If you interested in transferring precision DC volt into your home-lab suitable to test even 6½-digit DMM, now it’s possible for owners of KX LTZ1000 voltage reference module. Detailed build and example of such implementation also well explained here.

Calibration offer for members with xDevs.com KX LTZ1000 PCB

After discussion on EEVBlog forum, member mimmus78 decided to jump in and order my Gerber files for LTZ1000A module, as I had already sent all extra ones long time ago.

He got PCB fab to manufacture 20pcs and decided to send all but 3 boards to other metrology enthusiast at the cost.

Image 37-38: KX LTZ1000 PCBs received by mimmus78

And there is some healthy number of people willing to try their own build using these boards:

I did not really expect such following of this little project, so decided to provide bit of support in return, to encourage such project involvement.

Support boils down to free (almost, you still cover shipping) calibration service of any xDevs.com KX voltage reference module using these LTZ1000 PCBs.

To make things simple, here are the “rules”.

STEP 1. Build your KX-module, publish short worklog in this thread (few photos of assembled PCBA, photo of it running with DMM hooked up showing 7V)
STEP 2. Leave it running for 200 hours, so initial drifts get stabilized. Module should be enclosed in some box without vents.
STEP 3. Measure it again, record the temperature and voltage and put a label with values on the box
STEP 4. Ship the box to me (USA). You pay shipping.
STEP 5. I’ll power your box with +15V for 48 hours to have everything stabilize
STEP 6. Test 7V output voltage in temperature span +20….+30C, record the graph
STEP 7. Unit will be shipped back via EMS Express (~30-40$USD, 4-7 days to USA, bit more to EU). You pay shipping.

All steps are mandatory, to make sure that reference is good and stable, otherwise it would be no much point in ppm-level calibration, if initial aging drifts are not removed first.

This is standing offer, without schedule or specific date deadlines, unless my homelab changes or other force majeure events occur.

Even though I don’t have official calibration performed on my equipment, thanks to volt-nut community and multiple cross-checks I’m confident that my DCV accuracy is around ±2 ppm.
And to make this even better, few other EEVBlog members also backed up this initiative to provide same calibration offer in their regions.

Thumbs up for the members! I’d be happy to publish these folks builds test results and photos of their home setup, perhaps in next upcoming “fairy-tale” article!

Current participants

• EEVBlog member VK5RC with 1 x KX-LTZ module. Using Edwin’s PWW resistors and shipped assembled with LDO regulator. Under drift test now. Shipment back target: 7 May 2017.
  Completed, Calibration Report – assigned value +7.134057 VDC, July 17, 2017.

• EEVBlog member CalMachine with 1 x KX-LTZ module.
  Completed, Calibration Data – assigned value +7.141467 VDC, December 14, 2017.

• EEVBlog member CalMachine with 1 x KX-LTZ module.
  Completed, Calibration Data – assigned value +7.157411 VDC, December 14, 2017.