MOD54415 Projects.

[Vernon]

Got a lot done today. The video (link below) shows calibration of the MOD54415 board power quality function vs, the Keithley lab standard. The board reads about 0.02% THD high at ~0.10% THD and about 0.03 low at 12.17%. I used a diode resistor network to create distortion in the signal applied to the meter and the circuit board. I am going to make that adjustable so I can check cal at several points. This is without any tweaks - just the raw algorithm results. In the interest of full disclosure note that Cooley and Tukey get credit for the algorithm - not me. See Wikipedia link below.

https://www.youtube.com/watch?v=62W628NGnnU

https://en.wikipedia.org/wiki/Cooley%E2 ... _algorithm

[Vernon]

Added buttons to toggle between the vector display and power quality FFT modes. It will also be able to record (on a flash drive) the highest voltage, the lowest voltage, and the highest THD for each 15 minute interval.

[Vernon]

Netburner in an ammo can? I note that enclosures seem oddly sized and overpriced - so I am starting the Netburner MOD54415 in an Ammo Can Movement. I am going to put this meter in one, you just open the lid and there is the front panel with the display and so on - but you could also install relays for your lawn sprinklers and so forth, punch holes for conduit bushings, and mount it on the garage wall. There are a lot of applications, it is waterproof with the lid closed, and you can get one for $10.

Robotics? Just put wheels on the bottom and lidar on top!

[Vernon]

This may not look particularly exciting but, in the name of efficiency, I created a new AC signal algorithm that is an FFT (Fast Fourier Transform) modified to produce a raw angle of the fundamental as well as the amplitude of the fundamental. The difference between the angles of two channels give one the phase angle - for a phase angle and amplitude meter. While I obviously have a function for that knowing the harmonic content, while combining the two functions is always nice and increases speed. This will run on the 250 MHZ MOD54415 measurement board processor faster than the original ran on the existing 16MHZ HS12. The picture is of the function running on the PC compiled in DEV C++. Waiting for a part for the Epoch so I can get it working. I need an input to run it on the actual board of course. Here the function is stepping through a long sine table (fake A/D data) and starting at increasing degree positions.

In other news I got the ammo can and it looks like it will be an awesome enclosure for the board. And the price is right. Don't want to pay $25 for some cheap little box.

[Vernon]

In one cycle!

I got the part for the Epoch 10 test source and finally tested my FFT based algorithm that, within one cycle, gets the voltage, the current, the phase angle and the harmonics thru the 7th for both the voltage and current. In the pictures the results appear in the right column of the screen with the results of the existing algorithm on the left. On the web screen shot the Vernon FFT results are below the existing method.

[Vernon]

Some pictures of the latest screens. In the picture where V2 (second harmonic voltage) reads 119+ I set the test source to output the second harmonic.

[Vernon]

Pictures of distortion calibration test vs the Keithley meter. I use a diode network with a potentiometer to introduce (mostly second harmonic) distortion and compare to the Keithley. Works great - very accurate voltage, current, phase angle, Watts, Vars and now - THD percent and harmonic voltages and currents for both the voltage and current channel.

[Vernon]

And - since it is so damn accurate I added a Watt Hour feature! The bottom picture shows the updated web browser screen shot - it now has all the harmonics and I added the WH section on the bottom. That gives you current UTC time and the reset time of the watt hour meter. The top picture shows performance of the watthour function. My MOD54415 board reads 105.6665 watthours and the Scientific Columbus standard (this is the good shit in energy meter standards) reads 176.467 revolutions. Since the Kh of the standard is 0.6 that computes at 105.880. Error is therefore 0.2% and that is not bad as I have not really calibrated the current - just set it to the Epoch 10 (and they are always a little off). One of these set up for permanent home use could double check the power company meter, give you harmonic distortion in the supplied voltage - and a running total toward your next bill! Note that I turned the current off in these pictures to stop the WH tally.

[Vernon]

The Ammo Can Meter!

Pictures show progress in installing the MOD54415 based AC meter in a surplus ammo can. Open the lid and you will see the front panel shown (I have to add an Ethernet connector but I am waiting for the 1 foot Ethernet extension to get here so I can measure it). Other pics show the size of the bare circuit board in the bottom of the can. Would also be great for any control project as it is easy enough to install conduit bushings - and it is much cheaper than a Hoffman box.

Don't know if anyone will buy an ammo can meter but I like it.

[Vernon]

I should have been an artist! Just kidding but I think my start up screen for the Ammo Can Meter looks pretty good. You have your transmission line tower set against a full moon and a black out screen. The meter will give you complete power system and harmonic metrics (see previous posts). I will probably paint the ammo cans flat black primer.