13-08-2014, 04:28 PM
RROJECT REPORT ON REMOTE ENERGY MONITORING, PROFILING AND CONTROL THROUGH GSM NETWOR
[attachment=66627]
ABSTRACT
This paper presents design and development of a GSM based energy monitoring, profiling and control system. Our system integrates digital energy meters installed at consumer unit with an electric supply company’s energy monitoring system. Single phase or three phase digital electric meter can be used with indigenously developed add on transmission module, which takes the meter reading and utilizes the GSM network to transmit the energy usage reading using Short Message Service (SMS) back to the energy supplier. At the supplier end, an energy monitoring system is used to manage all received meter readings, compute the billing cost, update the database and maintain an energy consumption profile for each user. Various alerts and control can also be generated by the supplier. A simple, cost effective and reliable working prototype of complete system has been developed using digital energy meter manufactured by MicroTech Limited, Pakistan to demonstrate an efficient and transparent means of automatic meter reading, billing and notification through the use of GSM network.
Introduction
The conventional metering system requires the supplier company to send personnel who manually read and record the energy consumption, so billing can be done accordingly. The manual reading system suffers from a wide variety of disadvantages, which tenders it inefficient. It requires a large number of meter readers to collect reading from all consumers, hence the frequency of meter reading acquirement is low, that is, usually once a month. Moreover, with human involvement, it is prone to human errors as well as tampering of records.
This leads to non-transparency in the metering system. To devise an efficient metering system, the concept of Automatic Meter Reading (AMR) and Energy Profiling System (EPS) [1-2] originated, which provide an effective means of energy consumption information collection, and its analysis, for accurate billing. A plethora of technologies can be utilized for the implementation of such a system, each having its own pros and cons. Radio frequency based EPS can make use of Handheld, Mobile, and Fixed network. In handheld and touch based EPS, a handheld computer equipped with a transceiver is used (radio frequency or touch) to collect readings, but it does not make optimum use of the AMR capable meters, as meter reading personnel are required.
Mobile or Drive-by meter reading is another approach where a reading device is installed in a vehicle. Due to the short range of mobility, it again requires a team for collection of meter readings. AMR can also be implemented by making use of Power Line Communication (PLC) [3-4], but it has an inherent disadvantage of interference and noise, which deems it unreliable. Wi-Fi, ZigBee and 3G technologies [5-6] have also been used for transmission of metering information, but have not being widespread as they require installation of facility/ access points to cover the designated areas and thus do not provide a cost effective solution in existing environments. Our indigenously developed GSM transmission module induce transparency in the current meter reading system, by facilitating low cost real time monitoring of consumer energy consumption. Automation would lead to an efficient energy metering system by removing human errors.
Micro Processor (µp)
A silicon chip contains a CPU. In the world of personal computers, the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor. Microprocessors also control the logic of almost all digital devices, from clock radios to fuel-injection systems for automobiles.
Digital Signal Processors (DSPs)
Digital Signal Processors is one which performs scientific and mathematical operation. Digital Signal Processor chips - specialized microprocessors with architectures designed specifically for the types of operations required in digital signal processing. Like a general-purpose microprocessor, a DSP is a programmable device, with its own native instruction code. DSP chips are capable of carrying out millions of floating point operations per second, and like their better-known general-purpose cousins, faster and more powerful versions are continually being introduced. DSPs can also be embedded within complex "system-on-chip" devices, often containing both analog and digital circuitry.
Reduced Instruction Set Computer (RISC)
A RISC (reduced instruction set computer) is a microprocessor that is designed to perform a smaller number of types of computer instruction so that it can operate at a higher speed (perform more million instructions per second, or millions of instructions per second). Since each instruction type that a computer must perform requires additional transistors and circuitry, a larger list or set of computer instructions tends to make the microprocessor more complicated and slower in operation.
Besides performance improvement, some advantages of RISC and related design improvements are:
Modern uses of the Harvard architecture
The principal advantage of the pure Harvard architecture - simultaneous access to more than one memory system - has been reduced by modified Harvard processors using modern CPU cache systems. Relatively pure Harvard architecture machines are used mostly in applications where tradeoffs, such as the cost and power savings from omitting caches, outweigh the programming penalties from having distinct code and data address spaces.
