Topics

What is the meaning of ULU? Topic was: 7000-series power-hungry plug-ins

 

On behalf of all of us thank you Håkan once again.

Of course I know what Fold Back Current Limiting is. In its simplest terms it is a circuit that prevents you from burning up a valuable instrument while you are tinkering around inside it with a screwdriver or other metal tool. One of Murphy Law's guarantees that the more careful you are, the more catastrophic the damage you will cause. Fold back Current Limiting is designed to sacrifice active devices such as transistors and ICs in order to protect the fast blow fuse from stress.

"tinkera123" also asked what the acronym ULU meant. I was hoping someone would explain it. The specific sentence it is used in doesn't give much to go on:
"Some suggestions for the wiring interface to the ULU are offered."
This is followed by 5 suggestions.

From the suggestions it sounds like they are talking about a Device Under Test but the well-known acronym for this is DUT. Some companies use Unit Under Test or UUT.

So far no one has offered an explanation for ULU. I can't think of anything that fits those letters and there are very few ULU acronyms.

The closest I could up with is Unit Under Load which might mean a set of standard load resistors attached to a male connector that plugs into the backplane and loads the power supply enough to draw the maximum amount of power from each supply that the slot should be able to supply. But a Unit Under Load would be UUL. As anyone who plays Scrabble knows, the order of the letters can be really important.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
tinkera123
Sent: Friday, October 12, 2018 3:34 PM
Subject: Re: [TekScopes] 7000-series power-hungry plug-ins

Regarding this pdf of 7000 series currents ..... I am unfamiliar with the
terms Foldback currents and ULU.
Can some-one please explain??

-Chuck Harris

PS, thanks to Håkan for the 7904 power supply capacity note.


--
Dennis Tillman W7PF
TekScopes Moderator

Renée
 

I love the definition of "Fold Back Current Limiting " ...Dennis you are so right, the fuse always survives...LMAO....thanks I needed that...
Renée, K6FSB

On 2018-10-13 05:49 PM, Dennis Tillman W7PF wrote:
On behalf of all of us thank you Håkan once again.

Of course I know what Fold Back Current Limiting is. In its simplest terms it is a circuit that prevents you from burning up a valuable instrument while you are tinkering around inside it with a screwdriver or other metal tool. One of Murphy Law's guarantees that the more careful you are, the more catastrophic the damage you will cause. Fold back Current Limiting is designed to sacrifice active devices such as transistors and ICs in order to protect the fast blow fuse from stress.

"tinkera123" also asked what the acronym ULU meant. I was hoping someone would explain it. The specific sentence it is used in doesn't give much to go on:
"Some suggestions for the wiring interface to the ULU are offered."
This is followed by 5 suggestions.

From the suggestions it sounds like they are talking about a Device Under Test but the well-known acronym for this is DUT. Some companies use Unit Under Test or UUT.
So far no one has offered an explanation for ULU. I can't think of anything that fits those letters and there are very few ULU acronyms.

The closest I could up with is Unit Under Load which might mean a set of standard load resistors attached to a male connector that plugs into the backplane and loads the power supply enough to draw the maximum amount of power from each supply that the slot should be able to supply. But a Unit Under Load would be UUL. As anyone who plays Scrabble knows, the order of the letters can be really important.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
tinkera123
Sent: Friday, October 12, 2018 3:34 PM
Subject: Re: [TekScopes] 7000-series power-hungry plug-ins

Regarding this pdf of 7000 series currents ..... I am unfamiliar with the
terms Foldback currents and ULU.
Can some-one please explain??

-Chuck Harris

PS, thanks to Håkan for the 7904 power supply capacity note.

Harvey White
 

On Sat, 13 Oct 2018 19:32:21 -0700, you wrote:

I love the definition of "Fold Back Current Limiting " ...Dennis you are
so right, the fuse always survives...LMAO....thanks I needed that...
Renée, K6FSB
What happens in a technical sense is that the circuit is set up with a
(much lower) short circuit current limit. When the overcurrent
happens, the circuit "folds back" to the point where the maximum
current is the foldback limit. To get it to reset, you generally turn
power off and reapply power.

