Test Equipment Anonymous (TEA) group therapy thread

[bd139]

The most aggressive thing on the planet is one of those dogs that approximates a rat on a bit of string. I think it's an inherent part of nature.

[AVGresponding]

@med will you be joining the voice channel ? That would be kinda nice, my English is getting rusty

For you My Dear I'll join the voice channel but you may not be able to hear me over the racket. 

Gaaah... Med does not speak English, he speaks "Ameringlish".

Spec does not speak English, he speaks "Southern English".

I will be on discord, in order to speak English.

I hope that is perspicacious. *tips hat*


EDIT: Also SHHHH, I'm 70% through my Star Trek binge, don't interrupt

[Cerebus]

I hope that he was not referring to me with that statement because I can assure you all that I'm not a small man, being 6ft 4" tall and built like the proverbial brick sh1t house with such large hands that I struggle to find any gloves to fit me 

Lordy, most definitely NO! I have in mind one person who seems to suffer from oppositional defiance disorder - they will say something seemingly just to disagree with people and when someone presents facts that disprove their position they just make shit up to prove their point. I've never seen you do anything remotely like that.

[Specmaster]

@med will you be joining the voice channel ? That would be kinda nice, my English is getting rusty

For you My Dear I'll join the voice channel but you may not be able to hear me over the racket. 

Gaaah... Med does not speak English, he speaks "Ameringlish".

Spec does not speak English, he speaks "Southern English".

I will be on discord, in order to speak English.

I hope that is perspicacious. *tips hat*


EDIT: Also SHHHH, I'm 70% through my Star Trek binge, don't interrupt

Spec most certainly doesnt speak Southern English, whatever that is, my family are always pulling me up on the way I pronounce some words, so I'd say that seeing I'm Essex born, I speak Essex English 

[Specmaster]

The most aggressive thing on the planet is one of those dogs that approximates a rat on a bit of string. I think it's an inherent part of nature.

Yep, I too think of small dogs as ultra aggressive, big dogs like Alsatians etc are generally pretty laid back and chilled I find.

[factory]

I accidentally bought that Beckman counter I was watching, as it went down to $30, shipping is still a killer on it though. 

What kind of display is this?

Until it arrives your guess is as good as mine, I couldn't find any info on it last time I posted about it when it was $50, I did find another (older?) version with neon number readout bulbs here; http://crasno.ca/articles/Beckman6148A.htm

David

Looks like a blue version of a panaplex to me, surely some sort of vfd at any rate?

I think your on to something there, I wasn't sure as they look to neat to be individual VFD tubes, could it be a multi-digit version of this (nearest to digit appearance)?


David

Well the Beckman counter arrived this week, I asked them to pack it well so that the front wouldn't get anymore damaged than it was in the listing, unfortunately they packed it amazon style  , the front survived but a chuck of cast alloy has been broken off the case at the rear and I couldn't get the cover off easily. 

Anyway here is a picture of the display, I think I have worked out what it is and it's not a VFD.


It's quite heavy for it's size too (over 21kg) & only has one carrying handle, hopefully the fan will be super noisy. 

David

[Cerebus]

There is no sine wave generation here;

Yeah, there is. Well, more often a dirty trapezoidal approximation. I just don't think you've realised it's there. Just as the PWM burried inside an old ARB from the days before fast DACs can produce a sine wave when filtered, so does the PWM from motor controller when filtered through the resistance and inductance of the motor windings. (Some motors have windings distributed in such a way that at trapezoid is the right way to drive them, some want a pukka sinewave.)

These show phase to ground voltages on the output of an RC model's ESC. Remember this is a three phase Y motor so to get phase-to-phase voltages or phase-to-Y you have to do some arithmetic on the waveforms shown to get there.

Look at the envelope -  a messy trapezoid.



Similar sort of thing:

[Saskia]

@bd139
Here's Wile E. Coyote ...

[Cerebus]

BD139 and I have been having a side conversation about dashcams. A colleague of his recommended one, and I was just going to look it up. Here's the search results:



Why, oh why, am I being shown an advert for a supplier of nematode worms when searching for a dashcam. I've seen some misdirected ads before but this takes the biscuit. This is on DuckDuckGo, so there's no search history or profile to misdirect things, like if I'd been searching for worming tablets for the dragon cat; anyway, I haven't been.

