Electronics > Metrology

NEW PDVS2mini DC Voltage Reference from Ian Johnston - Reviewed.

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TheDefpom:
Hi All,
I thought I would pop this here, I just published a review of a new piece of equipment from Ian Johnston, the PDVS2mini, which is a 0-10V DC voltage reference.

No doubt you will spot things I am doing wrong, I'm not a metrology guy after all, but hopefully the video demonstrates the capabilities of the unit.

IanJ:
Hi all,

Working on a couple of software bugs at the moment, mostly down to the math.h library which isn't great on these small AVR's (it can't add or subtract properly!). So, having to write (C++) around the issue which is a pain.
Scott's low end non-linearity problem I don't experience on my own PDSV2mini's here.......so some detective work is required.

Prototyping Happy days!

Ian.

Svgeesus:
So, the Integral Non-Linearity is higher than the PSVS2, but because resolution is also higher it is compensated for in software?

branadic:
Scott, your meter also has INL which is not zero. You could use your F343 and make differential measurements to get more into that.

-branadic-

IanJ:

--- Quote from: Svgeesus on August 28, 2019, 04:07:39 pm ---So, the Integral Non-Linearity is higher than the PSVS2, but because resolution is also higher it is compensated for in software?

--- End quote ---

PDVS2 (18-bit DAC9881) INL = +/-2 LSB typical, +/- 3 LSB max.
PDVS2mini (20-bit MAX5719A) INL = +/- 1 LSB typical, +/- 20 LSB max.

The +/- 20 LSB is scary (when volt-nutting) so there is 11 y=mx+c calib setpoints between 0 and 10Vdc output (1Vdc apart).......to compensate/help minimize any deviation.

An alternative solution would have been to add in an ADC (low INL) and monitor the DAC output and compensate accordingly, but that just pushes the BOM/complexity up..........

Ian.

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