There's a particular setup in the uA723 regulator (yeah, old
nomenclature) that is available for that.

An example would be that you have a 5 volt supply at 1.5 amps,
foldback to 300 ma.

Voltage is reduced, of course, to maintain that maximum current.

The old data sheets for the UA723 would show that circuit. A nice
thing is that these regulators show up in Tektronix equipment.

and I *think* that a suitable quote runs something like this:

Fuse: an inexpensive part designed to fail to protect a circuit; is
always protected by an extremely expensive part that will fail first
in order to protect the 25 cent fuse.

Harvey




On 2018-10-13 05:49 PM, Dennis Tillman W7PF wrote:
On behalf of all of us thank you Håkan once again.

Of course I know what Fold Back Current Limiting is. In its simplest terms it is a circuit that prevents you from burning up a valuable instrument while you are tinkering around inside it with a screwdriver or other metal tool. One of Murphy Law's guarantees that the more careful you are, the more catastrophic the damage you will cause. Fold back Current Limiting is designed to sacrifice active devices such as transistors and ICs in order to protect the fast blow fuse from stress.

"tinkera123" also asked what the acronym ULU meant. I was hoping someone would explain it. The specific sentence it is used in doesn't give much to go on:
"Some suggestions for the wiring interface to the ULU are offered."
This is followed by 5 suggestions.

From the suggestions it sounds like they are talking about a Device Under Test but the well-known acronym for this is DUT. Some companies use Unit Under Test or UUT.
So far no one has offered an explanation for ULU. I can't think of anything that fits those letters and there are very few ULU acronyms.

The closest I could up with is Unit Under Load which might mean a set of standard load resistors attached to a male connector that plugs into the backplane and loads the power supply enough to draw the maximum amount of power from each supply that the slot should be able to supply. But a Unit Under Load would be UUL. As anyone who plays Scrabble knows, the order of the letters can be really important.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
tinkera123
Sent: Friday, October 12, 2018 3:34 PM
Subject: Re: [TekScopes] 7000-series power-hungry plug-ins

Regarding this pdf of 7000 series currents ..... I am unfamiliar with the
terms Foldback currents and ULU.
Can some-one please explain??

-Chuck Harris

PS, thanks to Håkan for the 7904 power supply capacity note.


 

On Sun, Oct 14, 2018 at 02:49 AM, Dennis Tillman W7PF wrote:


So far no one has offered an explanation for ULU. I can't think of anything
that fits those letters and there are very few ULU acronyms.
How about Universal Load Unit referring to the 067-fixtures mentioned
in the headline of the first page.
/Håkan

 

Hi Håkan,

After your post I re-read the two pages you provided but I still do not see the headline on the first page that says Universal Load Unit. I think ULU must be defined on a different page from the two pages you scanned.

I re-read this 5 times and I still don't see it. Maybe this is a case of RTFM but I don't think so.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
zenith5106
Sent: Sunday, October 14, 2018 2:50 AM

On Sun, Oct 14, 2018 at 02:49 AM, Dennis Tillman W7PF wrote:


So far no one has offered an explanation for ULU. I can't think of
anything that fits those letters and there are very few ULU acronyms.
How about Universal Load Unit referring to the 067-fixtures mentioned in
the headline of the first page.
/Håkan



--
Dennis Tillman W7PF
TekScopes Moderator

 

On Sun, Oct 14, 2018 at 05:47 PM, Dennis Tillman W7PF wrote:


After your post I re-read the two pages you provided but I still do not see
the headline on the first page that says Universal Load Unit. I think ULU must
be defined on a different page from the two pages you scanned.
It's not defined on any of the pages. What I meant was that it referred to the
067-0883-99 / 067-0919-99 which are on the top of the page.
067-0883-99 is a Universal Load Unit and IIRC the 067-0919-99 was used to program it.
/Håkan

 

Hi Håkan,
I have never come across the 067-0883-99 Universal Load Unit before now. There was only one hit on google but that had no picture or information.
It is not listed in the Calibration Fixtures Catalogs so I have no idea even what it looks like.
Ditto for the 067-0919-99 Programmer. No hits at all on google

Is there any chance you have photos of these units or a manual?

