Okay, so here is my first attempt at jotting down the details of one of my projects for you. This one is one of my personal favorites and I expect an extremely reliable energy meter once I finish reviewing the coding part of the meter.
Basically, I have used an ASIC chip from Texas Instruments, which measures apparent energy (power rather!) instead of energy delivered to the consumer. Due to inherent losses of a transmission line, a part of the electrical energy generated at the power station is reflected back, while the part that remains is delivered to the household. The traditional meters measure the energy delivered/consumed by the consumer, and not the energy generated. Hence, the actual cost of generation of energy is never recovered. It is estimated that India has lost trillions of rupees due to this faulty meters.
The chip from TI is MSP430FE427, which has an inbuilt embedded system processor (ESP), 16-bit hardware multiplier, three 16-bit sigma-delta ADCs, inbuilt LCD driver, UART/USART comm ports and an arrangement to interface the JTAG emulator.
While designing the circuit, following points have to be taken care of:
1. Measuring the voltage and current from the source as accurately as possible
2. Providing the +3.3 V to the digital circuitry for its proper functioning
3. See to it that the 230V from the source doesn't reach/affect/overload the digital circuitry in any form
4. Displaying the apparent power (kVAh) on the LCD
5. Measure the current and voltage in both - the phase and the neutral lines, to ensure no tampering has been done with circuit and prevent theft of electricity
(As a further extension to this project, I have also thought of interfacing it with a bluetooth/zigbee module in order to enhance the ease of using the meter)
So the entire project has been divided into 5 different modules for ease of implementation:
1. Power supply section - To provide 3.3 V to the circuit and ensure that the supply from the mains does not affect the circuit
2. Analog Section - To provide the voltage and current from the mains for measurement purpose to the current transformers
3. Controller Section - Interpret the measured values, multiply them, process them taking care of the calibration parameters and display the result on the LCD
4. PCB Design - All the 3 circuits above should be properly integrated into a single chip, which facilitates further entension to the project as I described earlier
5. Coding of the ESP and the ASIC chip - The heart of the entire project, this part contains codes pertaining to different tasks that need to be performed in the processor
I am using IAR Embedded Workbench for the coding part. The cracked version is easily available for download. I downloaded part of the code from a blog, but didn't find it much useful. I am using it as a reference and develop my own code altogether.
I have finished the design, PCB design as well as part of the coding. I will try and upload the snaps of the circuit and the PCB design asap. The code is going to take atleast another 3 months to finalize. I will keep updating about my progress. Stay tuned!!
(P.S.: I know most of you might not understand what I've written here, for its pretty incomprehensible. But this was the best I could write. And perhaps, this project is too big to write it on a blog, so all I have done is given a bird's eye view)
I'd appreciate further suggestions/queries from you all. Do not hesitate to write me on varunshah444 at gmail dot com
Basically, I have used an ASIC chip from Texas Instruments, which measures apparent energy (power rather!) instead of energy delivered to the consumer. Due to inherent losses of a transmission line, a part of the electrical energy generated at the power station is reflected back, while the part that remains is delivered to the household. The traditional meters measure the energy delivered/consumed by the consumer, and not the energy generated. Hence, the actual cost of generation of energy is never recovered. It is estimated that India has lost trillions of rupees due to this faulty meters.
The chip from TI is MSP430FE427, which has an inbuilt embedded system processor (ESP), 16-bit hardware multiplier, three 16-bit sigma-delta ADCs, inbuilt LCD driver, UART/USART comm ports and an arrangement to interface the JTAG emulator.
While designing the circuit, following points have to be taken care of:
1. Measuring the voltage and current from the source as accurately as possible
2. Providing the +3.3 V to the digital circuitry for its proper functioning
3. See to it that the 230V from the source doesn't reach/affect/overload the digital circuitry in any form
4. Displaying the apparent power (kVAh) on the LCD
5. Measure the current and voltage in both - the phase and the neutral lines, to ensure no tampering has been done with circuit and prevent theft of electricity
(As a further extension to this project, I have also thought of interfacing it with a bluetooth/zigbee module in order to enhance the ease of using the meter)
So the entire project has been divided into 5 different modules for ease of implementation:
1. Power supply section - To provide 3.3 V to the circuit and ensure that the supply from the mains does not affect the circuit
2. Analog Section - To provide the voltage and current from the mains for measurement purpose to the current transformers
3. Controller Section - Interpret the measured values, multiply them, process them taking care of the calibration parameters and display the result on the LCD
4. PCB Design - All the 3 circuits above should be properly integrated into a single chip, which facilitates further entension to the project as I described earlier
5. Coding of the ESP and the ASIC chip - The heart of the entire project, this part contains codes pertaining to different tasks that need to be performed in the processor
I am using IAR Embedded Workbench for the coding part. The cracked version is easily available for download. I downloaded part of the code from a blog, but didn't find it much useful. I am using it as a reference and develop my own code altogether.
I have finished the design, PCB design as well as part of the coding. I will try and upload the snaps of the circuit and the PCB design asap. The code is going to take atleast another 3 months to finalize. I will keep updating about my progress. Stay tuned!!
(P.S.: I know most of you might not understand what I've written here, for its pretty incomprehensible. But this was the best I could write. And perhaps, this project is too big to write it on a blog, so all I have done is given a bird's eye view)
I'd appreciate further suggestions/queries from you all. Do not hesitate to write me on varunshah444 at gmail dot com
I'd like to appreciate the help and involvement of my project partners Parvez Shaikh, Anup Patel and Vivek Shah in the project. Without them, this project would've been next to impossible. To be frank, They've done most of the hardwork while I have just been a spectator at times. Thanks guys, thanks a lot!!
ReplyDelete1) 32 bit hardware multiplier
ReplyDelete2) +3.6 volts is provided to the circuitry(used twice)
3) Analog Section: It provides the current and voltage to the Processor and not CT.
4) Controller section: Here we have interfaced necessary component with the controller. For eg. JTAG, Uart, Crystal,etc. Most of the calibration part is covered in software.