Re: non-profit engineering
On 4/11/20 12:51 PM, Tam Hanna wrote: Nah, no hard feelings man. But it is unbelievable for Americans that, in
Austria and Germany, you can go to jail 10 years simply for saying things. It's almost that bad here nowadays, but the results are less "out in the open". Say the wrong thing and your contracts start to dry up, your construction permits stop getting issued, little things like that. They make it hard to forget who's in control, if you're not a "sheeple" type. But yeah, that's pretty scary stuff over there. But I'd never recommend moving here. An average rapist or murderer does less, by the way. :-( -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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On 4/11/20 12:50 PM, Tam Hanna wrote: typing this on a Linux box: for instrument control, go Windows or go bust. BS. I've done instrument control for 2.5 decades, with great success and wanting for nothing, and I have never run Windows. Adding an extra layer of madness which is LinuxGPIB on top of already
flaky GPIB implementations in most test kit is not something you want to
do. If that's the way you want to do it, be my guest, but I've never used LinuxGPIB either. As for the software: I gave, somewhere, a printed cal manual for the
4195A as mine was sold to a research institute in the UDSSR originally.
I would be surprised if it does not hold the source code for the apps. I
can go and dig, if you so desire. That would be very handy if the source is included. The idea would be to create a functional clone, of course, but reading the sources would make short work of that. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: non-profit engineering
Nah, no hard feelings man. But it is unbelievable for Americans that, in Austria and Germany, you can go to jail 10 years simply for saying things.
An average rapist or murderer does less, by the way.
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 11. 18:50, Dave McGuire wrote: On 4/11/20 12:48 PM, Tam Hanna wrote:
nah, this was NOT funny. Oops. That was not my intention, my apologies.
I risked arrest due to her cussing about a strange malady which hits
some people and hit a mutual acquaintance of ours whom we, due to fate,
do not like too much. First it affects the mind, and then it has all
kinds of damages. And we were musing about how AIDS, Cancer and all we
would maybe have celebrated, but this is a bit much for the poor guy. Ouch. :-(
As for why Dorit is an ex: that is a? loooong story, and I already
procrastrinate too much. I know the feeling. ;)
-Dave
|
Hi,
typing this on a Linux box: for instrument control, go Windows or go bust.
Adding an extra layer of madness which is LinuxGPIB on top of already flaky GPIB implementations in most test kit is not something you want to do.
As for the software: I gave, somewhere, a printed cal manual for the 4195A as mine was sold to a research institute in the UDSSR originally. I would be surprised if it does not hold the source code for the apps. I can go and dig, if you so desire.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 11. 18:40, Dave McGuire wrote: On 4/11/20 12:32 PM, Tam Hanna wrote:
No Windows. Seriously man, life is too short for that garbage. But
thanks for the effort.
But either way, we're discussing getting the existing software
running, not general means to access instruments via HPIB. The eventual
goal would be to port the existing software out of RMB and to something
generalized and maintainable (and, forgive me, but moving from one
proprietary language to another is probably not the best idea) and more
accessible. But we must first access, and probably run, the original
software. A lot of it is not available in source form, so we'll
probably end up sniffing HPIB traffic to figure out what it does.
-Dave
|
Re: non-profit engineering
On 4/11/20 12:48 PM, Tam Hanna wrote: nah, this was NOT funny. Oops. That was not my intention, my apologies. I risked arrest due to her cussing about a strange malady which hits
some people and hit a mutual acquaintance of ours whom we, due to fate,
do not like too much. First it affects the mind, and then it has all
kinds of damages. And we were musing about how AIDS, Cancer and all we
would maybe have celebrated, but this is a bit much for the poor guy. Ouch. :-( As for why Dorit is an ex: that is a? loooong story, and I already
procrastrinate too much. I know the feeling. ;) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: non-profit engineering
Hello,
nah, this was NOT funny.
I risked arrest due to her cussing about a strange malady which hits some people and hit a mutual acquaintance of ours whom we, due to fate, do not like too much. First it affects the mind, and then it has all kinds of damages. And we were musing about how AIDS, Cancer and all we would maybe have celebrated, but this is a bit much for the poor guy.
As for why Dorit is an ex: that is a? loooong story, and I already procrastrinate too much.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 11. 18:42, Dave McGuire wrote: ROFL wow!
