Time to get all our instruments recalibrated...

[lewis]

[coppercone2]

don't make thread titles like that someone is gonna fucking die

[Rerouter]

Voltage changes by 0.1 ppm, he isn't wrong,

Every bit of equipment using the old constant value is consistent with themselves, but not to the top standard,

[Mr. Scram]

don't make thread titles like that someone is gonna fucking die

Never the subtlest of responses, are they?

The thread title is fully correct. Of course, as both scales should be fully linear they should also be readily converted.

[coppercone2]

you gotta break it gently, the thread title makes you feel like your entire life was a lie

Maybe its good that I never went more then 6.5 digits. Watch them argue about plank in a few years. 

better to live in a haze?

What if some fundamental constant changes because of shady goverment experiments in like The Quiet Earth? What if planks constant is found to oscillate or something as time elapses or as our galaxy moves through the universe or some other weird reasons  ?

[wraper]

Voltage changes by 0.1 ppm, he isn't wrong

Frankly it's not that significant even for 8.5 digit multimeters. They still will be well in spec. For example Keysight 3458A:

Extraordinary accuracy
– 0.6 ppm for 24 hours in DC volts
...
– 8 ppm (4 ppm optional) per year voltage
reference stability

[Mr. Scram]

you gotta break it gently, the thread title makes you feel like your entire life was a lie

Maybe its good that I never went more then 6.5 digits. Watch them argue about plank in a few years. 

better to live in a haze?

What if some fundamental constant changes because of shady goverment experiments in like The Quiet Earth? What if planks constant is found to oscillate or something as time elapses or as our galaxy moves through the universe or some other weird reasons  ?

The new definitions have been a result of our improved understanding of the universe and its nature, so redefining things even better once more would be nothing new.

[Edwin G. Pettis]

I just had my SR-104 certified to 0.15 PPM uncertainty.....I'm not worried.  Voltage standard is next soon.

[technix]

I think all 34470A are likely have to go back and recalibrate. The lower end gear... Maybe not so much,

[wraper]

I think all 34470A are likely have to go back and recalibrate. The lower end gear... Maybe not so much,

Why would they if the change is even outside of the last digit of 24h accuracy spec?

24 hours TCAL ± 1 °C
10 V 0.0025 + 0.0004

0.1ppm = 0.00001%

[Henrik_V]

Watch the livestream
Witness a historic moment; join an open session of the General Conference on Weights and Measures (CGPM)
considering the revision of the SI – including redefinition of four of the base units

https://www.youtube.com/thebipm

NOW

[technix]

The vote is on.

[technix]

The vote is done, and the resolution passed unanimously. New SI effect May 20 next year.

[BrianHG]

[0culus]

So is there a straight source that actually lays out who is affected by this? Is it only really high precision equipment? Or is my life a lie? 

[Kleinstein]

The changes are so small, that only the highest precision instruments are effected. At 0.1 ppm change this might be just noticeable with a larger set of of well maintained 734 or similar references - so maybe the larger national labs, but not the usual instruments like 3458 or fluke 8508.

If in doubt one just keeps track the the old cal was still due to the old SI. So nothing to worry about.

[mycroft]

https://xkcd.com/2073/

[apis]

From what I understand: since the change is because of a redefined constant you don't need to re-calibrate, just re-adjust all instruments where it might matter. The troublesome part will potentially be trying to figure out if an old measurement you read about in the future is referring to the old volt (or ohm) or the new one if it matters. Takes effect 20 May 2019.

[grizewald]

https://xkcd.com/2073/

Death to Imperial measurements!

A gallon? WTF!

In the UK, 4.5 litres. In the USA, 3.8 litres!

If people can't even agree to have the same meaning for a shared unit; just give it up and go metric, please?

Also, most people don't have 12 fingers. 12 inches to the foot? 

Maybe we should specify the speed of light as 1.8026×10¹² furlongs per fortnight?  Or buy fuel in millihogsheads? 

[JoeO]

You are half a world away.  Why do you care?

[Mr. Scram]

You are half a world away.  Why do you care?

Yes, it's not as if data and technology gets shipped across the world at near light speeds.

[RoGeorge]

Better recalibrate. 
In Ancient Egypt, death was the penalty for uncompliant instruments, and they were recalibrating monthly, not like us!

Very good talk about metrology:

[001]

don`t worry about kilogram whilst holy pounds and gallons are ok

[fsr]

https://xkcd.com/2073/

If people can't even agree to have the same meaning for a shared unit; just give it up and go metric, please?

Seriously, using the same unit of measurement, scaled by multiples of 10 is so convenient!
I know that habits are difficult to change, but using inches, feets, yards, miles with some "random" conversion factor between them must be a pain in the ass.
Just imagine that instead of having kV, V, mV, uV you have 4 different units to measure the same thing, with different conversion factors between them. Not very convenient!!

[coppercone2]

it's already like that with digital readouts on some calipers. If you work in imperial you can get fractional readouts. I think its a complete mess when you start getting to 32nds and beyond.

Yea imagine your multimeter told you some shit like 3 and 5/16ths of a milivolt and 43/83's of a microvolt. 

I wonder when they will fix thermal units........