[bd139]

BD139 and I have been having a side conversation about dashcams. A colleague of his recommended one, and I was just going to look it up. Here's the search results:



Why, oh why, am I being shown an advert for a supplier of nematode worms when searching for a dashcam. I've seen some misdirected ads before but this takes the biscuit. This is on DuckDuckGo, so there's no search history or profile to misdirect things, like if I'd been searching for worming tablets for the dragon cat; anyway, I haven't been.

Mac? Needs more adblocking

[Mr. Scram]

The impression I get of the principal suspect I'm talking about is of an being old, small and wizened, I have no clue as to their actual physical characteristics. On the Internet no one knows you're a dog or indeed a very small man. I've never associated [imagined] physical characteristics with the degree of pugnacious of people online. When I have had some genuine clue to the stature of people online I've sometimes noticed the "little man effect", where unusually small men try to compensate with aggressiveness. Both the men that I've known in real life who are highly likely to start a bar room brawls were both obviously short (and Scots, but experience of the Scots suggests that attribute had nothing to do with their attitude).

I vehemently deny any rumours about being a dog. The small man effect sounds familiar, although being physically small is far from the only reason for it.

[Cerebus]

The impression I get of the principal suspect I'm talking about is of an being old, small and wizened, I have no clue as to their actual physical characteristics. On the Internet no one knows you're a dog or indeed a very small man. I've never associated [imagined] physical characteristics with the degree of pugnacious of people online. When I have had some genuine clue to the stature of people online I've sometimes noticed the "little man effect", where unusually small men try to compensate with aggressiveness. Both the men that I've known in real life who are highly likely to start a bar room brawls were both obviously short (and Scots, but experience of the Scots suggests that attribute had nothing to do with their attitude).

I vehemently deny any rumours about being a dog. The small man effect sounds familiar, although being physically small is far from the only reason for it.

Aw, c'mon. Tggzzz owned up (the name's a giveaway). Let's try out how that sounds: "Scram, who's a good boy? Who is? Who is?", "SCRAM! Stop chasing Fenton". Yeah, passes the "sounds right" test. 

[Cerebus]

Mac? Needs more adblocking

I let DuckDuckGo have a pass. They manage to serve me ads without using any of the many domains in my DNS firewall policy zone file, nowhere else does.

[tggzzz]

The impression I get of the principal suspect I'm talking about is of an being old, small and wizened, I have no clue as to their actual physical characteristics. On the Internet no one knows you're a dog or indeed a very small man. I've never associated [imagined] physical characteristics with the degree of pugnacious of people online. When I have had some genuine clue to the stature of people online I've sometimes noticed the "little man effect", where unusually small men try to compensate with aggressiveness. Both the men that I've known in real life who are highly likely to start a bar room brawls were both obviously short (and Scots, but experience of the Scots suggests that attribute had nothing to do with their attitude).

I vehemently deny any rumours about being a dog. The small man effect sounds familiar, although being physically small is far from the only reason for it.

Aw, c'mon. Tggzzz owned up (the name's a giveaway).

Er, owned up to what, and why is that randomly chosen[1] name ame a giveaway?

[1] for simplicity, to avoid moniker collisions which would just confuse me.

Let's try out how that sounds: "Scram, who's a good boy? Who is? Who is?", "SCRAM! Stop chasing Fenton". Yeah, passes the "sounds right" test. 

[Cerebus]

Er, owned up to what, and why is that randomly chosen[1] name ame a giveaway?

"On the Internet no one knows you're a dog"

Or in quaint British.......a trolley. 

A trolley carries Tea, or cakes, or similar comestibles. A cart has a horse in front of it. A barrow is the human powered equivalent of a cart, so I think that's a barrow; which would make you a Barrow boy.

So what does that make this?

A stereo photo of you delivering milk when you were a lad? A bit before you got the original prehistoric Rocky Horror T-shirt? 

"On the Internet, nobody knows you're a dog"

Edited to add: And I'm sure that everybody here would agree that "Who's a good boy?" could be answered by "Tggzzz is. Yes he is".

Drat. Secret's out.

[1] for simplicity, to avoid moniker collisions which would just confuse me.

