USA Cal Club: Round 2

[bitseeker]

"Inch by inch, life's a cinch. Yard by yard, life's hard." — John Bytheway

Life has its ups and downs. Just work on those inches and you'll get there. Good to see you back on the forum, CM!

[Svgeesus]

Got the ref boxed up and mailed to Svgeesus today!   

I'm sorry this took so long.

I'm also sorry. I got this last night, when I arrived back at my house. (I had planned to be back 8 days earlier, but life intervened).

Unpacked, all looks good, now re-reading this thread before powering it up.

Note that the reference is better than the LM399 in my (in cal)  Keysight 34465A, so I am really testing my meter not the reference.

[Svgeesus]

I uploaded this to the xdevs ftp server, directory svgeesus:

Code: [Select]

Operator: Chris Lilley (svgeesus)
Date: 10 Nov 2018
DUT: US Cal Club 2 PX reference
Type 1b: Direct measurement, calibrated equipment (in 1 year spec or better)
DMM: Keysight 34465A, instrument ID 869657
Cal date: 28 Nov 2017
Cal type: Accredited 17025 with uncertainties
Cal temp: 23.0C
Cal humidity: 23.0% RH
Cal procedure: 34460-90901 Truevolt DMM service manual, July 2016 edition 3
Cal inst: Fluke 5725A amplifier, ID 06-0090, NIST 12678290, Cal date 03 Aug 2017
Cal inst: Fluke 5700A/EP03 calibrator, ID 21-0140, NIST 11901768, Cal date 01 Dec 2016
Cal inst: Agilent/HP 33250A function generator, ID 407410002, NIST 12901089, Cal date 13 Oct 2017
Cal front panel zero offset, short, 10V range: as left 0.00000, min -0.00002V max 0.00002V, uncertainty 5.8uV
Cal front panel +10V, 10V range: as left 9.99999V, min 9.99966V max 10.00034V, uncertainty 35uV
Measurement details: front panel, 100PLC, HiZ
PX2 mean: 7.0456366V
PX2 lowest: 7.04563V
PX2 highest: 7.04564V
PX2 samples: 562
PX2 sd: 1uV
PX2 corrected: 7.045643V
ambient: 22.0C 33% RH (arduino, free air) 22.5 (k-type, above ref)
power: 11.94688V from supplied voltage regulator, fed with 15.0V from Tenma 72-8335A linear bench PSU

Equipment:
- Keysight 34465A dmm, instrument ID 869657
- Tenma 72-8335A linear bench PSU
- DM6801A temperature meter, K-type probe
- Cal club Arduino temp/humidity sensor
- Ian Johnston PDVS2 voltage source

Vreg was fed with 15.0V from Tenma 72-8335A linear bench PSU.
Output measured on Keysight 34465A, front jacks, 100PLC

Time series plot from cold shows that the regulator reached a stable voltage fairly rapidly.

Once warmed up (100PLC, HiZ, front jacks, T=21.7C, RH=32%:

Code: [Select]

mean 11.94688
lowest 11.94665
highest 11.94721
sd 115uV
ambient 21.7C

Next measured the reference, from room temperature, powered by the vreg, 100PLC, HiZ, front jacks.

I'm now considering using my Ian Johnston PDVS2 set to 7.0456V in opposition to the PX ref and measuring the difference. Note that the PX ref is more stable and less noisy than the LM399 in both the PDVS2 and the 34465A.

Once it was stable, measured the stability for 30 minutes.

[Svgeesus]

Used my Ian Johnston PDVS2 set to 7.0456V, in opposition to the PX ref and measured the difference. Note that the PX ref is more stable and less noisy than the LM399 in both the PDVS2 and the 34465A. So really, this is more a stability measurement on the PDVS2.

Result: mean -69.5μV min -75.3 max -61.1 sd 2.4μV, n=1493.

Package posted back on Weds 14th, expected delivery Mon 19th.

[dr.diesel]

I don't recall the exact order, but please skip over me till spring.

[hwj-d]

  ... ... what??
(edit: that's me)

Hi Jason,
pm send. 

Many greetings,
and relaxing holidays to all. 

[cellularmitosis]

... ... what??
(edit: that's me)

Haha, sorry my friend    I had asked for hwj-d's mailing address, but he was "asleep" for a little while.  Then, after not hearing from him, on literally the same morning that I decided to skip over him and mail the ref to Vacuumminded instead, he replied with his mailing address    Don't worry, you're next in line! 

I took a bit of data before mailing the ref out to Vacuumminded.  It was a bit noisy, so I added a Savitsky-Golay filter (thanks again to Mr. Hoffman for the tip):

https://github.com/cellularmitosis/logs/tree/master/20181219-k2015-cal-club

Edit: I had discovered that by the end of my data, my lithium ion battery had dropped below the minimum input voltage of the 15V regulator, so the supply was no longer in regulation.  That might explain the dip at the end.

Edit2: the x scale is just shy of 24 hours (wed 11pm to thu 10pm).

Edit3: And here's the order of the queue: https://www.eevblog.com/forum/metrology/usa-cal-club-round-2/msg1680698/#msg1680698

[Vacuuminded]

Much to my surprise, I received the package TODAY!     Will be spending some time to go back over what has been done this round, and get the logging squared away.  I did quickly shuffle things around and fire up the ref itself, and everything appears to be fine so far   Letting the meters cook, they've been off for a few months. 

