Re: [volt-nuts] 3458A NVRAM

[Dan Kemppainen]

FYI,

Ramtron was acquired by Cypress Semiconductor. I've had trouble finding 
some FRAM parts, but that may be changing as Cypress scales up production.


Also, watch out for fraudulent parts on ebay. I've ended up buying a 
couple things that were bad, although not ramtron parts.


Anyway, Keep us posted on the FRAM upgrade. I'm curious how it works out.

Dan




I'm looking at the A5 board in my 3458A.

The DS1220Y and the two DS1230Y NVRAMs have 1997 dates, so should likely be
replaced.  I *think* the Ramtron FM1608-120-P is a direct "drop-in"
replacement in this application for the DS1230Y.  Is that right?  If so I'll
get some in from eBay.

Is there an FRAM direct replacement for the DS1220Y-150? Or should I use a
FM16W08 on a 28 way SOIC to DIP adapter as per


Thanks
Dave


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Re: [volt-nuts] Update on 720A

[Dan Kemppainen]

On 8/9/2017 12:00 PM, volt-nuts-requ...@febo.com wrote:


I have trouble believing that the precision WW resistors
in the oil bath did go low.  I wouldn't presume to argue
that you didn't measure them right, but there has to be
something other than their value drifting low. WW
resistors usually go up and become erratic on their way
to becoming open circuit.



That's a great observation. What possible causes are there?

Contamination in the oil? (Water, other fluids)

Loose/shorted turn of the resistor wire?

Not much else that could make resistance drop. If the unit suffered 
physical or environmental abuse, these may be possible explanations.


Dan

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Re: [volt-nuts] PCB Artist

[Dan Kemppainen]

On 12/14/2016 7:18 AM, volt-nuts-requ...@febo.com wrote:

Our company has been committed to Eagle for about 5 years.  The problem
you face is that your investment in IP (schematics, board layouts,
component libraries, etc) vastly out-values the software.  With a
proprietary system, you're either locked in or face huge costs in
converting.

Indeed.  I am just about to pull the trigger on KiCAD company-wide.  I
think it is ready for the kind of work we do (4 layer boards, some with
high current/voltage traces).  The only thing holding me back IS our
investment in IP.  Maybe with Eagle 7 using XML for data storage,
someone will write an Eagle to KiCAD converter.

I strongly recommend learning KiCAD (a fairly daunting task) before you
get any significant amount of IP committed to a proprietary format.




John makes some good points. The cost of not only IP, but even the time 
to learn the software add up significantly. Storing data in proprietary 
formats can lead to trouble later. (Eagle's proprietary format is a bit 
less proprietary now that it's .xml!)


KiCAD vs. Eagle vs. PCB Artist, Pads, vs. (fill in the blank) really 
depends on what you need. If it's a one off board, with a handful of 
components anything should work. You can always redraw it later in 
something else. If you have 500 components, differential signals, and 
controlled impedance stuff that's a different story.


Let us know what you end up doing.

Dan

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Re: [volt-nuts] volt-nuts Digest, Vol 88, Issue 4

[Dan Kemppainen]

On 12/13/2016 12:00 PM, volt-nuts-requ...@febo.com wrote:

If you don't have any personal preference, then
KiCad is definitely the way to go. It has improved
dramatically since it got the CERN treatment and
doesn't cost a cent regardless of size and layers.



I haven't run PCBArtist, however it supports outputting Gerbers, which 
is nice. You are not tied to a particular board house.


I've sort of been forced to play with KiCAD for a project, and can't 
stand the user interface. I've been running eagle for a long time, that 
probably biases me towards that. Granted, eagle does have a sharp 
learning curve also, but KiCAD just hurts to use.


Keep in mind I'm referencing this to other CAD programs like AutoCAD, 
PTC Creo, ViaCAD and Eagle. KiCAD just feels clunky, even worse than 
LibreCAD.


This really is frustrating to me, because I really like the idea FOSS 
software, but lack of support and clunky UI make it hard to adopt for 
anything but one off hobby projects.


Anyway, my $.02. If anyone has any advise on how to get up to speed on 
KiCAD, I'd be interesting in hearing it!



Dan



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[volt-nuts] Meter...

[Dan Kemppainen]

Hi,

How much would you be asking for this?

Dan


On 10/31/2016 12:00 PM, volt-nuts-requ...@febo.com wrote:

Message: 3
Date: Mon, 31 Oct 2016 15:22:41 +0100
From: Andrea Baldoni <   >
To: volt-nuts@febo.com
Subject: [volt-nuts] FS: NOS Agilent 34401A
Message-ID: <20161031142241.ga27...@sol.ermione.com>
Content-Type: text/plain; charset=us-ascii

Hello.

Saturday I bought a 34401A. I was interested just in another instrument but
the seller insisted to sell them only together, so I had bought this one also.