Trust me on that one. My ex-wife was in Government. Is that why she's an "ex"? ;)
-Dave
|
Re: non-profit engineering
On 4/11/20 12:35 PM, Tam Hanna wrote: you seriously need to come to Austria if you want to see real government
corruption. Well, yeah, but everyone says that about their country. My "adoptive kid" from the conservative fashion company always complains
about how the Liberals are out of control in her state. Then, I was on
the phone with her from Western Europe, and had to take her off
speakerphone...after that happened, she takes a more positive view of
the USA. ROFL wow! Trust me on that one. My ex-wife was in Government. Is that why she's an "ex"? ;) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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On 4/11/20 12:32 PM, Tam Hanna wrote: a tornado? You mean the aircraft or the wind thing which turns rapidly?
Either way, I wish you good success in cleaning up. The wind kind. Thanks. We are ok, but there was some building damage and a couple of days without power. Some friends are coming out to help pull some troublesome latticework off of the front of the museum building; it partially broke loose during the storm on Tuesday night. Bleach didn't work; I had to throw that underwear away. It was days ago and we are still a bit rattled here. As for the topic
nazis: usually, I have seen these at the Scopes r Us mailing list. Here,
not so much.? But you, being owner, probably get more flak than I do. I'm just a moderator, not the owner, but yes, every so often one of these people who lack either a hobby or a delete key pops up. Admittedly the problem is much less severe here than on other mailing lists. As for RMB: I would use Visual Basic and a NI GPIB card. Works out of
the box. Here is an example, which should be easy to follow albeit it is
in Csharp: No Windows. Seriously man, life is too short for that garbage. But thanks for the effort. But either way, we're discussing getting the existing software running, not general means to access instruments via HPIB. The eventual goal would be to port the existing software out of RMB and to something generalized and maintainable (and, forgive me, but moving from one proprietary language to another is probably not the best idea) and more accessible. But we must first access, and probably run, the original software. A lot of it is not available in source form, so we'll probably end up sniffing HPIB traffic to figure out what it does. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: non-profit engineering
Hello,
you seriously need to come to Austria if you want to see real government corruption.
My "adoptive kid" from the conservative fashion company always complains about how the Liberals are out of control in her state. Then, I was on the phone with her from Western Europe, and had to take her off speakerphone...after that happened, she takes a more positive view of the USA.
Trust me on that one. My ex-wife was in Government.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 11. 18:29, Dave McGuire wrote: Yeah, well:
- They're my customers, not me, and I have no control of where (or
if) they take their business. This situation has stopped the gravy
train well before it gets to my stop.
- Most of my work comes from startup companies. In this country,
inventive people are conditioned very hard to believe that they cannot
start a company without "investors" (which is, and always has been, BS),
and investor money inevitably comes with lots of strings attached,
including highly detailed reporting requirements.
- It's the aforementioned investors that have put the kibosh on most
of it. A brilliant kid with a Solution goes to an investor for funding,
who now responds with something like "Nope, now you've no way to get it
manufactured, so go piss up a rope."
- This is not Europe. The US Gov't is perhaps the most effective,
efficient money-taking organization the world has ever seen. Just TRY
to keep one red cent from them, in any context. It doesn't work. The
only thing this country protects more than the pampered asses of the
lying, thieving suits in Washington DC are its revenue streams.
So, yeah. Nice idea, but in this reality it just doesn't work.
-Dave
On 4/11/20 12:10 PM, Tam Hanna wrote:
Cry me a river. In Europe, we have worked under - and circumvented -
customs for like 40 years. There is a lot you can do to "reduce" the
value of the shit being shipped. Many things are totally legal, even.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy
Electronics Lab at
On 2020. 04. 11. 3:11, Dave McGuire wrote:
On 4/10/20 9:06 PM, John Griessen wrote:
On 4/10/20 7:07 PM, Dave McGuire wrote:
??? Well that's for the museum, not for my company, but yes.
??? Anymore, in this society, if I'm walking down the street and pass a
guy wearing a tie, I check to see if I still have my wallet. I'm thinking of doing a 501-c for everything I do...
What big profit was I making as sole proprietor anyway? ?? Ahhh.? Well that would be pretty tough for me to get away with; I run
it as a company and this is how I feed myself and my family.
?? Though the way things have been since Der Trumpf's damn tariffs, it
may as well be registered as a "non profit".? I can design stuff for
people, but now nobody has any cost-effective way to get it
manufactured!? This has stopped the Pittsburgh tech startup scene (my
core business) in its tracks.