Digital signal processors (DSPs) generally execute small, highly-optimized audio or video processing algorithms. They avoid caches because their behavior must be extremely reproducible. The difficulties of coping with multiple address spaces are of secondary concern to speed of execution. As a result, some DSPs have multiple data memories in distinct address spaces to facilitate SIMD and VLIW processing. Texas Instruments TMS320 C55x processors, as one example, have multiple parallel data busses (two write, three read) and one instruction bus.
Microcontrollers are characterized by having small amounts of program (flash memory) and data (SRAM) memory, with no cache, and take advantage of the Harvard architecture to speed processing by concurrent instruction and data access. The separate storage means the program and data memories can have different bit depths, for example using 16-bit wide instructions and 8-bit wide data. They also mean that instruction pre-fetch can be performed in parallel with other activities. Examples include, the AVR by Atmel Corp, the PIC by Microchip Technology, Inc. and the ARM Cortex-M3 processor (not all ARM chips have Harvard architecture).
Even in these cases, it is common to have special instructions to access program memory as data for read-only tables, or for reprogramming.
Von-Neumann Architecture
A computer has a single, common memory space in which both program instructions and data are stored. There is a single internal data bus that fetches both instructions and data. They cannot be performed at the same time
Additional Feature-GPS
After reviewing literature about meter thefts, an additional feature was added to the system to counter these thefts. Location of the meter, as received by the Global Positioning System, is transmitted to the server end after specific intervals. The location received is compared to the location stored in the database, and in case of a mismatch, corresponding alert is generated. Use of GPS System in the system is an efficient measure that forestalls the meter theft, adding security to the system
Internal Features
The ARM7TDMI-S is a general purpose 32-bit microprocessor, which offers high performance and very low power consumption. The ARM architecture is based on Reduced Instruction Set Computer (RISC) principles, and the instruction set and related decode mechanism are much simpler than those of micro-programmed Complex Instruction Set Computers. This simplicity results in a high instruction throughput and impressive real-time interrupt response from a small and cost-effective processor core. Pipeline techniques are employed so that all parts of the processing and memory systems can operate continuously. Typically, while one instruction is being executed, its successor is being decoded, and a third instruction is being fetched from memory. The ARM7TDMI-S processor also employs a unique architectural strategy known as THUMB, which makes it ideally suited to high-volume applications with memory restrictions, or applications where code density is an issue. The key idea behind THUMB is that of a super-reduced instruction set. Essentially, the ARM7TDMI-S processor has two instruction sets:
• The standard 32-bit ARM instruction set.
• A 16-bit THUMB instruction set.
The THUMB set’s 16-bit instruction length allows it to approach twice the density of standard ARM code while retaining most of the ARM’s performance advantage over a traditional 16-bit processor using 16-bit registers. This is possible because THUMB code operates on the same 32-bit register set as ARM code. THUMB code is able to provide up to 65% of the code size of ARM, and 160% of the performance of an equivalent ARM processor connected to a 16-bit memory system.
FLASH PROGRAMMING ISSSUES
Since the Flash memory does not allow accesses during programming and erase operations, it is necessary for the MAM to force the CPU to wait if a memory access to a Flash address is requested while the Flash module is busy. (This is accomplished by asserting the ARM7TDMI-S local bus signal CLKEN.) Under some conditions, this delay could result in a Watchdog time-out. The user will need to be aware of this possibility and take steps to insure that an unwanted Watchdog reset does not cause a system failure while programming or erasing the Flash memory.
In order to preclude the possibility of stale data being read from the Flash memory, the LPC2141/2/4/6/8 MAM holding latches are automatically invalidated at the beginning of any Flash programming or erase operation. Any subsequent read from a Flash address will cause a new fetch to be initiated after the Flash operation has completed.
LIQUID CRISTAL DISPLAY
A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. Each pixel consists of a column of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. Without the liquid crystals between them, light passing through one would be blocked by the other. The liquid crystal twists the polarization of light entering one filter to allow it to pass through the other.