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
zenith5106
Sent: Sunday, October 14, 2018 11:27 AM
On Sun, Oct 14, 2018 at 05:47 PM, Dennis Tillman W7PF wrote:

After your post I re-read the two pages you provided but I still do
not see the headline on the first page that says Universal Load Unit.
I think ULU must be defined on a different page from the two pages you
scanned.
It's not defined on any of the pages. What I meant was that it referred
to the
067-0883-99 / 067-0919-99 which are on the top of the page.
067-0883-99 is a Universal Load Unit and IIRC the 067-0919-99 was used
to program it.
/Håkan



--
Dennis Tillman W7PF
TekScopes Moderator

 

On Sun, Oct 14, 2018 at 09:05 PM, Dennis Tillman W7PF wrote:


I have never come across the 067-0883-99 Universal Load Unit before now.

Is there any chance you have photos of these units or a manual?
Dennis, I may be totally out in the blue here ...... but, I have a vague memory that we had one in our field office.
If it is the one I think of I don't think it was ever used or at least not often. Again from a fading memory, it was a
multi channel electronic load and it looked like being built into a 7603 chassi and used a 7k style plugin
for programming using various resitors. I have no idea what happened to it. It may have gone to another field office or
just been scrapped.
Not many of the -99 fixtures, if any, were listed in the Calibration Fixtures Catalog.
I have tried to find info about it in the microfiche but so far not found any.
Maybe some of the guys in the group who worked in the factory could confirm or prove me wrong in what I just said.
/Håkan

Leo Potjewijd
 

My best guess is an Unified (or Universal) Load Unit, something like a
calibrator for power supplies...

Just my EUR0.02.

Leo Potjewijd
 

Oops. forgot all about the delay caused by the webmail digest...
Apologies for wasted BW.

Tim
 

On Sun, Oct 14, 2018 at 12:05 PM, Dennis Tillman W7PF wrote:


Hi Håkan,
I have never come across the 067-0883-99 Universal Load Unit before now. There
was only one hit on google but that had no picture or information.
It is not listed in the Calibration Fixtures Catalogs so I have no idea even
what it looks like.
Ditto for the 067-0919-99 Programmer. No hits at all on google

Is there any chance you have photos of these units or a manual?

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
zenith5106
Sent: Sunday, October 14, 2018 11:27 AM
On Sun, Oct 14, 2018 at 05:47 PM, Dennis Tillman W7PF wrote:

After your post I re-read the two pages you provided but I still do
not see the headline on the first page that says Universal Load Unit.
I think ULU must be defined on a different page from the two pages you
scanned.
It's not defined on any of the pages. What I meant was that it referred
to the
067-0883-99 / 067-0919-99 which are on the top of the page.
067-0883-99 is a Universal Load Unit and IIRC the 067-0919-99 was used
to program it.
/Håkan



--
Dennis Tillman W7PF
TekScopes Moderator
Hi Dennis,
You saw one and didn't even know it.
At last years Rickreall ham show I pointed out the funny looking 7000 series case under a vendors table, but it didn't spark your interest.
I picked it up for 20 bucks and have been wondering ever since what it was used for.
I created an album located here:
https://groups.io/g/TekScopes/album?id=75949
(did I do the picture link right?)
I wonder what else is needed to complete the test setup?
Regards,
Tim

 

On Wed, Oct 17, 2018 at 03:37 AM, Tim wrote:


At last years Rickreall ham show I pointed out the funny looking 7000 series
case under a vendors table, but it didn't spark your interest.
I picked it up for 20 bucks and have been wondering ever since what it was
used for.
I created an album located here:
https://groups.io/g/TekScopes/album?id=75949
Yes that's exactly the one I was thinking about. So my memory wasn't so bad after all.
/Håkan