????????????? -Dave
|
Hello,
a tornado? You mean the aircraft or the wind thing which turns rapidly? Either way, I wish you good success in cleaning up. As for the topic nazis: usually, I have seen these at the Scopes r Us mailing list. Here, not so much.? But you, being owner, probably get more flak than I do.
As for RMB: I would use Visual Basic and a NI GPIB card. Works out of the box. Here is an example, which should be easy to follow albeit it is in Csharp:
?using NationalInstruments.NI4882;
using System;
. . .
namespace VGPIB1
{
??? public partial class MainWindow : Window
??? {
??????? private NationalInstruments.NI4882.Board myBoard;
??????? private NationalInstruments.NI4882.Device my6624A;
??????? private NationalInstruments.NI4882.Device mySolartron7150;
??????? private void LogQuine(String _a)
??????? {
??????????? TxtLogField.Text = TxtLogField.Text + "\n" + _a;
??????? }
??????? public MainWindow()
??????? {
??????????? InitializeComponent();
??????????? try
??????????? {
??????????????? myBoard = new NationalInstruments.NI4882.Board(0); //hoffe es ist 0
??????????????? LogQuine("GPIB-Board bereit!");
??????????? }
??????????? catch (NationalInstruments.NI4882.GpibException e)
??????????? {
??????????????? LogQuine("FEHLER: GPIB-Treiber unwillig bzw besch?ftigt!");
??????????? }
??????????? catch (System.InvalidOperationException e)
??????????? {
??????????????? LogQuine("FEHLER: GPIB-Boardnummer falsch!");
??????????? }
??????????? mySolartron7150 = new Device(0, 12);
??????????? mySolartron7150.Write("M0R3I0N1T1\n"); //Vdc 20V tay numeric triggerself
??????????? my6624A = new Device(0, 5);
??????????? float limiter;
??????????? for (limiter = 0; limiter < 40; limiter+=1.00f) {
??????????????? String gpibString = limiter.ToString();
??????????????? gpibString=gpibString.Replace(",", ".");
??????????????? my6624A.Write("VSET 4," + gpibString + ";\n");
??????????????? my6624A.Write("ISET 4,0.2;\n");
??????????????? Thread.Sleep(20);
??????????????? gpibString = mySolartron7150.ReadString(80);
??????????????? String[] myRawDataArray=gpibString.Split('\n');
??????????????? double[] myResults = new double[myRawDataArray.Length - 2];
??????????????? for (int i = 1; i < myRawDataArray.Length - 1; i++) {
??????????????????? myRawDataArray[i] = myRawDataArray[i].Replace("00.", "0,");
??????????????????? myRawDataArray[i] = myRawDataArray[i].Replace(".", ",");
??????????????????? myResults[i - 1] = Convert.ToDouble(myRawDataArray[i]);
??????????????? }
??????????????? double myAverage=0;
??????????????? for (int i = 0; i < myResults.Length; i++)
??????????????? {
??????????????????? myAverage += myResults[i];
??????????????? }
??????????????? myAverage /= myResults.Length;
??????????????? LogQuine(limiter.ToString().Replace(",", ".") + "," + myAverage.ToString().Replace(",", "."));
??????????? }
??????? }
??????? private void CmdWriteOut_Click(object sender, RoutedEventArgs e)
??????? {
??????????? System.IO.StreamWriter file = new System.IO.StreamWriter("C:\\Users\\TAMHAN\\Desktop\\VISA-1\\diagram.csv");
??????????? file.WriteLine(TxtLogField.Text);
??????????? file.Close();
??????? }
??? }
}
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 11. 18:26, Dave McGuire wrote: On 4/11/20 11:50 AM, Tam Hanna wrote:
Yeah, thats the spirit. Take it all off line, so that the next dude who
stumbles across a 4195A can resume operations by scratching his balls. Well first of all, any self-respecting man is going to do that anyway,
realistically.
I am willing to help out, to try and source stuff from the Western
German, to do measurements on my own 4195A, anything. But PLEASE, let us
keep it online on the list.
People can, and do, die, thereby making their knowledge unavailable. I,
for one, am pretty close - domestic warfare, as my adoptive kid calls
it, is starting to wear me down. Despite all the money I've paid to hit men trying to eradicate them,
there are still a few topic nazis on this list. I say this wearing my
"one of the moderators of this mailing list" hat.
