DanyR
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This is a small project of mine: a single phase AC wattmeter.
This meter is built with as less as components possible. It is of course a little limited in range, accuracy and stability.
It is made for 230V~ (rms), max 2.5A~ (rms) and 50Hz, but is rather easily adaptable to other voltages, currents and frequencies. It can handle both sinusoidal and non sinusoidal voltages and currents, both with and without
DC component.
It measures:
the Rms voltage (unit: Volt)
the Rms current (unit: Ampère)
the apparent power consumption (unit: VoltAmpère: VA, the product of both the rms Voltage and the Rms current). This value is also called “Complex power”.
the real power consumption (unit: Watt) (= the one that you are going to pay for)
the power factor (no unit, ratio of real power to the apparent power), is the same as “cosΦ” (cos phi) for sinusoidal voltages and currents.
All values are shown on an LCD, except for the Apparent (Complex) power. The meter measures once per second.
Additionally there is one push button to set the “zero” point for the AD convertors. The values of these zero points are stored in Eeprom and recalled after startup of the PIC.
Important: A number of versions of the circuit diagram are presented in the .pdf file. A number of them are NOT MAINS ISOLATED. Be carefull!
View attachment WattMeter.pdf
Two versions of the software are added:
- one with simple 'delays' between measurements, and
- one with measurements in an interrupt routine.
View attachment WattMeter.zip
View attachment WattMeter_Interrupt.zip
The software is in Pascal, the compiler I use is the mikroPascal compiler.
I you have comments, please let me know.
Have fun!
This meter is built with as less as components possible. It is of course a little limited in range, accuracy and stability.
It is made for 230V~ (rms), max 2.5A~ (rms) and 50Hz, but is rather easily adaptable to other voltages, currents and frequencies. It can handle both sinusoidal and non sinusoidal voltages and currents, both with and without
DC component.
It measures:
the Rms voltage (unit: Volt)
the Rms current (unit: Ampère)
the apparent power consumption (unit: VoltAmpère: VA, the product of both the rms Voltage and the Rms current). This value is also called “Complex power”.
the real power consumption (unit: Watt) (= the one that you are going to pay for)
the power factor (no unit, ratio of real power to the apparent power), is the same as “cosΦ” (cos phi) for sinusoidal voltages and currents.
All values are shown on an LCD, except for the Apparent (Complex) power. The meter measures once per second.
Additionally there is one push button to set the “zero” point for the AD convertors. The values of these zero points are stored in Eeprom and recalled after startup of the PIC.
Important: A number of versions of the circuit diagram are presented in the .pdf file. A number of them are NOT MAINS ISOLATED. Be carefull!
View attachment WattMeter.pdf
Two versions of the software are added:
- one with simple 'delays' between measurements, and
- one with measurements in an interrupt routine.
View attachment WattMeter.zip
View attachment WattMeter_Interrupt.zip
The software is in Pascal, the compiler I use is the mikroPascal compiler.
I you have comments, please let me know.
Have fun!
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