The condition is very good, it has been sold to me as NOS but I cannot be sure.
However, I checked calibration number and it's 35, means it has only the
initial factory calibration, date April 11 2001. It's complete with rubber and
handle, it's clean, without any scratch, display is bright, and everything is
like you should expect from a, if not really NOS, lightly used instrument.

I would keep it, if I had not already other two of them in the same condition
in my lab, plus a switch unit with the same multimeter inside... so it will
not end on an auction site: I offer here to the group and if no one is
interested, I'll keep it.

It's a US made Agilent marked version, with red and black binding posts (not
the previous all red ones) but still square power button and rectangular shift
key, software revision "11/05/02". Original paper User's guide and Service
guide are included, as well as a power cord, CD with Intuilink software,
original test lead kit still in the bag. The calibration certificate with
test report is missing, and I don't have original box. All the rest of the
standard accessories are there.
Of course, calibration is absolutely expired. I have not enough equipment to
verify if it's still inside limits in every range; besides that it seems to
work correctly. Other questions, just ask.

Note: it's identical to the other two I have, except that they have initial
calibration two months earlier and serial some thousands lower.
I didn't upgrade their firmware (and I don't think user can do
it) thus the software revision date late than calibration is evidently
normal for this batch.

I can eventually ship everywhere but I prefer to ship inside EU.

You can send your (reasonable) offers via mail.

Best regards,
Andrea Baldoni


--

Subject: Digest Footer

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Re: [volt-nuts] volt-nuts Digest, Vol 83, Issue 6

[Dan Kemppainen]

On Sun, Jul 03, 2016 at 12:33:04PM +0200, Andrea Baldoni wrote:

Hello.
I repeated the experiment with a better setup, I also added
some alloys that are already arrived. So far, a really "low"
EMF solder hasn't been identified.



Measurements have been done between water ice point and boiling
point with Agilent 34401A. I don't expect the curves be linear,
but here it's assumed they are.



Copper - Sn96.5/Ag3/Cu0.5 -> 3.35uV/K
Copper - Sn95.5/Ag3.8/Cu0.7 -> 3.22uV/K
Copper - Sn60/Pb40 -> 3.34uV/K
Copper - Pb92.5/Sn5/Ag2.5 -> 3.02uV/K



Copper - Brass -> 3.30uV/K



I am waiting for Sn96/Ag4, Sn99/Cu1.


Any plans on testing Sn42/Bi57.6/Ag0.4 ?

Thanks,
Herbert



It would also be interesting to get SN100C in the mix if you can find it...

Dan

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Re: [volt-nuts] Building a high resolution DAC

[Dan Kemppainen]

Hi,

20 bits is ~1ppm resolution. 1ppm is pushing stability for most 
references, is it not? I would think that at 24bit or more the reference 
is more of an issue than the DAC itself. As I recall, sub PPM/C 
references already eat up your budget and then some! One would guess 
that as soon the fundamental question of how to build one is answered, 
the details would quickly stack up against you.


If the control loop is very slow (I'm making the assumption this would 
be used as oscillator steering EFC signal...), long term drift in the 
minutes to hours range would be important, and PPM/C becomes more 
critical than noise, as the higher frequency stuff could be filtered out.


A few PPM reference, some PPM resistors, circuit traces and 
temperature/humidity affecting the circuit board could add up VERY 
quickly.


Also, once I clear up a few projects here, I would be interested 
participating in such a project!



Dan




On 8/17/2015 10:29 AM, volt-nuts-requ...@febo.com wrote:

That's the next thing. But I will not worry about tempco until
the fundamental problem is solved:-)

Attila Kinali

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Re: [volt-nuts] *WAY* too expensive for even Keysight to, redesign

[Dan Kemppainen]

On 5/15/2015 12:00 PM, volt-nuts-requ...@febo.com wrote:

In this paradigm shift I think Keysight is better then most.


In my experience Agilent/Keysight has been very good. Had a signal 
generator long out of warranty, develop a problem with a front panel 
encoder. When calling for a replacement part they asked about why I 
needed the part...


To make a long story short I ended up sending the signal generator in 
for service work and new NIST calibration, all free of charge. For 
something 7 years out of warranty, I was very pleased. Been buying a lot 
of Agilent/Keysight since then.


Not saying one should expect this sort of service, but in at least one 
case they offered it!


Dan



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Re: [volt-nuts] Design Spark PCB Design Package

[Dan Kemppainen]

Have you looked at Kicad? It is used by both professionals and hobbyists,
and being open source, is not reliant on RS to update it.

Now there is a decent open source PCB layout program,  I would not suggest
anyone learn a new proprietary package unless there were very good
reasons,  such as an employer says you must use a particular program.



OK, I keep hearing how great KiCAD is, and should abandon everything 
else. I'm being persuaded to try KiCAD, and am not very impressed. If 
you do one board a year, it may be OK. But if you do a board or two a 
week, forget it.


When you create a board, you have to export the netlist from the 
schematic and import it into the board manually. No foreword/back 
annotation is maintained automatically.