Now that's not to say the topic of getting HP computers set up to run
HP software to work on HP test equipment is anything but 100% kosher
squarely on-topic here...it is. But there are a number of old farts
(even older than you and I!) among us who seem to cling to the erroneous
belief that everyone here is a hobbyist playing in their garage, and
therefore obviously excludes anything that might need computer
assistance to calibrate.
So yes, keep such discussions here. Getting HP-9000s set up properly
to run the software in question is not always easy, and many of us would
benefit from having such discussions live on in the list archives.
I'm off to spend the rest of the day cleaning up tornado damage at the
museum. Maybe when I'll come back, installing RMB on an HP-9000 will be
a solved (and archived!) problem. =)
-Dave
|
Re: non-profit engineering
Yeah, well:
- They're my customers, not me, and I have no control of where (or
if) they take their business. This situation has stopped the gravy
train well before it gets to my stop.
- Most of my work comes from startup companies. In this country,
inventive people are conditioned very hard to believe that they cannot
start a company without "investors" (which is, and always has been, BS),
and investor money inevitably comes with lots of strings attached,
including highly detailed reporting requirements.
- It's the aforementioned investors that have put the kibosh on most
of it. A brilliant kid with a Solution goes to an investor for funding,
who now responds with something like "Nope, now you've no way to get it
manufactured, so go piss up a rope."
- This is not Europe. The US Gov't is perhaps the most effective,
efficient money-taking organization the world has ever seen. Just TRY
to keep one red cent from them, in any context. It doesn't work. The
only thing this country protects more than the pampered asses of the
lying, thieving suits in Washington DC are its revenue streams.
So, yeah. Nice idea, but in this reality it just doesn't work.
-Dave
toggle quoted message
Show quoted text
On 4/11/20 12:10 PM, Tam Hanna wrote: Cry me a river. In Europe, we have worked under - and circumvented -
customs for like 40 years. There is a lot you can do to "reduce" the
value of the shit being shipped. Many things are totally legal, even.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy
Electronics Lab at
On 2020. 04. 11. 3:11, Dave McGuire wrote:
On 4/10/20 9:06 PM, John Griessen wrote:
On 4/10/20 7:07 PM, Dave McGuire wrote:
??? Well that's for the museum, not for my company, but yes.
??? Anymore, in this society, if I'm walking down the street and pass a
guy wearing a tie, I check to see if I still have my wallet. I'm thinking of doing a 501-c for everything I do...
What big profit was I making as sole proprietor anyway? ?? Ahhh.? Well that would be pretty tough for me to get away with; I run
it as a company and this is how I feed myself and my family.
?? Though the way things have been since Der Trumpf's damn tariffs, it
may as well be registered as a "non profit".? I can design stuff for
people, but now nobody has any cost-effective way to get it
manufactured!? This has stopped the Pittsburgh tech startup scene (my
core business) in its tracks.
????????????? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
|
On 4/11/20 11:50 AM, Tam Hanna wrote: Yeah, thats the spirit. Take it all off line, so that the next dude who
stumbles across a 4195A can resume operations by scratching his balls. Well first of all, any self-respecting man is going to do that anyway, realistically. I am willing to help out, to try and source stuff from the Western
German, to do measurements on my own 4195A, anything. But PLEASE, let us
keep it online on the list.
People can, and do, die, thereby making their knowledge unavailable. I,
for one, am pretty close - domestic warfare, as my adoptive kid calls
it, is starting to wear me down. Despite all the money I've paid to hit men trying to eradicate them, there are still a few topic nazis on this list. I say this wearing my "one of the moderators of this mailing list" hat. Now that's not to say the topic of getting HP computers set up to run HP software to work on HP test equipment is anything but 100% kosher squarely on-topic here...it is. But there are a number of old farts (even older than you and I!) among us who seem to cling to the erroneous belief that everyone here is a hobbyist playing in their garage, and therefore obviously excludes anything that might need computer assistance to calibrate. So yes, keep such discussions here. Getting HP-9000s set up properly to run the software in question is not always easy, and many of us would benefit from having such discussions live on in the list archives. I'm off to spend the rest of the day cleaning up tornado damage at the museum. Maybe when I'll come back, installing RMB on an HP-9000 will be a solved (and archived!) problem. =) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: non-profit engineering
Cry me a river. In Europe, we have worked under - and circumvented - customs for like 40 years. There is a lot you can do to "reduce" the value of the shit being shipped. Many things are totally legal, even.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 11. 3:11, Dave McGuire wrote: On 4/10/20 9:06 PM, John Griessen wrote:
On 4/10/20 7:07 PM, Dave McGuire wrote:
?? Well that's for the museum, not for my company, but yes.
