Author Topic: USA calibration club (Read 152494 times)

cellularmitosis · « **Reply #500 on:** December 19, 2017, 09:22:40 pm »

lars, thanks for your reply. Do you happen to still have a copy of the circuit schematic which you designed? The original is currently returning a 404.

Andreas · « **Reply #501 on:** December 21, 2017, 05:26:24 am »

Hello,

I still have a copy from Lars.

with best regards

Andreas

CraigD73 · « **Reply #502 on:** January 28, 2018, 11:45:59 pm »

I recently acquired an HP34401A, appears to be fully functional and in perfect condition but was last calibrated in 97. Definitely interested in locating others in the SF bay area that have calibration sources to compare with. Currently gathering parts to build up an LTZ1000A which will also need calibration.

Really sort of new to this level of accuracy, just hope its a mild case.

Craig

cellularmitosis · « **Reply #503 on:** January 29, 2018, 12:46:35 am »

Welcome, Craig! We will restart the USA Cal Club soon with an upgraded reference

bitseeker · « **Reply #504 on:** January 29, 2018, 02:08:44 am »

Welcome, Craig, to both the forum and the cal club. Things like this always start out mild. Then, who knows...

CraigD73 · « **Reply #505 on:** January 29, 2018, 10:24:38 pm »

Thanks guys, winter is my work in the lab time been itching to do a project or two.

Finally figured out how to make the HP34401 Talk RS232, was driving me nuts till I figured out it needs a line feed at the end of the line and Putty sends a CR.

What are you guys using to plot the readings, I have Excel 2003 but there has to be some open source plotting app that is better?

Craig

cellularmitosis · « **Reply #506 on:** January 29, 2018, 10:50:01 pm »

I either use a modified version of a script which one of our users posted (Muxr), or I use google sheets if I need to manipulate the data first and it is something small and quick.

https://github.com/cellularmitosis/logs/tree/master/plotting-scripts

The nice thing about the 34401A is that you can put it into “talk only” mode, where it just broadcasts every measurement automatically. I wish every meter did that by default.

kj7e · « **Reply #507 on:** January 31, 2018, 04:14:10 am »

Im ready, networked in all my gear (that has LAN). 2x LTZ1000A references running, freshly cal'ed 34465A, new DMM7510, HP 3456A, HP 3457A, HP 3478A and a Keithley 191 since the last round (stupid eBay).

The HP 3457A with a cal date of 2000 still seems to be in spec!

The HP 3456A with a cal date of 1990 also still seems to be in spec!

cellularmitosis · « **Reply #508 on:** January 31, 2018, 02:41:46 pm »

Nice collection!

technogeeky · « **Reply #509 on:** January 31, 2018, 03:51:03 pm »

I would commit several small-level crimes to have a DMM7510 on my bench.

bitseeker · « **Reply #510 on:** January 31, 2018, 06:34:36 pm »

Quote from: kj7e on January 31, 2018, 04:14:10 am

Im ready, networked in all my gear (that has LAN). 2x LTZ1000A references running, freshly cal'ed 34465A, new DMM7510, HP 3456A, HP 3457A, HP 3478A and a Keithley 191 since the last round (stupid eBay).

Yeah, I think it's safe to say that you're good and ready! Nice collection!

Quote from: technogeeky on January 31, 2018, 03:51:03 pm

I would commit several small-level crimes to have a DMM7510 on my bench.

Just a hint of TEA?

RandallMcRee · « **Reply #511 on:** February 07, 2018, 03:28:30 am »

BTW

Put myself down for a new DMMCheckPlus from VoltageStandard.com (as discussed in this thread:
https://www.eevblog.com/forum/testgear/group-buy-proposal-voltagestandard-dmmcheck-plus/

Would be nice to send it around if that is of interest to the group.

