Test Equipment Anonymous (TEA) group therapy thread

[Cerebus]

 

 

[bd139]

Last I checked they will not provide you even with access to software images unless you are a paid support contract customer.

Just a point on Cisco stuff. There's a way round this. You just hit the software download section of cisco.com and find the package you need. It gives you the file name and the SHA512. Then instantly whack the thing into google and you usually find it direct download. Then just SHA it, TFTP it up and you're done 

[Cerebus]

so congratulations on snagging the one unit every time nut drools over.

Damn! Now you got me reading up on it. I want it for my experiments at work. I've expensed Ethernet taps off Ebay before. Now, I wonder how to pull this off..

Have a read of the August 1978 HP Journal article on the HP5370A. It uses a clever combination of two techniques, vernier counting and triggered phase locked loops. If I can dream up a way to create the triggered PLL VCOs without a hybrid (as used in the 5370) I'm gonna design me one. I can do something similar, but not as precise or as satisfying with dual slope time interpellators for the start and stop pulses. There's also a possibility of using something like the Texas TDC7200 time to digital converter to do the timing between start/stop pulses and a standard clock. But the triggered vernier oscillators is so elegant that it would be a shame not to steal the technique if at all possible.

[tggzzz]

Ooooh just discovered this wonderful IC: http://images.100y.com.tw/pdf_file/TLP598G.pdf

If you think that's fun, have a ponder on the possibilities when using these: HCNR200 and HCNR201 High-Linearity Analog Optocouplers.

I was playing with these last week trying to design an 1.4kV isolated, battery powered, amplifier with them for making floating DC measurements. As always with anything involving a photodiode and a transimpedance amplifier getting enough bandwidth is the issue. In theory these will run to 1MHz, getting there is another question. Gave up in disgust at ~50kHz and I'll go back to it once it's spent enough time on the virtual 'healing bench'.

Isolation products have come on leaps and bounds over the past few years: optocouplers are long in the tooth, 150Mb/s is easy now.

Have a look at https://www.analog.com/en/parametricsearch/11444#/ to see one manufacturer's offerings.

[drussell]

It uses a clever combination of two techniques, vernier counting and triggered phase locked loops. If I can dream up a way to create the triggered PLL VCOs without a hybrid (as used in the 5370) I'm gonna design me one. I can do something similar, but not as precise or as satisfying with dual slope time interpellators for the start and stop pulses. There's also a possibility of using something like the Texas TDC7200 time to digital converter to do the timing between start/stop pulses and a standard clock. But the triggered vernier oscillators is so elegant that it would be a shame not to steal the technique if at all possible.

Indeed.

I find many of those innovative techniques from the old, original HP era (especially in the 60s-70s era) are absolutely mind-bogglingly clever, even through the lens of time today.  Fantastic engineering minds came up with these simply fascinating ideas for ways to do things.  It shows that there was a real, deep understanding of the problems involved which allowed some utterly ingenious solutions. 

[Cerebus]

Ooooh just discovered this wonderful IC: http://images.100y.com.tw/pdf_file/TLP598G.pdf

If you think that's fun, have a ponder on the possibilities when using these: HCNR200 and HCNR201 High-Linearity Analog Optocouplers.

I was playing with these last week trying to design an 1.4kV isolated, battery powered, amplifier with them for making floating DC measurements. As always with anything involving a photodiode and a transimpedance amplifier getting enough bandwidth is the issue. In theory these will run to 1MHz, getting there is another question. Gave up in disgust at ~50kHz and I'll go back to it once it's spent enough time on the virtual 'healing bench'.

Isolation products have come on leaps and bounds over the past few years: optocouplers are long in the tooth, 150Mb/s is easy now.

Have a look at https://www.analog.com/en/parametricsearch/11444#/ to see one manufacturer's offerings.

Oh yeah, a list of lots of fast digital isolators.