A program must interact with the outside world using input and output devices that communicate directly with a human being. One of the most common devices attached to an controller is an LCD display. Some of the most common LCDs connected to the contollers are 16X1, 16x2 and 20x2 displays. This means 16 characters per line by 1 line 16 characters per line by 2 lines and 20 characters per line by 2 lines, respectively.
Shapes and S
available. Line lengths of 8, 16, 20, 24, 32 and 40 characters are all standard, in one, two
Many microcontroller devices use 'smart LCD' displays to output visual information. LCD displays designed around LCD NT-C1611 module, are inexpensive, easy to use, and it is even possible to produce a readout using the 5X7 dots plus cursor of the display. They have a standard ASCII set of characters and mathematical symbols. For an 8-bit data bus, the display requires a +5V supply plus 10 I/O lines (RS RW D7 D6 D5 D4 D3 D2 D1 D0). For a 4-bit data bus it only requires the supply lines plus 6 extra lines(RS RW D7 D6 D5 D4). When the LCD display is not enabled, data lines are tri-state and they do not interfere with the operation of the microcontroller
SERIAL COMMUNICATION
In order to connect micro controller to a modem or a pc to modem a serial port is used. Serial is a very common protocol for device communication that is standard on almost every PC. Most computers include two RS-232 based serial ports. Serial is also a common communication protocol that is used by many devices for instrumentation; numerous GPIB-compatible devices also come with an RS-232 port. Furthermore, serial communication can be used for data acquisition in conjunction with a remote sampling device.
The concept of serial communication is simple. The serial port sends and receives bytes of information one bit at a time. Although this is slower than parallel communication, which allows the transmission of an entire byte at once, it is simpler and can be used over longer distances. For example, the IEEE 488 specifications for parallel communication state that the cabling between equipment can be no more than 20 meters total, with no more than 2 meters between any two devices. Serial, however, can extend as much as 1200 meters.
Typically, serial is used to transmit ASCII data. Communication is completed using 3 transmission lines: (1) Ground, (2) Transmit, and (3) Receive. Since serial is asynchronous, the port is able to transmit data on one line while receiving data on another. Other lines are available for handshaking, but are not required. The important serial characteristics are baud rate, data bits, stop bits, and parity. For two ports to communicate, these parameters must match
TDMA in brief
In late1980’s, as a search to convert the existing analog network to digital as a means to improve capacity, the cellular telecommunications industry association chose TDMA over FDMA. Time Division Multiplex Access is a type of multiplexing where two or more channels of information are transmitted over the same link by allocating a different time interval for the transmission of each channel. The most complex implementation using TDMA principle is of GSM’s (Global System for Mobile communication). To reduce the effect of co-channel interference, fading and multipath, the GSM technology can use frequency hopping, where a call jumps from one channel to another channel in a short interval.
GSM Modem
A GSM modem is a wireless modem that works with a GSM wireless network. A wireless modem behaves like a dial-up modem. The main difference between them is that a dial-up modem sends and receives data through a fixed telephone line while a wireless modem sends and receives data through radio waves.
Building Projects and Creating a HEX Files
Typical, the tool settings under Options – Target are all you need to start a new application. You may translate all source files and line the application with a click on the Build Target toolbar icon. When you build an application with syntax errors, µVision2 will display errors and warning messages in the Output Window – Build page. A double click on a message line opens the source file on the correct location in a µVision2 editor window. Once you have successfully generated your application you can start debugging.
After you have tested your application, it is required to create an Intel HEX file to download the software into an EPROM programmer or simulator. µVision2 creates HEX files with each build process when Create HEX files under Options for Target – Output is enabled. You may start your PROM programming utility after the make process when you specify the program under the option Run User Program #1.