?? Anymore, in this society, if I'm walking down the street and pass a
guy wearing a tie, I check to see if I still have my wallet. I'm thinking of doing a 501-c for everything I do...
What big profit was I making as sole proprietor anyway? Ahhh. Well that would be pretty tough for me to get away with; I run
it as a company and this is how I feed myself and my family.
Though the way things have been since Der Trumpf's damn tariffs, it
may as well be registered as a "non profit". I can design stuff for
people, but now nobody has any cost-effective way to get it
manufactured! This has stopped the Pittsburgh tech startup scene (my
core business) in its tracks.
-Dave
|
Yeah, thats the spirit. Take it all off line, so that the next dude who stumbles across a 4195A can resume operations by scratching his balls.
I am willing to help out, to try and source stuff from the Western German, to do measurements on my own 4195A, anything. But PLEASE, let us keep it online on the list.
People can, and do, die, thereby making their knowledge unavailable. I, for one, am pretty close - domestic warfare, as my adoptive kid calls it, is starting to wear me down.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 10. 22:47, Bruce wrote: Be happy to help - lets talk off line.? I have a working 900/300
system with HPIB, basic and HP UX, needing only a color monitor (have
the B/G monitor).
Do you have a favorite imaging software?? I've been using a program
called Omniflop - seems to archive just about any format I've run into.
Anyway, contact me off line for more discussion.
Cheers!
Bruce K9BC
bruce@...
H
Quoting Dave McGuire <mcguire@...>:
Yup, definitely interested.? It's a lot of stuff and I'm spread a bit
too thin.
??????? -Dave
On 4/10/20 3:53 PM, Bruce wrote:
Put me on the list to notify as you get to them.? I could help if you
are interested in help.
Cheers!
Quoting Dave McGuire <mcguire@...>:
On 4/10/20 3:16 PM, Bruce wrote:
I'd like to correspond off line about how you did the translation.? I'd
like to do the same for the 8340 and some other equipment I have.? As I
said, I have an 9000/300 system and a good hpib analyzer to work with.
I'd be interested in any insight you have developed in the process of
translating the software.? I'd be willing to share any of the HP softwar
I've collected ? On that note, I have calibration and verification software for many,
many different instruments that I got from a calibration house that shut
down.? It will be awhile before I will be able to image the disks and
tapes, but that is my eventual plan.? They are safe for now.
????????????? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Re: Racks for older equipment
Costco also sells them. Bakers Racks. I bought a dozen of them a
couple of years ago to set up gear in my garage. They were 79.00 on
sale. I did find that a dozen of these is about the limit for a Chevy
S10 longbed pickup.
Sam Reaves
ARS W3OHM
Owner and Moderator of:
LeCroy Owners Group on Groups.io (Current and Future Group)
Electronics and Mechanical Hardware Design Engineering Manager
Andritz Rolls Global Research Center (RETIRED)
|
Re: Seeking advice on a precision DVM
FWIW I have a Fluke 8842A. It reads down to .001 ohms. 5v on the probe tips.
|
Hello,
I have a friend that is looking for the schematics of the power supply of its HP70004 in high quality. He has some files but they are not readable.
Someone could help us to find that document ?
Thank you,
Best regards,
Fabien, F4CTZ.
|
Re: Racks for older equipment
LOL at the Jean Stapleton (AKA Edith Bunker) "Those Were the Daaaaays" memories!
Jim Ford?
Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message -------- From: Dave McGuire <mcguire@...> Date: 4/10/20 7:47 PM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] Racks for older equipment
On 4/10/20 10:43 PM, bownes wrote: > When working for a small CLEC that became a good sized one (where I > became acquainted with the good Dave McGuire) we used to put a microwave > data endpoint, a T1 modem, a router and a switch in a rock n roll road > case and ship it to places we wanted to do temporary internet drops. It > survived a few years including a trip to Woodstock 25th reunion.? ? <Jean Stapleton voice> ? Those were the days! ? </Jean Stapleton voice> ?????? -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: Seeking advice on a precision DVM
On 2020-04-10, at 22:05, victor smith <vcs3@...> wrote:
And actually price/performance might lead you to the hp 3457, they are ridiculously cheap.