Look again. I said 1MHz not 1Mb/s. Sure you can get 1s and 0s across an isolated wire very quickly, but how many uV and mV can you get across there? The interesting thing about the HCNR200 and friends is getting analogue quantities across an isolation gap with something like 0.01% linearity (0.05% worst case) at very low cost. Or to put it differently, any idiot can count to 1 really quickly...

Granted there are a small handful of isolated ADCs in that list, but then you've got to convert back to analogue. So a DAC, a micro or FPGA etc. etc. Rather more of a BOM than a couple of op amps and a sprinkling of passives with a linear optoisolator that costs £2.50 (1 off - £1.50 in quantity).

[bd139]

These optoisolators are quite interesting. I'm looking at them to build a small and pointless telephone exchange from scratch (on my bucket list)  . Less annoying than relays

[Cerebus]

Keithley use similar photo-fet and photo-mos parts for input range switching on some of their DMMs. Sometimes they use a TLP591B, which is an LED and a stack of photodiodes, to drive the gates of discrete JFETs and MOSFETs to make up a switching matrix (e.g. Keithley 2001).

In theory, these don't have the charge injection problems that you get with non-isolated MOSFET switches. How well it works in practice is another question, because you've still got some capacitive coupling across the isolation barrier.

[tggzzz]

These optoisolators are quite interesting. I'm looking at them to build a small and pointless telephone exchange from scratch (on my bucket list)  . Less annoying than relays

I've seen telecom switches from the late 60s built from a incandescant lightbulb surrounded by four 1"*1" LDRs, was coated, naturally. I probably still have some of the LDRs.

I have no idea whether it was put in to production!

[tggzzz]

Ooooh just discovered this wonderful IC: http://images.100y.com.tw/pdf_file/TLP598G.pdf

If you think that's fun, have a ponder on the possibilities when using these: HCNR200 and HCNR201 High-Linearity Analog Optocouplers.

I was playing with these last week trying to design an 1.4kV isolated, battery powered, amplifier with them for making floating DC measurements. As always with anything involving a photodiode and a transimpedance amplifier getting enough bandwidth is the issue. In theory these will run to 1MHz, getting there is another question. Gave up in disgust at ~50kHz and I'll go back to it once it's spent enough time on the virtual 'healing bench'.

Isolation products have come on leaps and bounds over the past few years: optocouplers are long in the tooth, 150Mb/s is easy now.

Have a look at https://www.analog.com/en/parametricsearch/11444#/ to see one manufacturer's offerings.

Oh yeah, a list of lots of fast digital isolators.

Look again. I said 1MHz not 1Mb/s. Sure you can get 1s and 0s across an isolated wire very quickly, but how many uV and mV can you get across there? The interesting thing about the HCNR200 and friends is getting analogue quantities across an isolation gap with something like 0.01% linearity (0.05% worst case) at very low cost. Or to put it differently, any idiot can count to 1 really quickly...

Granted there are a small handful of isolated ADCs in that list, but then you've got to convert back to analogue. So a DAC, a micro or FPGA etc. etc. Rather more of a BOM than a couple of op amps and a sprinkling of passives with a linear optoisolator that costs £2.50 (1 off - £1.50 in quantity).

Oh, I know what your proposed solution was, but you didn't vouchsafe your problem to which that was the solution.

The devil will be in the details of those optoisolators; I'll bet they have "features" not mentioned in the datasheet. Exception: if there is a relevant application note or example circuit.

[bd139]

These optoisolators are quite interesting. I'm looking at them to build a small and pointless telephone exchange from scratch (on my bucket list)  . Less annoying than relays

I've seen telecom switches from the late 60s built from a incandescant lightbulb surrounded by four 1"*1" LDRs, was coated, naturally. I probably still have some of the LDRs.

I have no idea whether it was put in to production!

Interesting. Vactrols! Probably never worked properly as they wear out I understand. Or did when light bulbs were the source.

[0culus]

https://groups.io/g/HP-Agilent-Keysight-equipment/topic/surprise_new_stash_of_hp/73150042

An HPAK list user found a rather well hidden directory of manuals that are NOT in the normal places on Keysight's website. Definitely worth looking and seeing if any obscure ones you've been looking for are there.