Second, there is no way to highlight a net in the schematic, to show 
what pins/components are attached to it. Makes it very hard to follow 
what is actually connected.


However for me the killer is you have to map each schematic entity to 
the physical package for every board layout. When you make a library 
item, such as an opamp, the schematic symbol is not tied to the package. 
You have to map them in a separate step. Huge time consumer!


Libraries are also not solid yet. You are better off creating your own. 
Also, the package is bloated with a whole bunch of .pdf's for various 
chips. (Why???) Printing is a schematic is problematic, and seems to cut 
off the left edge of the page on my printer.


That said, I am following the project with interest, and would really 
like to see it turn into a full blown package. In some number of years, 
that should happen. However at this point I do not feel it is ready for 
daily use. It feels like beta software.


If you've actually used KiCAD and know something different, please speak up!

Dan



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Re: [volt-nuts] volt-nuts Digest, Vol 64, Issue 4

[Dan Kemppainen]

Hi,

We have the professional Eagle at work. I also own a pro copy at home. 
The learning curve is a bit steep, but we have done some pretty neat 
stuff with it. It's more than paid for itself at home and at work. It's 
not really a cheap cad package, but it's also not the high end cad. Sort 
of a middle of the road. Same sort of issues with CAD/CAM packages for 
CNC also.


As for auto routers, none of them really work all that well IMO. Even 
the high end cad packages struggle with it. It's really hard to do in an 
autorouter what a good RF or analog engineer does in his mind, so that's 
to be expected I guess.


As for upgrading, we also experienced upgrade issue going from Ver5 to 
Ver7. And from Ver3.5 to Ver4.16, and from 2 to...
This last upgrade from Ver5 to Ver7 we had trouble with 126 of about 
1000 schematic/board sets. About half of those were things guys had done 
stupid. However the XML format allowed editing of most of the files, and 
after about 2 days everything was upgraded successfully to ver7. So, 
yeah, pretty painful.


The one thing I will say about Eagle, is the few questions I've had were 
answered with a quick phone call. Not sure if KiCAD has phone support or 
not. In a business environment, that can be worth a lot.


When you do the new board with KiCAD, be sure to post some results to 
your induction list. I'd like to hear how it works out...


Dan




We have the Professional licenses.  As you say, the learning curve is
steep but once learned, I find myself surprisingly productive.  But the
autorouter is junk.  We bought one license but I never could get it
configured to do anything useful.

We have a LOT of IP tied up in Eagle's proprietary version 5 format.  We
upgraded to 6 and 7 but the conversion to the new XML splattered every
layout we threw at it so we demanded a refund and are still using V5.

The real catalyst for our move to KiCad was that after they'd collected
a bunch of upgrade fees, they announced that the new version would come
with copy protection.  The user base revolted and they backed down in a
little less than 6 weeks.  But lesson learned.

I'll keep a current unlicensed version installed so I can view what
others are doing but our involvement with Eagle is over.

I'm starting a new induction heater design next week using KiCAD.  I'll
occasionally report on how it's going.

John

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[volt-nuts] Voltage Reference.

[Dan Kemppainen]

Hi All,

I'm working on something that requires a stable voltage reference.
Long term stability isn't needed, but good thermal stability is. In
other words it would be nice to have sub ppm/C temperature, but a few
ppm/month or even per day isn't an issue.

Anyway, it got me thinking about building a reference for fun, with some
of the newer IC's available, but doing so in an ovenized housing.
I know the LM399's and LTZ1000's are out there, but has anyone looked at
any of the newer IC's out there?

For example this one seems to have pretty good ppm/C drift:
http://www.digikey.com/product-detail/en/VRE3025JS/598-1916-ND/2036526
However it's not cheap.

And this one looks pretty good for the sub $10 price.
http://www.digikey.com/product-detail/en/ADR4550BRZ/ADR4550BRZ-ND/3196874
This is the one I was thinking about parking in an oven. It has a
turnover around 70C.

Has anyone played with inexpensive reference chips, and tried to make a
good reference out of them? Any thoughts or comments welcome!

Dan






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Re: [volt-nuts] volt-nuts Digest, Vol 36, Issue 14

[Dan Kemppainen]

This one looks more complex than you describe.

However, I have one of the more simplified units, as you describe (At 
least, I think I do), which I would like to learn more about...


Dan



On 8/24/2012 8:00 AM, volt-nuts-requ...@febo.com wrote:

Its a potentiometer used to measure dc voltage.
A standard cell was used to set the total voltage across a series string
of resistors and a slide wire.
The dc voltage to be measured was balanced against the voltage developed
across a selected substring of resistors and the tap on a slide wire.
Lead acid batteries and similar cells were used as a source for the
slide wire and series resistor string current.
A galvanometer was used a s a null detector to determine when the
v0oltage across the slide wire and series resistor string were equal.
The resistors were typically immersed in mineral oil contained within a
copper tank below the ebonite (or similar ) faceplate.

Bruce



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