[vindoline]

Excellent!  Glad to see some action on this project and thread. CM, isn't TiN prepping another reference for our club? Do you have any status update on that?

[TiN]

vindoline

CM, isn't TiN prepping another reference for our club? Do you have any status update on that?

Yep, there is "FX" 10V LTZ1000A-based reference for USA Club in cooking, it's on since October, and still need bit more time before final calibration test and shipping out.
I'll do my best to get it delivered in January'19. Sorry it's taking so long, LTZ references don't like haste. 

[hwj-d]

TiN,
take a nap, meanwhile 

[vindoline]

vindoline

CM, isn't TiN prepping another reference for our club? Do you have any status update on that?

Yep, there is "FX" 10V LTZ1000A-based reference for USA Club in cooking, it's on since October, and still need bit more time before final calibration test and shipping out.
I'll do my best to get it delivered in January'19. Sorry it's taking so long, LTZ references don't like haste. 

Thank you TiN. You're generosity is humbling. 

[kj7e]

vindoline

CM, isn't TiN prepping another reference for our club? Do you have any status update on that?

Yep, there is "FX" 10V LTZ1000A-based reference for USA Club in cooking, it's on since October, and still need bit more time before final calibration test and shipping out.
I'll do my best to get it delivered in January'19. Sorry it's taking so long, LTZ references don't like haste. 

Just tossing this out there, I would be willing to take some measurements and compare the "FX" to my references (recently calibrated at CalMachine's lab).  Up to you and Jason.

[Vacuuminded]

Happy New Year, cal club members! 

I've been struggling with trying to get the temp/humidity logging working with the included Arduino Uno, has anybody else with a Windows machine successfully used Jason's script, as found below?  Using Python via Windows command prompt the script seemingly runs, (I am presented with a blinking curser and no ability to enter further commands), however no "log.csv" file is being generated. 
https://gist.github.com/cellularmitosis/a509a6470c068fd0746a7c7b49bd9a90

Likewise running the below script to simply write serial data to the console, it gets no further than line 19 stating that "typeError: write() arguement must be in str, not bytes"
https://github.com/cellularmitosis/logs/blob/master/plotting-scripts/trivial-serial.py
If I change line 19 from "sys.stdout.write" to "sys.stdout.buffer.write" (as suggested on a python forum for a similar issue) the error no longer pops up, but again all that is presented is a flashing curser which cannot accept any further text/commands. 

I am _not_ a code guy and after many hours of frustration only to get this far, am about to give up on the logging so that we can keep this thing moving.  Serial data can be seen from the Uno via the actual Arduino program, so I don't think it is an issue with my system-  Just my understanding of what I, or these scripts are doing wrong! 

Regards,
Chris

[vindoline]

Perhaps you could send Cellularmtosis a PM and ask for help? He used to be very active on the forum, but he seems to have other things going on lately.

I'm afraid I can't help, as I'm not a "code guy" either. Also, I use a Mac and Raspberry Pi for my logging solution. It took me a long time and a lot of tortured hack coding to get it working. I started with the Python scripts the Muxr posted a long time ago. Good luck

[cellularmitosis]

Yeah, we tried to get it debugged over email, but I’m out of town at the moment and don’t have a windows machine handy

I’m not sure what to make of the error about binary data.

[bitseeker]

I haven't seen/used the latest logging setup, but since it's Python, is the version of Python that's installed compatible with the code? I've seen some programs only work correctly with a particular Python version.

[Vacuuminded]

Ha, I just happened to think the same thing yesterday afternoon, and am waiting Jason's reply to an email.  I just assumed everyone is using Python 3 instead of Python 2, since it was released over a decade ago.  I'm not familiar enough to identify any difference via the code itself, so I'll certainly try downloading 2 and see what happens if nothing further is known before then. 

[bitseeker]

Yeah, 3.x has been around for a long time, but a surprising amount of code still requires 2.x. I don't know the versions well enough to point out anything that would specifically cause the problem you're running into, but it was the first thing that came to mind. Hopefully, that takes care of it.

[Vacuuminded]

Just a quick update, the script is currently running via Python 2.7.xx.  this was the main problem    Will try to wrap this up as quickly as possible and git 'er back to Jason! 

[bitseeker]

Thanks for the update, Vac. Glad that was it.

[ArthurDent]

It will be quite a while before my name comes up but I have recovered from my disaster back in June, 2018, where I accidentally destroyed my first LTZ1000 by forgetting to disconnect the power before making some wiring changes. My new reference looks good as far as I can tell with the HP3457A I have. The battery supply and charger are built into the case I'm using. No switches were used and just A.C. in, red/green bi-color LED for charging/charged and live indication, 2 sets of gold banana jacks on the front panel for both 7 and 10 volts, and 30 turn pot. Batteries feed the reference through a 12 volt regulator and will keep it powered for over 36 hours.

Everything is a compromise and I felt this was good enough for my first go around. After I use it for a while I may make some changes to the next one. I have another case and identical metal box for version II. Here's a couple of photos of the reference.

[TiN]

 
I hope you have air baffle over LTZ chip on both sides.

[ArthurDent]

Even have a foam washer around legs on front side and flat foam square on back side between board and thin fiberglass insulation sheet under entire board.

[vindoline]

Nice construction! Where did you source the steel box from?