[mnementh]

@mnem, Canada has it gunmen to then it seems, how far away was incident from you? Particularly devious of him to disguise himself and car as a police unit.

The difference is the numbers (16, including one Police Officer in the line of duty), and the fact that the entire nation is shocked:

The shooting is one of the worst in Canada's history. The country overhauled its gun-control measures after a gunman killed 14 women and himself at Montreal’s Ecole Polytechnique college in 1989. This weekend's shooting is the deadliest since then.

This event wouldn't even make a blip on the RADAR in Texas; probably no more than the local news if Trump was doing something particularly stupid and evil.

mnem

[Cerebus]

Oh, I know what your proposed solution was, but you didn't vouchsafe your problem to which that was the solution.

The devil will be in the details of those optoisolators; I'll bet they have "features" not mentioned in the datasheet. Exception: if there is a relevant application note or example circuit.

But you proffer your own solution, not knowing what the problem was - one must presume that the pointer to lots of high bandwidth optocouplers was 'a solution' of sorts not a "you do realise that there are faster parts don't you?". One hopes that you wouldn't be that crass. I didn't actually state what the problem was or even ask for any solutions, I just said what I'd been doing and moreover in the context of 'less usual opto parts'. I'm assuming that you know these have one LED and two photodiodes inside and their ability to be linearised by putting one in the front-side feedback loop is what makes them interesting. Knowing that I'm at a loss as to why you thought pointing out a pile of essentially digital opto parts would be interesting in context? Given that, one's natural assumption was that you'd missed the point: 'analogue'. For what it's worth the actual underlying problem was "These are interesting parts, I've been meaning to play with them, let's try one in a simple application and see what they do".

[mnementh]

Rev 2 now printing...

mnem
"The role of Failure in Design..."

[Cerebus]

@mnem, Canada has it gunmen to then it seems, how far away was incident from you? Particularly devious of him to disguise himself and car as a police unit.

The difference is the numbers (16, including one Police Officer in the line of duty), and the fact that the entire nation is shocked:

The shooting is one of the worst in Canada's history. The country overhauled its gun-control measures after a gunman killed 14 women and himself at Montreal’s Ecole Polytechnique college in 1989. This weekend's shooting is the deadliest since then.

This event wouldn't even make a blip on the RADAR in Texas; probably no more than the local news if Trump was doing something particularly stupid and evil.

mnem

What's notable to me about this is that while Canada has a good record on mass shootings (i.e. there have been few of them) there is a relatively high level of firearms ownership. If you were to compare the UK and Canada they have roughly similar records on mass shootings but if you compare private civilian firearms ownership Canada comes in at 34.7 firearms per 100 people, whereas the UK has 3.44 per 100 people (and I happen to know that the UK figure is heavily slanted towards "shotguns owned by farmers" rather than pistols and rifles). I think this perversely supports the "guns don't kill people, people kill people" argument oft lofted by the US's 2nd amendment nuts, the only problem is the propensity for the "people" bit in some countries to be rather more of a problem than in others.

[tggzzz]

These optoisolators are quite interesting. I'm looking at them to build a small and pointless telephone exchange from scratch (on my bucket list)  . Less annoying than relays

I've seen telecom switches from the late 60s built from a incandescant lightbulb surrounded by four 1"*1" LDRs, was coated, naturally. I probably still have some of the LDRs.

I have no idea whether it was put in to production!

Interesting. Vactrols! Probably never worked properly as they wear out I understand. Or did when light bulbs were the source.

Never knew that name! The ones I can google are a lot smaller that a >1 inch cube.

Incandescant bulbs can have a long lifetime, iff they aren't too bright.

[med6753]

@mnem, Canada has it gunmen to then it seems, how far away was incident from you? Particularly devious of him to disguise himself and car as a police unit.

