Bayite DC v-A-w meter (Jim Wilkins)

Jim - you have posted about your Bayite DC all-in-1 meter: (Amazon.com product link shortened)
Do you know if it measures true RMS, or does it measure average? My interest is mainly for full wave rectified AC, it is usually not a clean 1/2-wave sinusoid.
Thanks, Bob
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"Bob Engelhardt" wrote in message
Jim - you have posted about your Bayite DC all-in-1 meter: (Amazon.com product link shortened)
Do you know if it measures true RMS, or does it measure average? My interest is mainly for full wave rectified AC, it is usually not a clean 1/2-wave sinusoid.
Thanks, Bob
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I don't trust those things to read pure DC accurately or hold their calibration, and check them against a lab-grade 1.000 milliOhm shunt when it matters. I think as a rule the maker clearly tells you if a product can read RMS, otherwise assume it reads Average.
You might look into the UT-61E if you need accurate RMS readings for hobby use. (Amazon.com product link shortened)
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On 1/13/2021 3:06 PM, Jim Wilkins wrote:

You're right, of course. What maker is going to go to the trouble of including a desirable feature without mentioning it? They would boast of it.
That meter is so attractive for its function:price ratio that I couldn't help but hope that it was RMS.
Thanks, Bob
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"Bob Engelhardt" wrote in message
On 1/13/2021 3:06 PM, Jim Wilkins wrote:

You're right, of course. What maker is going to go to the trouble of including a desirable feature without mentioning it? They would boast of it.
That meter is so attractive for its function:price ratio that I couldn't help but hope that it was RMS.
Thanks, Bob
--------------------------
I checked the 100A AC version, PZEM-061, against a Kill-A-Watt with a refrigerator load and it matched the KAW's Watts display, so it reads RMS. The KAW's VA reading was substantially higher.
I haven't used the 100A DC meter very much because my battery application really needed a meter that shows + and - current. The 20A version is fine on pure DC test current until it wanders out of calibration, possibly due to the dawn and dusk fluctuations of solar panel voltage. On pulsed current in or out of a PWM or MPPT solar controller none of my meters agree.
The important questions are if a battery is fully charged and how long it will run my refrigerator, and unlike with Lithiums tracking the charge and discharge currents doesn't seem to answer that well enough, because other factors interact. The meters just show if things are or aren't working right.
The SIN9020S battery fuel gauge I'm testing now is "currently unavailable".
A 1" PVC conduit tee makes a good insulated housing for the 100A shunt.
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"Jim Wilkins" wrote in message
I checked the 100A AC version, PZEM-061, against a Kill-A-Watt with a refrigerator load and it matched the KAW's Watts display, so it reads RMS. The KAW's VA reading was substantially higher.
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Correction: it reads real power, not necessarily RMS.
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On 1/14/2021 10:56 AM, Jim Wilkins wrote: ...

It's winter, there's a pandemic, so you're stuck in the house and what you need to do is build the meter that does exactly what you need it to do. Can't be that hard? Just an Arduino and some code ... Bob's your uncle. <BG>
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"Bob Engelhardt" wrote in message
On 1/14/2021 10:56 AM, Jim Wilkins wrote: ...

It's winter, there's a pandemic, so you're stuck in the house and what you need to do is build the meter that does exactly what you need it to do. Can't be that hard? Just an Arduino and some code ... Bob's your uncle. <BG>
------------------------------ I would need better A/D sensitivity and resolution and NOT one common ground for what I'm doing. It's working pretty well right now with homebrew discrete analog power circuits and diode switching 'logic'. Unfortunately I haven't found inexpensive UL-rated substitutes for the modules I can build, but not sell.
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On 13/01/2021 20:06, Jim Wilkins wrote:

I've got the UT70B one that has RS232 output which has proved useful for some temperature data logging. I found some code online to unscramble the data output and incorporated it into some force/torque testing software I maintained at the time so I could analyse the data, it already handled RS232 input so just need a handler to decode the data from a new instrument. Found the receipt in the box and it's now 10 years old and still all good.
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"David Billington" wrote in message

I've got the UT70B one that has RS232 output which has proved useful for some temperature data logging. I found some code online to unscramble the data output and incorporated it into some force/torque testing software I maintained at the time so I could analyse the data, it already handled RS232 input so just need a handler to decode the data from a new instrument. Found the receipt in the box and it's now 10 years old and still all good.
---------------------------------------
I've written meter decoder code too, so I could switch off a battery discharge load at a low voltage threshold. This may be helpful: https://sigrok.org/
Meters that transmit their display segment patterns are easy to decode with a Select Case.
Otherwise I use the meters' programs and combine the separate .csv data files in a spreadsheet by aligning the time stamps.
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On 15/01/2021 19:14, Jim Wilkins wrote:


OK, I didn't know it was the segment pattern that was output, I just looked and found some code to decode it and it didn't explain the reason it was in that format. Maybe I'm spoiled as my Sylac digital DTI has RS232 output in human readable format.
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"David Billington" wrote in message ..... OK, I didn't know it was the segment pattern that was output, I just looked and found some code to decode it and it didn't explain the reason it was in that format. Maybe I'm spoiled as my Sylac digital DTI has RS232 output in human readable format.
----------------------------
What do you use to write hardware control programs?
I got into it when the engineers tasked me to create applications boards and programs for new ICs, that would run on a customer's unmodified lab computer. At the time the best solution seemed to be to use the printer port bits for the interface. In order to have full unhindered read and write access to the the port's I/O registers, which Windows and VB don't allow, we used QBasic under DOS, which has only the brief clock interrupt, otherwise my program had full control of everything except USB. QB provided a nice Integrated Development Environment with interpreted or compiled execution of the relatively small stand-alone applications programs that I was writing. The final DOS version of QBasic has the structured syntax of Pascal and C's pointers, great improvements on the original Basic.
The PIC was the preferred uC for small jobs so I've only played briefly with an Arduino. The choice for important tasks was the TMS320 DSP family. I've never had a chance to program one though I did design a DRAM controller IC for it.
However printer ports went away and USB replaced RS232, and my old laptop's batteries are dying, so I'd like to find an IDE with hardware register access capabilities to replace QBasic. The main reason for laptops is remote datalogging, I couldn't very well strap a desktop onto a prototype electric motorcycle or use one in a Cessna. At home I could be datalogging beside the basement water heater or out at the manually aimed solar panels.
The degreed technical staff kept the pure hardware design or programming tasks for themselves, but I was assigned the ones that required some competence in both, plus circuit board design and mechanical packaging which is critical at microwave frequencies like GPS.
Lab computers are former office computers, and AFAIK always ran Windows. I acquired some UNIX experience in the lab, though I'm far from fluent in it. Mitre used Macs, with LabVIEW for hardware control if the NuBus interface boards were available or I could build one.
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On 16/01/2021 15:25, Jim Wilkins wrote:

I'm only programming stuff for myself these days as I retired from Windows programming back in mid 2011 after 20 years doing it. My favourite language would be C followed by C++, I have also done 68000 assembler which I quite like and understand but hate Intel assembler. I have some Arduinos to play with and that is basically C from what I've seen so far so get along with that well and having written code for 16bit Windows and Blackberry keeping state information I'm used to. I've only briefly used PICs for some smartcard coding and some serial comms. I'm back now to my origins in mechanical engineering.
Having started in Windows 3 the access to hardware was unrestricted so have made the obligatory parallel port A2D. I've been using Linux for my personal computing since about 1999 but haven't needed to do any low level access but the ioctl function is provided for that and can be used with the parallel port, the equivalent in Windows would be DeviceIoControl , I've not used it but it's provided in Win32 SDK. I can remember the days back in the 1990s when it was necessary to thumb through the Win16 API book to find a function to do something, might only have taken an hour or 2 but quite useful as I remembered a lot of functions which were useful later.
The first software company I was employed at had 3 guys that had electrical and electronic engineering degrees but when something needed doing I got asked to look at it as I had the most practical digital and analogue electronic experience and I was a MechEng. One of them summed it up saying that he could design a transistor from scratch but didn't know what to do with it. Regarding limited IO on PCs I got asked once to make a watchdog for a PC based telemetry system using Windows 3.11 which locked up occasionally, not really a surprise, and ended up using the speaker drive as an output to reset the watchdog, it only needed a single MessageBeep () added to the source code and recompiling the sytem in those days took only about 10-15 minutes.
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On Saturday, January 16, 2021 at 10:25:45 AM UTC-5, Jim Wilkins wrote:

I wouldn't limit Cessna to such a description.
At home I could be datalogging beside the

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"bruce bowser" wrote in message
... The main reason for laptops is remote

I wouldn't limit Cessna to such a description.
----------------------
The engineers did that part of the testing so I don't know which planes they flew in. I just built the hardware.
https://www.faa.gov/about/office_org/headquarters_offices/ang/offices/tc/about/campus/faa_host/labs/csi_team/ftb/eng_services/
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On Saturday, January 23, 2021 at 8:52:59 PM UTC-5, Jim Wilkins wrote:

Oh, sorry. I just don't know where a laptop ends and a desktop begins... which is smaller... which has more durable power circuitry, etc...
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"bruce bowser" wrote in message ... Oh, sorry. I just don't know where a laptop ends and a desktop begins... which is smaller... which has more durable power circuitry, etc... ------------------------------------------------------
Our 1990's lab machines were all business-class former office computers, large desktops or very portable laptops, not oddball home computers like the tiny old iCue or the later large and heavy desktop replacement laptops with HDTV screens. For me a useful laptop needs a decent battery life and an auto-air (12V) power adapter, a keyboard you can type a report on and a screen big enough to read a .pdf.
I did some development work on a 4" square PC/104 computer that would Velcro to a monitor or a TV until management cancelled it.
The largest "portable" computer I was involved with filled 6 Army trailer trucks. They tested its portability by setting up where only deer could find it.
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On Wed, 13 Jan 2021 08:39:11 -0500, Bob Engelhardt

For sure it will be average, but the reading will be jiggered upward by 11.1% to match RMS on a sine wave.
(11.1% is 2*sqrt(2)/pi)
Best regards, Spehro Pefhany
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