CPU Simulation
µVision2 simulates up to 16 Mbytes of memory from which areas can be mapped for read, write, or code execution access. The µVision2 simulator traps and reports illegal memory accesses. In addition to memory mapping, the simulator also provides support for the integrated peripherals of the various 8051 derivatives. The on-chip peripherals of the CPU you have selected are configured from the Device
[attachment=66627]
ABSTRACT
This paper presents design and development of a GSM based energy monitoring, profiling and control system. Our system integrates digital energy meters installed at consumer unit with an electric supply company’s energy monitoring system. Single phase or three phase digital electric meter can be used with indigenously developed add on transmission module, which takes the meter reading and utilizes the GSM network to transmit the energy usage reading using Short Message Service (SMS) back to the energy supplier. At the supplier end, an energy monitoring system is used to manage all received meter readings, compute the billing cost, update the database and maintain an energy consumption profile for each user. Various alerts and control can also be generated by the supplier. A simple, cost effective and reliable working prototype of complete system has been developed using digital energy meter manufactured by MicroTech Limited, Pakistan to demonstrate an efficient and transparent means of automatic meter reading, billing and notification through the use of GSM network.
Introduction
The conventional metering system requires the supplier company to send personnel who manually read and record the energy consumption, so billing can be done accordingly. The manual reading system suffers from a wide variety of disadvantages, which tenders it inefficient. It requires a large number of meter readers to collect reading from all consumers, hence the frequency of meter reading acquirement is low, that is, usually once a month. Moreover, with human involvement, it is prone to human errors as well as tampering of records.
This leads to non-transparency in the metering system. To devise an efficient metering system, the concept of Automatic Meter Reading (AMR) and Energy Profiling System (EPS) [1-2] originated, which provide an effective means of energy consumption information collection, and its analysis, for accurate billing. A plethora of technologies can be utilized for the implementation of such a system, each having its own pros and cons. Radio frequency based EPS can make use of Handheld, Mobile, and Fixed network. In handheld and touch based EPS, a handheld computer equipped with a transceiver is used (radio frequency or touch) to collect readings, but it does not make optimum use of the AMR capable meters, as meter reading personnel are required.
Mobile or Drive-by meter reading is another approach where a reading device is installed in a vehicle. Due to the short range of mobility, it again requires a team for collection of meter readings. AMR can also be implemented by making use of Power Line Communication (PLC) [3-4], but it has an inherent disadvantage of interference and noise, which deems it unreliable. Wi-Fi, ZigBee and 3G technologies [5-6] have also been used for transmission of metering information, but have not being widespread as they require installation of facility/ access points to cover the designated areas and thus do not provide a cost effective solution in existing environments. Our indigenously developed GSM transmission module induce transparency in the current meter reading system, by facilitating low cost real time monitoring of consumer energy consumption. Automation would lead to an efficient energy metering system by removing human errors.
Micro Processor (µp)
A silicon chip contains a CPU. In the world of personal computers, the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor. Microprocessors also control the logic of almost all digital devices, from clock radios to fuel-injection systems for automobiles.
Digital Signal Processors (DSPs)
Digital Signal Processors is one which performs scientific and mathematical operation. Digital Signal Processor chips - specialized microprocessors with architectures designed specifically for the types of operations required in digital signal processing. Like a general-purpose microprocessor, a DSP is a programmable device, with its own native instruction code. DSP chips are capable of carrying out millions of floating point operations per second, and like their better-known general-purpose cousins, faster and more powerful versions are continually being introduced. DSPs can also be embedded within complex "system-on-chip" devices, often containing both analog and digital circuitry.
Reduced Instruction Set Computer (RISC)
A RISC (reduced instruction set computer) is a microprocessor that is designed to perform a smaller number of types of computer instruction so that it can operate at a higher speed (perform more million instructions per second, or millions of instructions per second). Since each instruction type that a computer must perform requires additional transistors and circuitry, a larger list or set of computer instructions tends to make the microprocessor more complicated and slower in operation.
Besides performance improvement, some advantages of RISC and related design improvements are:
Modern uses of the Harvard architecture
The principal advantage of the pure Harvard architecture - simultaneous access to more than one memory system - has been reduced by modified Harvard processors using modern CPU cache systems. Relatively pure Harvard architecture machines are used mostly in applications where tradeoffs, such as the cost and power savings from omitting caches, outweigh the programming penalties from having distinct code and data address spaces.
