Ongoing Development

The new documentation was a grind, and took a lot longer than I had anticipated (what doesn’t?). But it’s on the air now and Although I have some pressing topics to add, I would call the conversion done.

So moving on, there are two things in development:

The rollout of version 4.9 of the hardware, along with the new enclosure, is still taking up some time, and will continue to do so until about mid-March.

The next big project, which is planned out and somewhat started, is to build a new phase calibrator that can do 50Hz and 60Hz and hopefully test to 200A. Once that’s done, the job will be to retest all of the sample CTs in the collection and update the tables with both 50Hz and 60Hz shift corrections.

The last part of the job will be to change IoTaWatt to use the appropriate shift corrections for the measured line frequency.

One major hurdle that I’ve already passed is development of a new phase measurement algorithm for IoTaWatt. This new code produces very repeatable results to about 0.02°, so I’m optimistic that this will improve phase correction in the 50Hz world where the 60Hz calibrations are being used.

As I’ve said before, in the general case the net shift is usually reasonably close anyway, but there are some cases, particularly with the newer low shift VTs, where frequency specific calibrations can improve the results.


Hi @overeasy, I’ve just bought the board (waiting for it to arrive in Australia), assuming I’m going to get v4.8 of board? Where do I see the changes for 4.9?


The main improvem3nt from my perspective is the new enclosure, which will be produced from a custom mold, thus r3ducing cost a lot over the old stock enclosure that had to be machined in Japan. While designing the new enclosure, I took the opportunity to integrate the direct-reference three-phase adapter into the circuit board. That is the only significant change.

This won’t be available until second quarter 2019.

Otherwise, the 4.8 units will support all of the ongoing firmware changes. Your 4.8 unit has been shipped and should arrive soon.

Great. Thanks for your reply. I have 3 phase and my current plan is to try the derived mode. If I decide to go with real mode I might upgrade the board…

Appreciate your work

I’m using derived 3 phase in AU and am seeing almost no error.
all three phases are usually within 1v of each other, and obviously phase angle is also very close, so I’m pretty lucky I suppose.