(Full disclosure: I just got three more :-) But they are full rack size units, like the 3456 also. And bench space is important, to me! Well, the 3457A are rack width (425mm (16.75 ¡°)), but only 292mm (11.5 ¡°) deep (compare to 3456A at 527.1 mm (20? triple-barleycorns)). Compared to a 3456A (10.49 kg (23.13 lbs)), they are also very light (5.05 kg (11.1 lbs)), so they can be lugged easily to the place they are needed. The robust plastic case and the low weight also mean that it¡¯s a bit harder to damage them while lugging them around. Disadvantage: the 3457A input resistance is 10G¦¸ only up to 3 volts, while the 3456a can do 12 volts at that input resistance. But then, in Ohms, 10 ?¦¸ resolution, where the 3456A is 100 ?¦¸. The 3457A can output up to 12 V in Ohms ranges, enough to fry many MOSFETs (so hello Harbor Freight(*) for that!), while the 3456A is slightly friendlier to your circuits at 9.5 V max. And so on. And don¡¯t forget the 3457A are 3030000 counts [6.48 digits], so they have more than one bit more of resolution than the 1200000 counts [6.08 digits] of the 3456a. I still love the 3456A display, though¡ Only the Keithley 192/196 are even more beautiful. [Well, OK, Datron 10xx can¡¯t be beat, but those are not LED.] Gr¨¹?e, Carsten (*) OK, ANENG. And those are incredibly accurate for what they are¡
|
Re: Seeking advice on a precision DVM
I have 2 HP3456's, picked up in the San Diego area for $20 and for $50. I like the fact that it is calibrated with multi-turn pots accessible from the front panel, rather than calibration constants stored in a battery backed up memory. Long out of cal and my DIY LM399 10 Volt source also long out, but checked recently against an average of 3 out of cal meters, so I'm eagerly waiting my turn for access the the EEV floating cal standard.
<>
Hope COVID19 doesn't break the chain.
I've bought a pair of Aneng AN870 4 1/2 handheld multimeters and found them to be within spec, much better than a Harbor Freight meter.
David, contact me privately and perhaps I can get some 0.01% resistors to you to check your ohmmeter. KK6IL@...
John
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On 4/9/2020 10:28 AM, Daniel Koller via groups.io wrote: Hi All,
? I am wondering what sort of DVM the collective wisdom here might suggest for precision work.
? I am working on a project for work that involves designing a precision voltage controlled current source.? But due to the current pandemic, I am working from home and assembling and testing stuff in my own well equipped basement shop.? ?The current source is more or less a design out of Horowitz and Hill's "The Art of Electronics".? ?I am working to keep the full scale and linearity of this current source to within 0.1% or better.
? My current best DVM is a Keithley model 173 DMM "4 and 1/2" digit, 4-wire meter (the leading digit reads to 3).? It's accurate to ~0.009%+1 digit over 24 hours on the V scales and ~0.035%+1 digit on the Ohms scales.? ?I think it's good enough for what I need, but it has a few limitations, and I am wondering if it is not time to upgrade to a real bench instrument.
? ?First of all, my DVM probably hasn't been calibrated in decades.
?How do I know it's correct without some externally calibrated transfer standard?? ?It *may* be a possibility for me to use a meter at work (sent regularly to calibration services) and calibrate a portable voltage reference and bring it home.? ?But I don't have a resistance standard.
? The other problem is that even with 4 wires on the lowest Ohms setting, I don't have enough resolution to measure a 0.100 Ohm sense resistor to within 1%.
? ?So, I think I could use a better meter.? ?The HP34401A DVM seems like a nice meter to have.? It's even used as a circuit design example in H&H's text.? But they seem to go for several hundreds of $$ on e-bay.? ?Remember, this is coming out of my hobby budget.
? So, I looked at the? HP3455A / 3456A on e-bay.? These seem to be significantly cheaper, and I love vintage instruments.? BUT, do I want to take up a new project?? How reliable are these old beasts?? Are they easy to repair and calibrate?? ?What tends to go wrong with them?
? ?Even though it's more expensive, one major strong point of the HP34401A is in addition to GPIB, it's got a SERIAL interface on the back!? That is a whole different ballgame in terms of interfacing to a PC or laptop (and a whole lot easier for me, for sure).? But I do think I want to have a meter I can use, rather than one I will have to repair.
? Are there any other models I am missing?? ?Are there any that come standard with an RS232 interface?? Please let me know and thank you in advance for your suggestions.
? Dan
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Dave McGuire
Sam Reaves