The difference is the numbers (16, including one Police Officer in the line of duty), and the fact that the entire nation is shocked:

The shooting is one of the worst in Canada's history. The country overhauled its gun-control measures after a gunman killed 14 women and himself at Montreal’s Ecole Polytechnique college in 1989. This weekend's shooting is the deadliest since then.

This event wouldn't even make a blip on the RADAR in Texas; probably no more than the local news if Trump was doing something particularly stupid and evil.

mnem

What's notable to me about this is that while Canada has a good record on mass shootings (i.e. there have been few of them) there is a relatively high level of firearms ownership. If you were to compare the UK and Canada they have roughly similar records on mass shootings but if you compare private civilian firearms ownership Canada comes in at 34.7 firearms per 100 people, whereas the UK has 3.44 per 100 people (and I happen to know that the UK figure is heavily slanted towards "shotguns owned by farmers" rather than pistols and rifles). I think this perversely supports the "guns don't kill people, people kill people" argument oft lofted by the US's 2nd amendment nuts, the only problem is the propensity for the "people" bit in some countries to be rather more of a problem than in others.

Why are we posting this crap here? Doesn't belong here. I'm almost to the point where I'm going to break my rule of no political commentary which drive the anti gun nuts ape and certainly also get the dragon fired up and down the hell hole we go.

Stop.   

[bd139]

Shots fired 

Seriously though I agree.

[WastelandTek]

the real shooting is going to start soon enough, no need to start it in here

[AVGresponding]

So, another day done at the madhouse...

The joiners are behind, and the sparkies are ahead, and being told to slow down. The site manager (this term is very loosely applied) has been getting everyone's backs up (normal for him, as it happens), shouting matches aplenty...

Being ahead in our work gives us time for other activities, such as re-arranging notice boards:




My latest acquisition just arrived via knock-a-door-run ParcelForce, initial dead tests look promising, just needs cleaning and fettling as far as I can tell:



The slight frown is quite cute, in a way, but I will be straightening it out   



I think I may just about qualify for a award as the price paid was £0.99 + £10 p&p


EDIT: Added thumbnail attachments for better image quality.

[bd139]

That is indeed jammy git award worthy.

Waiting for a UPS still here. Supposed to be here today. 19:32 not looking likely.

[Cerebus]

Why are we posting this crap here? Doesn't belong here. I'm almost to the point where I'm going to break my rule of no political commentary which drive the anti gun nuts ape and certainly also get the dragon fired up and down the hell hole we go.

Stop.

Except that it's not political, it's commentary on current affairs. I find, what was it, 16 people getting gunned down in Canada saddening and tragic. To not comment on it because some people have a bee in their bonnets about gun ownership (former long range target shooter here, so I'm not an anti-gun nut, I rather like guns) would be heartless and cowardly. This is the 'pub' and just like the pub, if you've strong feelings on a topic that gets a passing mention, you've the choice of either just shrugging your shoulders and letting it go, or starting a row. I was going to have nothing more to say on the issue, I simply found the relatively high gun ownership in Canada while not causing problems a curious and interesting point - I'd not considered it before because I hadn't had my attention draw to it by an incident like this before. That was literally all I was going to say on the subject until you decided that it was verboten Politik. That response, and that alone provokes this comment. Among rational adults, my prior observation ought to be something that provokes thought, not a knee jerk response.

Nothing more to say on the subject.

[Cerebus]

My latest acquisition just arrived via knock-a-door-run ParcelForce, initial dead tests look promising,...

In my youth the children's game of knocking at someone's door and running away was known as "Knock Down Ginger". Nobody that I've asked has ever adequately explained why that was the name, or even why it was a good game, but it was. Given that in these days of Political Correctness there are only two groups that it's permitted for an Englishman to express prejudice against, Gingers* and Frenchmen, I propose that henceforth Parcelforce employees should be dubbed "Gingers".

* If you can't tell the difference between a Ginger and a Redhead, this is not the conversation for you.

[tautech]

Cerebus, also keen shooter here downunder. 
What calibres (English spelling just to wind up the Yanks) did you use for LR ?