour, gas companies add mercaptan to the gas so that it can be easily detected. Before modern electronic sensors, early detection methods relied on less precise detectors. Presently available gas leakage alarms do not provide any PC interface. They also do not provide any automatic control on gas leakage. If there is nobody at home, then chances of alarm being heard by outsiders become less, when there is a gas leakage. The objective of system designed is to provide automatic control and PC interface to the sensor. Each sensor will be placed at an appropriate place in LPG plant where there is chance of leakage. The Master Controller interfaced with PC, located in cabin of watchman will continuously monitor status of each sensor. If there is no gas leakage, then OK status will be displayed on PC. If there is gas leakage then Emergency status will be displayed on PC and also control action will be taken by activating solenoid valve to shut off the gas supply. In this proposed system there are mainly two units, GSM modem and microcontroller unit. GSM modem can be configured by standard GSM AT command set for sending and receiving SMS and getting modem status. Depending upon the gas sensor output, microcontroller can send message to the LPG plant manager and also depending upon the message received the microcontroller unit will control the devices and report the device status to the user as SMS. Keywords: GSM, LPG, MQ-6 54

2 I. INTRODUCTION In the recent past, both the GSM technology and the embedded system technologies have been rapidly growing in the industrial world. The union of these two technologies can release many synergies. The following tangible benefits can be expected, if an embedded system, controlling a local machine, is integrated with the GSM. The embedded system can be remotely monitored by using the standard GSM technology. Malfunctions of the embedded system can be diagnosed without having to dispatch a maintenance engineer to the site for the purpose of acquiring diagnostic information [1]. Almost all gas leak detection, monitoring and alarm systems are of invasive type by their very design and costly affairs. Such systems are hardly affordable by small & mid size commercial establishments and common households, in particular LPG whether directly from cylinders or piped or piped natural gas from the city gas distribution system. This paper is intended to offer a simple way for the detection of such gas. It provides an explanation of both the principles involved and the instrumentation needed for satisfactory protection of personnel, plant and environment. II. HARDWARE DEVELOPMENT Fig. 1: Proposed Block Diagram of the System Figure 1 shows block diagram of the system. Here a microcontroller will act as Master of the network. The microcontrollers with sensor interface act as slaves of the network. Sensors are interfaced to slave microcontrollers through respective signal conditioning circuits. Communication between Master and Slaves can be carried out by polling method. The Master initiates a communication request to a Slave Node by addressing that unit. The Slave addressed by the Master will respond by checking the status of sensor [2]. 55

3 Here a Personal Computer is also connected to this multi-dropping network through a RS-485 to RS-232 converter. This PC is used to monitor and display status of each sensor. The master controller is capable of communicating with RS-485 network, RS-232 connection to a local PC & to a GSM network via external GSM modem or a modem provided by a mobile phone. Master gets the alarm condition at any node via the alarm message on RS-485 network & comes into action. It will send the information of the alarm node number to the local PC via RS-232 port & send alarm SMS to the given number of the plant manager with the node number. In fact the respective node will take corrective action on its own by turning OFF the gas valve using a solenoid actuator, as soon as the leakage is detected. The alarms & SMS are for the indication to the plant manager about the impeding danger. III. GAS SENSING & CONTROL CIRCUIT Fig. 2: Gas Sensing & Control circuit With reference to Figure 2, the output of gas sensor is connected to the comparator. The output of comparator is given to the slave Microcontroller 89S52. If there is no gas leakage then output of comparator is logic 1. If there is gas leakage then output of comparator is logic 0. When Slave reads logic 1, it sends OK signal and when it reads logic 0, it sends EMERGENCY signal whenever Master demands it and activates a solenoid valve to shut off the gas supply[6][7]. IV. SOFTWARE DEVELOPMENT In this section we developed the software part of the system. The following point gives the brief idea about algorithm of various parts and their flow chart for software design. 4.1 Algorithms a) Algorithm for operation of Master Controller 1. Select GSM using analog switch(4053) 2. Initialize GSM 56

