Comment summary #25
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Comment 241 ... 250
| date | article | author | comment |
| 25 apr 2016 16:40:50 | Diode measurements | Jan Spaenjers | If Ir = 1.10E-7 and if I want to calculate Vd for an Id of 10mA then: lg(0.01A/1.10E-7) = Vd/VT . VT = 26 mV by 27 ° C than Vd = 0.3 V Which is totally wrong. It should be about 0.65V or in other words Ir should be about 2.10E-14. What is going wrong in your measurements ? |
| 23 apr 2016 19:03:55 | Arduino wattmeter | Wolfram Fischer | pictures are resized now. |
| 19 apr 2016 20:34:02 | Arduino wattmeter | Freddy | @Jesso, Not sure what you exactly mean. But if you want to modify the parameters shown at startup, look at the line: byte paramPointers[4] = {0,7,13,18}; // Parameter pointer for each display line @Wolfram, Nicely done. By the way, if you are in the opportunity, can you reduce the size to the images you're linking to. They are almost 2 Mb together! |
| 19 apr 2016 17:36:44 | Arduino wattmeter | Jesso | Hello Freddy! I would really like to thank you for your answer, however I have another question. I would like to show only 4 parameters on the display (Voltage, Current, Energy and time) but I don't know how to proceed. If you have any suggestions for me, please feel free to tell me. Regards. |
| 18 apr 2016 01:54:40 | Arduino wattmeter | Wolfram Fischer | Hi, i made a Powermeter in a old Centronics-Switch Case and there are some changes to Freddys original Powermeter: Changes are: 1.: Voltage Autorange 0-50 or 50-500V 2.: Current to 50Amps 3.: D13 is now used to switch the LCD-Backlight Hi/Low after 5minutes of no button pressed 4.: A0 is used for a reverse currunt LED 5.: A1 is used for a forward current LED 6.: A2 is used for the LO-Voltage Range LED 7.: A3 is used for the HI-Voltage Range LED and the Relays to switch the input Resistor from 1Mohm to 10Mohm 8.: I use a transformer to charge a 15V LiOn Battery wich takes over if mains fail or if a mobile Work is needed. 9.: I use a 4x20 LCD with white Characters 10.: some features were added as: Energy in Wh, Charges in Ah and Charges in Ah/24h (for my Solar Panels), Time is counting in s,m,h and days (not yet on the LCD) The Arduino sketch is available here: www.mega-hz.de/forum_bilder/wattmeter_gross.ino This Device is VERY VERY good Arduino App !!! Thousends thanx to Freddy!!! regards, Wolfram. |
| 15 apr 2016 20:42:30 | Arduino wattmeter | Freddy | @Björn, For the voltage input you could try to make an differential input. You will have then two high impedance inputs (V- & V+). @Wolfram, you can post photo's here via an external link. See House Rules & Post Instructions . Unless there is an Arduino instruction or libary to convert time to a string, i'm afraid you have to write it yourself. You must give the time a new paramRange number, say 98 (this is vacant), and call your own function to write the time. |
| 15 apr 2016 12:42:07 | Arduino wattmeter | Wolfram Fischer | Hi Freddy, i have build this nice Powermeter into a nice case, put a LO/HI Autorange into the Software, it switches a 10MOhm Resistor with Relays and the Vdiv Value is switched too. That works very good! Is it possible, to show photos of it if i send you some? A question about the LCD-Calls (i dont understand them so good): if(paramRange[paramPo] == 100) { // int number lcdTechNot(0, timeCnt, paramRange[paramPo], paramDigits[paramPo], paramUnits[paramPo], ofm, pos, true); it shows the seconds.. so far so good. I have made counters for seconds, minutes, hours and days. time_s,time_m,time_h,time_d how can i show them in a format like this: "day-h-m-s" 3days 23:12:33 ? is it possible to put the time values into a string and send this to the LCD? Regards, Wolfram |
| 15 apr 2016 10:29:15 | Arduino wattmeter | Björn | Hi Freddy, Fully appreciate that you can't rewrite the code and that was not my intetention. I'm very happy with the hint. As I intend to use the unit on mains, I'm looking for ways to do that safe (apart from the standard precautions you mention). I found this component, ACS756SCA-100B-PBF-T, that will insulate the current input (both Ac and DC). However, I need to modify the input circitry slightly. Still have not found a simple way of insulating the voltage input. A transformer would work, but only for AC. Keep up the good work! |
| 14 apr 2016 21:09:27 | Arduino wattmeter | Freddy | I don't have time to write code for everyone's needs. You have to do it yourself. But I will give you a hint: In "void loop()" there is a section that calculates the three the cumulative values: Flux, Charge and Energy. You can make this small section conditional to start and stop the addings. |
| 14 apr 2016 16:31:54 | Arduino wattmeter | Björn | Hi Freddy, I'm very impressed of the functionallity of this meter. I'm not a very experienced programmer, but I've managed to convert the code to run on a UNO. I've also added other parameters (like load resistance) derived from the ones already provided . However, I would like to add two digital inputs, one that holds or preferably stop the totalising registers (energy, charge etc.) and a second that starts the totalising again. This would allow for pulse energy measurements. Another feature that could be useful is a timer that let's you do measurements in a time window. Do you think it's feasibly to add that into the code? Thanks for a great project! I've learnt loads. |