Jim - you have posted about your Bayite DC all-in-1 meter:
https://www.amazon.com/bayite-6-5-10...dp/B013PKYILS/

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

"Bob Engelhardt" wrote in message ...

Jim - you have posted about your Bayite DC all-in-1 meter:
https://www.amazon.com/bayite-6-5-10...dp/B013PKYILS/

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

--------------------------------------

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.
https://www.amazon.com/UNI-T-Digital...06XSYZZBV?th=1

On 1/13/2021 3:06 PM, Jim Wilkins wrote:
[snip] I think as a rule the maker clearly tells you if a
product can read RMS, otherwise assume it reads Average.
...
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 functionrice ratio that I couldn't
help but hope that it was RMS.

Thanks, Bob

"Bob Engelhardt" wrote in message ...

On 1/13/2021 3:06 PM, Jim Wilkins wrote:
[snip] I think as a rule the maker clearly tells you if a
product can read RMS, otherwise assume it reads Average.
...
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 functionrice 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.

"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.

-------------------------

Correction: it reads real power, not necessarily RMS.

On 1/14/2021 10:56 AM, Jim Wilkins wrote:
....
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.
...

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

"Bob Engelhardt" wrote in message ...

On 1/14/2021 10:56 AM, Jim Wilkins wrote:
....
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.
...

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.

On 13/01/2021 20:06, Jim Wilkins wrote:
"Bob Engelhardt"Â* wrote in message ...

Jim - you have posted about your Bayite DC all-in-1 meter:
https://www.amazon.com/bayite-6-5-10...dp/B013PKYILS/


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

--------------------------------------

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.
https://www.amazon.com/UNI-T-Digital...06XSYZZBV?th=1



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.

"David Billington" wrote in message ...

On 13/01/2021 20:06, Jim Wilkins wrote:
"Bob Engelhardt" wrote in message ...

Jim - you have posted about your Bayite DC all-in-1 meter:
https://www.amazon.com/bayite-6-5-10...dp/B013PKYILS/

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

--------------------------------------

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.
https://www.amazon.com/UNI-T-Digital...06XSYZZBV?th=1


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.

On 15/01/2021 19:14, Jim Wilkins wrote:
"David Billington"Â* wrote in message ...

On 13/01/2021 20:06, Jim Wilkins wrote:
"Bob Engelhardt"Â* wrote in message ...

Jim - you have posted about your Bayite DC all-in-1 meter:
https://www.amazon.com/bayite-6-5-10...dp/B013PKYILS/


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

--------------------------------------

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.
https://www.amazon.com/UNI-T-Digital...06XSYZZBV?th=1



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.


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.

"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.

On Wed, 13 Jan 2021 08:39:11 -0500, Bob Engelhardt
wrote:

Jim - you have posted about your Bayite DC all-in-1 meter:
https://www.amazon.com/bayite-6-5-10...dp/B013PKYILS/

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

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