4 3. Switch to RS-485 in RX mode 4. Wait for gas sensor (P1.0) low or alarm from RS If alarm switch to GSM. If self alarm send self address else sent slave address to GSM. 6. Switch back to RS-485 in RX mode [6]. The flow chart of the Master controller shown in Figure Flowcharts Fig. 3: Flow chart for Master Controller 57

5 b) Algorithm for operation of Send alarm for Slave controller 1. Send alarm for slave. 2. Get slave address received from slave. 3. Store slave address in buffer with message. 4. Send SMS to GSM Modem. 5. Return to main program The flow chart of the Slave controller for sending SMS shown in Figure 4. Fig. 4: Flow chart for Slave SMS c) Algorithm for operation of Interrupt Service Routine 1. Check if Transmit Interrupt bit is Set. 2. If Receive Interrupt bit is set store data in buffer. 3. Copy character to data buffer. 4. Return to main program. The flow chart of the Interrupt service routine shown in Figure 5. 58

6 Fig. 5: Flow chart for Interrupt Service Routine d) Algorithm for operation of GSM Modem 1. Initialize GSM modem. 2. Send AT commands on serial port. 3. Check whether GSM is properly initialized. 4. Check for timeout. 5. If GSM modem is properly initialized send configuration commands to transmit messages & get responses. 6. Return to main program. The flow chart of the GSM Modem working shown in Figure 6 Fig. 6: Flow chart for GSM Modem 59

7 IV. RESULTS The Emergency Gas leakage Message from Master Microcontroller (Node55) is shown in figure 7. Fig. 7: Emergency Gas leakage Message from Master Microcontroller (Node55) The Emergency Gas leakage Message from slave Microcontroller (Node33) is shown in figure 8. Fig. 8: Emergency Gas leakage Message from Slave Microcontroller(Node33) Emergency Gas leakage Message to Mobile Phone is shown in figure 9. Fig. 9: Emergency Gas leakage Message to Mobile Phone of Plant Manager 60

8 V. CONCLUSION The embedded system can be remotely monitored by using the standard GSM technology. Malfunctions of the embedded system can be diagnosed without having to dispatch a maintenance engineer to the site for the purpose of acquiring diagnostic information. Almost all gas leak detection, monitoring and alarm systems are of invasive type by their very design and costly affairs. Such systems are hardly affordable by small & mid size commercial establishments and common households, in particular LPG whether directly from cylinders or piped or piped natural gas from the city gas distribution system The gas detection technique has a wide range of potential uses in the petrochemical industry, all of which have positive benefits for the owner of the plant. Thus the designed system satisfies its main aim to provide automatic control for gas leak with its lucid design. It also provides cost effective as well as highest reliable solution for users. Accidents due to leakage of LPG can be very dangerous. With a small mistake they may take lives of our loved ones. Consequences might be much more severe if such an incident takes place in an LPG plant or apartment system. This proposed system can be a solution to any hazards caused by LPG leak. REFERENCES [1] Peng Zhang, Data Communications in Distributed Control System, Industrial Control Technology 2008,Pages [2] A.H.G Al-Dhaher, Integrating hardware and software for the development of microcontroller based systems, Microprocessors and Microsystems, Volume 25, Issue 7, 15 October 2001, Pages [3] Hamit Erdem, Implementation of software-based sensor linearization algorithms on low-cost microcontrollers Original Research Article ISA Transactions, Volume 49, Issue 4, October 2010,Pages [4] Jan Axelson, Serial Port Complete Programming And Circuits For Rs-232 And Rs-485 Links And Networks, Penram International Publishing (India) Pvt.Ltd. [5] Muhammad Ali Mazidi And Janice Gillispie Mazidi, The 8051 Microcontroller And Embedded Systems, Pearson Education (Singapore) Pte.Ltd. [6] Muda, R. (2009). Simulation and measurement of carbon dioxide exhaust emissions using an optical- fibre-based mid-infrared point sensor, Journal of Optics A: Pure and Applied Optics, 11(1) [7] Vitz, E. (1995), Semiconductor Gas Sensors as GC detectors and Breathalyzers, Journal of Chemical Education, 72(920) [8] Breuer, W, Becker, W, Deprez, J, Drope, E, Schmauch, H. (1979) Electrochemical gas detector and method of using same, United States Patent