Digital signal processors (DSPs) generally execute small, highly-optimized audio or video processing algorithms. They avoid caches because their behavior must be extremely reproducible. The difficulties of coping with multiple address spaces are of secondary concern to speed of execution. As a result, some DSPs have multiple data memories in distinct address spaces to facilitate SIMD and VLIW processing. Texas Instruments TMS320 C55x processors, as one example, have multiple parallel data busses (two write, three read) and one instruction bus.
Microcontrollers are characterized by having small amounts of program (flash memory) and data (SRAM) memory, with no cache, and take advantage of the Harvard architecture to speed processing by concurrent instruction and data access. The separate storage means the program and data memories can have different bit depths, for example using 16-bit wide instructions and 8-bit wide data. They also mean that instruction pre-fetch can be performed in parallel with other activities. Examples include, the AVR by Atmel Corp, the PIC by Microchip Technology, Inc. and the ARM Cortex-M3 processor (not all ARM chips have Harvard architecture).
Even in these cases, it is common to have special instructions to access program memory as data for read-only tables, or for reprogramming.
Von-Neumann Architecture
A computer has a single, common memory space in which both program instructions and data are stored. There is a single internal data bus that fetches both instructions and data. They cannot be performed at the same time
Additional Feature-GPS
After reviewing literature about meter thefts, an additional feature was added to the system to counter these thefts. Location of the meter, as received by the Global Positioning System, is transmitted to the server end after specific intervals. The location received is compared to the location stored in the database, and in case of a mismatch, corresponding alert is generated. Use of GPS System in the system is an efficient measure that forestalls the meter theft, adding security to the system
Internal Features
The ARM7TDMI-S is a general purpose 32-bit microprocessor, which offers high performance and very low power consumption. The ARM architecture is based on Reduced Instruction Set Computer (RISC) principles, and the instruction set and related decode mechanism are much simpler than those of micro-programmed Complex Instruction Set Computers. This simplicity results in a high instruction throughput and impressive real-time interrupt response from a small and cost-effective processor core. Pipeline techniques are employed so that all parts of the processing and memory systems can operate continuously. Typically, while one instruction is being executed, its successor is being decoded, and a third instruction is being fetched from memory. The ARM7TDMI-S processor also employs a unique architectural strategy known as THUMB, which makes it ideally suited to high-volume applications with memory restrictions, or applications where code density is an issue. The key idea behind THUMB is that of a super-reduced instruction set. Essentially, the ARM7TDMI-S processor has two instruction sets:
• The standard 32-bit ARM instruction set.
• A 16-bit THUMB instruction set.
The THUMB set’s 16-bit instruction length allows it to approach twice the density of standard ARM code while retaining most of the ARM’s performance advantage over a traditional 16-bit processor using 16-bit registers. This is possible because THUMB code operates on the same 32-bit register set as ARM code. THUMB code is able to provide up to 65% of the code size of ARM, and 160% of the performance of an equivalent ARM processor connected to a 16-bit memory system.
FLASH PROGRAMMING ISSSUES
Since the Flash memory does not allow accesses during programming and erase operations, it is necessary for the MAM to force the CPU to wait if a memory access to a Flash address is requested while the Flash module is busy. (This is accomplished by asserting the ARM7TDMI-S local bus signal CLKEN.) Under some conditions, this delay could result in a Watchdog time-out. The user will need to be aware of this possibility and take steps to insure that an unwanted Watchdog reset does not cause a system failure while programming or erasing the Flash memory.
In order to preclude the possibility of stale data being read from the Flash memory, the LPC2141/2/4/6/8 MAM holding latches are automatically invalidated at the beginning of any Flash programming or erase operation. Any subsequent read from a Flash address will cause a new fetch to be initiated after the Flash operation has completed.
LIQUID CRISTAL DISPLAY
A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. Each pixel consists of a column of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. Without the liquid crystals between them, light passing through one would be blocked by the other. The liquid crystal twists the polarization of light entering one filter to allow it to pass through the other.
