Comment summary #28
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Comment 271 ... 280
| date | article | author | comment |
| 10 maa 2016 21:25:41 | Arduino wattmeter | Freddy | Then you have a lot of work to do every time you change the load. Or I don't understand your intentions. |
| 10 maa 2016 04:19:58 | Arduino wattmeter | angel | What may be the problem if I calibrate the meter every time I change the load? Thank you |
| 09 maa 2016 14:23:17 | Arduino wattmeter | Freddy | I think you have to accept this minor error. The wattmeter lacks an auto-zero function like multimeters have. |
| 08 maa 2016 19:34:23 | Arduino wattmeter | Wolfram Fischer | Hi, i put instead 1n4148 bas416 into the protection circuit, but still the same: -0.01V and 0.01A Even with no diodes at all! |
| 08 maa 2016 15:32:55 | Arduino wattmeter | Freddy | @jesso, follow the parameters explanation in table 2. The energy measurement is in essence very simple: Multiply each sampled voltage, current and the time between samples (V*I*t). And the energy is calculated by continues adding these products. Thats it! In a real world program like this wattmeter the calculations must be optimized: To prevent time consuming floating point calculations, the calculations with the sampled data are done with int numbers. The processing of the sample time, conversions to real float parameters are done at a later time, for example when the parameters are displayed. |
| 08 maa 2016 15:10:49 | Arduino wattmeter | Freddy | @ jacky, it is too long ago to remember all the details, but here is a general description. A lot of initial values of parameters don't have a precise setting and are set at a value that is within reason. In the program itself the values are calculated. The part of the program where the parameters you're referring to are used is the frequency counter and signal synchronisation. The purpose of synchronisation is to stabilize the reading and increase the accuracy of measurements on periodic signals. For example: the average value of sinewave measured over one period is zero. The average value of the same sinewave over 1¼ period is not zero. If the program detects a AC wave or ripple, then it calculates the parameters during a whole number of periods. Therefore the number of periods ant the integration time must be recorded. I hope this explanation is sufficient. |
| 08 maa 2016 10:49:57 | Arduino wattmeter | Jesso | Hi, I would first of all want to congratulate you on your work. An excellent work. I am a student in DUT(TWO-YEAR TECHNICAL DEGREE) I am work on a project of calculation of the energy. I am novice in programming. I would want to know if you can help me to extract just the part concerning the calculation of energy because I am lost between lines. Thanks in advance |
| 08 maa 2016 09:58:06 | Arduino wattmeter | Jacky GOUSART | Bonjour Freddy, .Felicitations pour votre travail et pour la publication du code detaillé du \\"WATTMETRE with Arduino\\" Je suis en train de relire la partie du code ci dessous A votre avis, pourquoi ces lignes et que veulent dire les éléments Je ne comprends pas pourquoi les valeurs des périodes counter (5 et 7) et pourquoi sont elles différentes entres tension et courant idem pour la synchronisation (pourquoi synchro ? et pourquoi ces valeurs 1000 si vous pouvez" m'éclairer", Hello Freddy, Congratulations for your work and for the publication of Detailed Code \\ "WATTMETRE with Arduino \\" I am trying to read the part of the code below In your opinion, why these lines and what do the elements I do not understand why the values of the time counter (5 and 7) and why are they among different voltage and current ditto for synchronization (sync why and why these values 1000 if you can "help me" /*** Voltage frequency measurement ***/ int vfmUpperTh = 10; // Upper threshold voltage int vfmLowerTh = -10; // Lower threshold voltage boolean vfmDir = false; // Direction voltageunsigned int vfmPeriods = 7; // Periods counter unsigned int vfmPeriodsTime = 1000; // Synchronized with periods time unsigned int vfmTime = 1000; // Time counter /*** Current frequency measurement ***/ int cfmUpperTh = 10; // Upper threshold current int cfmLowerTh = -10; // Lower threshold current boolean cfmDir = false; // Direction currentunsigned int cfmPeriods = 5; // Periods counter unsigned int cfmPeriodsTime = 1000; // Synchronized with periods time unsigned int cfmTime = 1000; // Time counter . Pending read. Thanks in advance. jacky jacky.gousart@gmail.com |
| 07 maa 2016 15:17:10 | Arduino wattmeter | Freddy | I already explained it in my comment of 6 march. It can't be compensated due to the unstable nature of this offset voltage. |
| 07 maa 2016 05:39:59 | Arduino wattmeter | Wolfram Fischer | isn't it possible to adjust this offset in the software? |