Thanks,
Randy

CatalinaWOW · « **Reply #512 on:** February 07, 2018, 04:44:38 am »

Thanks for the update. Other members note that this offer is likely to be the last chance to buy a DMM Check. It has been discontinued once. Don't know how long the door will remain open, but the signs say just a few weeks or so.

nikonoid · « **Reply #513 on:** February 07, 2018, 06:30:59 am »

I have DMMCheck Plus that I got 3 years ago and have not adjusted it since. I like it a lot. If you are getting one, I highly recommend getting it with the enclosure. It is very good and functional and goes long way to keeping your unit safe and protected.

I fired mine up 30 minutes ago and having a specified tempco of about -3ppm/C, it is only 2ppm too low according to my calibrated Keithley 2002, when I apply temperature correction. It now fluctuates by about 1ppm up and down as the temperature is cycling.

I consider this quite awesome for a low cost reference. I would like to +1 the recommendation.

Sent from my iPhone using Tapatalk

bitseeker · « **Reply #514 on:** February 07, 2018, 07:10:55 am »

Looks like no more pre-orders until March.

kj7e · « **Reply #515 on:** February 07, 2018, 04:44:35 pm »

I had a DMMCheckPlus but sold it, since and regretted it.

cellularmitosis · « **Reply #516 on:** February 07, 2018, 06:12:17 pm »

I just remembered I bought a PentaRef from him about 3 years ago. At the time, I didn't really have the ability to try and characterize its drift or tempco. Might be time to dig it back up!

I think he will also give it a spot-check for like $20 -- might be worth throwing it in a temperature regulated box and using that as a poor-man's voltage transfer (as a cheap sanity-check against a "real" calibration service). If he maintains a 3458A in calibration, it might be worthwhile!

bitseeker · « **Reply #517 on:** February 07, 2018, 06:16:58 pm »

I hadn't seen why the DMMCheck models were discontinued. Was it lack of demand, to focus on voltage references exclusively, or something else?

kj7e · « **Reply #518 on:** February 07, 2018, 06:19:11 pm »

Doug cited costs at one point. Just not very profitable in the end.

bitseeker · « **Reply #519 on:** February 07, 2018, 06:23:21 pm »

Ah, I see. That makes sense as there is a lot to them.

CatalinaWOW · « **Reply #520 on:** February 07, 2018, 07:55:23 pm »

Quote from: bitseeker on February 07, 2018, 07:10:55 am

Looks like no more pre-orders until March.

I successfully put in an order just before I made my last post here. Must have made it just under the wire.

It is also worth double checking to see if the web site put you off. By searching for the DMMCheck it brings you that product page, which can then be entered into the shopping cart.

Off on a tangent, I wonder if the various people who have attempted to enter in this business have investigated the elasticity of demand for this product. The total market is clearly small, but perhaps it is not much smaller at 150% or even 200% of the current prices. This gets even further from the BOM costs which apparently drive somes folks attitude towards pricing, but there is surely a significant fraction of the market for these things that understands that not all of the value is in the BOM.

bitseeker · « **Reply #521 on:** February 07, 2018, 09:20:10 pm »

I think you made it just before orders got suspended. Hopefully, I interpreted it correctly. Here's the current message:

Quote from: voltagestandard.com

For the time being we have stopped accepting DMMCheck Plus orders but will start accepting them again in March, closer to when we will be shipping product.

Maybe they didn't want the backlog to get too big. Anyway, March isn't that far away.

RandallMcRee · « **Reply #522 on:** February 16, 2018, 03:58:32 pm »

Seems like I won an auction for 10 VRE3050 voltage references. I want two. The rest are available to club members for what I paid plus shipping.
https://www.ebay.com/itm/132499240091

Let me know.

Randy

vindoline · « **Reply #523 on:** February 16, 2018, 11:27:27 pm »

Quote from: RandallMcRee on February 16, 2018, 03:58:32 pm

Seems like I won an auction for 10 VRE3050 voltage references. I want two. The rest are available to club members for what I paid plus shipping.
https://www.ebay.com/itm/132499240091

Let me know.

Randy

Randy, I'm game for two.

bitseeker · « **Reply #524 on:** February 16, 2018, 11:48:03 pm »

Are you guys making transfer standards with these or something else?


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Author Topic: USA calibration club (Read 152494 times)

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