A program must interact with the outside world using input and output devices that communicate directly with a human being. One of the most common devices attached to an controller is an LCD display. Some of the most common LCDs connected to the contollers are 16X1, 16x2 and 20x2 displays. This means 16 characters per line by 1 line 16 characters per line by 2 lines and 20 characters per line by 2 lines, respectively.
Shapes and S
available. Line lengths of 8, 16, 20, 24, 32 and 40 characters are all standard, in one, two
Many microcontroller devices use 'smart LCD' displays to output visual information. LCD displays designed around LCD NT-C1611 module, are inexpensive, easy to use, and it is even possible to produce a readout using the 5X7 dots plus cursor of the display. They have a standard ASCII set of characters and mathematical symbols. For an 8-bit data bus, the display requires a +5V supply plus 10 I/O lines (RS RW D7 D6 D5 D4 D3 D2 D1 D0). For a 4-bit data bus it only requires the supply lines plus 6 extra lines(RS RW D7 D6 D5 D4). When the LCD display is not enabled, data lines are tri-state and they do not interfere with the operation of the microcontroller
SERIAL COMMUNICATION
In order to connect micro controller to a modem or a pc to modem a serial port is used. Serial is a very common protocol for device communication that is standard on almost every PC. Most computers include two RS-232 based serial ports. Serial is also a common communication protocol that is used by many devices for instrumentation; numerous GPIB-compatible devices also come with an RS-232 port. Furthermore, serial communication can be used for data acquisition in conjunction with a remote sampling device.
The concept of serial communication is simple. The serial port sends and receives bytes of information one bit at a time. Although this is slower than parallel communication, which allows the transmission of an entire byte at once, it is simpler and can be used over longer distances. For example, the IEEE 488 specifications for parallel communication state that the cabling between equipment can be no more than 20 meters total, with no more than 2 meters between any two devices. Serial, however, can extend as much as 1200 meters.
Typically, serial is used to transmit ASCII data. Communication is completed using 3 transmission lines: (1) Ground, (2) Transmit, and (3) Receive. Since serial is asynchronous, the port is able to transmit data on one line while receiving data on another. Other lines are available for handshaking, but are not required. The important serial characteristics are baud rate, data bits, stop bits, and parity. For two ports to communicate, these parameters must match
TDMA in brief
In late1980’s, as a search to convert the existing analog network to digital as a means to improve capacity, the cellular telecommunications industry association chose TDMA over FDMA. Time Division Multiplex Access is a type of multiplexing where two or more channels of information are transmitted over the same link by allocating a different time interval for the transmission of each channel. The most complex implementation using TDMA principle is of GSM’s (Global System for Mobile communication). To reduce the effect of co-channel interference, fading and multipath, the GSM technology can use frequency hopping, where a call jumps from one channel to another channel in a short interval.
GSM Modem
A GSM modem is a wireless modem that works with a GSM wireless network. A wireless modem behaves like a dial-up modem. The main difference between them is that a dial-up modem sends and receives data through a fixed telephone line while a wireless modem sends and receives data through radio waves.
Building Projects and Creating a HEX Files
Typical, the tool settings under Options – Target are all you need to start a new application. You may translate all source files and line the application with a click on the Build Target toolbar icon. When you build an application with syntax errors, µVision2 will display errors and warning messages in the Output Window – Build page. A double click on a message line opens the source file on the correct location in a µVision2 editor window. Once you have successfully generated your application you can start debugging.
After you have tested your application, it is required to create an Intel HEX file to download the software into an EPROM programmer or simulator. µVision2 creates HEX files with each build process when Create HEX files under Options for Target – Output is enabled. You may start your PROM programming utility after the make process when you specify the program under the option Run User Program #1.
CPU Simulation
µVision2 simulates up to 16 Mbytes of memory from which areas can be mapped for read, write, or code execution access. The µVision2 simulator traps and reports illegal memory accesses. In addition to memory mapping, the simulator also provides support for the integrated peripherals of the various 8051 derivatives. The on-chip peripherals of the CPU you have selected are configured from the Device