Let's try out how that sounds: "Scram, who's a good boy? Who is? Who is?", "SCRAM! Stop chasing Fenton". Yeah, passes the "sounds right" test. 

It just looks like how a dog, called Tigger, Tiggz for short, would type his name when he was first getting the hang of using a keyboard. 

[BU508A]

and now for something completely different:


today arrival:



Christmas bakery is starting by end of November ...

[tggzzz]

Er, owned up to what, and why is that randomly chosen[1] name ame a giveaway?

"On the Internet no one knows you're a dog"

Or in quaint British.......a trolley. 

A trolley carries Tea, or cakes, or similar comestibles. A cart has a horse in front of it. A barrow is the human powered equivalent of a cart, so I think that's a barrow; which would make you a Barrow boy.

So what does that make this?

A stereo photo of you delivering milk when you were a lad? A bit before you got the original prehistoric Rocky Horror T-shirt? 

"On the Internet, nobody knows you're a dog"

Edited to add: And I'm sure that everybody here would agree that "Who's a good boy?" could be answered by "Tggzzz is. Yes he is".

Drat. Secret's out.

[1] for simplicity, to avoid moniker collisions which would just confuse me.

Let's try out how that sounds: "Scram, who's a good boy? Who is? Who is?", "SCRAM! Stop chasing Fenton". Yeah, passes the "sounds right" test. 

It just looks like how a dog, called Tigger, Tiggz for short, would type his name when he was first getting the hang of using a keyboard. 

Very imaginative, too imaginative. Like a Rorsasch test, you have found meaning where none exists.

Sigmund Freud was a prat, but he did get one thing right: "sometimes a cigar is just a cigar".

[Cerebus]

Very imaginative, too imaginative. Like a Rorsasch test, you have found meaning where none exists.

Ah, so I'm a zen comedian now am I. What is the sound of one hand cl... Ow my ear!

Edit: Probably time to get the old 'soggy old boot' umbrella out again.

[BU508A]

Very imaginative, too imaginative. Like a Rorsasch test, you have found meaning where none exists.

Ah, so I'm a zen comedian now am I. What is the sound of one hand cl... Ow my ear!

Edit: Probably time to get the old 'soggy old boot' umbrella out again.

Hmmmm....



  

[mnementh]

There is no sine wave generation here;

Yeah, there is. Well, more often a dirty trapezoidal approximation. I just don't think you've realised it's there. Just as the PWM burried inside an old ARB from the days before fast DACs can produce a sine wave when filtered, so does the PWM from motor controller when filtered through the resistance and inductance of the motor windings. (Some motors have windings distributed in such a way that at trapezoid is the right way to drive them, some want a pukka sinewave.)

These show phase to ground voltages on the output of an RC model's ESC. Remember this is a three phase Y motor so to get phase-to-phase voltages or phase-to-Y you have to do some arithmetic on the waveforms shown to get there.

Look at the envelope -  a messy trapezoid.

   Similar sort of thing:   

Oh, good lord, here we go again; same old argument as trying to explain to a plank pilot why quadcopter ESCs need to be so different from plank ESCs... 

That's a waveform from an old eFlite plank ESC; literally more than a decade old in terms of design technology. They operate at about 1/100 the RPMs of a modern quadcopter ESC, and they were DELIBERATELY trying to do MSW the same way as some AC inverters do to get "smoother power" because low-KV motors will shake a wooden craft to bits if they start "cogging" at low RPM. They were able to do this because the demands were so low on the processor. Many of these ESCs actually have a governor feature in them that can be turned on to provide a fixed RPM for helicopter use.

That is literally not even the same species as a multirotor ESC. Yeah, sure, you can see something sortof like that waveform with a multirotor motor & ESC... only far fewer steps in the waveform and a lot more noise because it is literally commutation going on (the ESC people's term, not mine), not any attempt at sine wave generation.

I spent a lot of time at the beginning of my multirotor journey trying to reconcile my conventional knowledge of conventional industrial speed control with how these ESCs work. In the end, I came to realize this was not a case of "derivative" as much as "divergent evolution" from a really old fork in the way back when. The needs of an aircraft that uses varying speeds of motors to fly, steer and keep itself level are completely different from anything that has gone before. As long as you keep trying to fit MR ESCs into any existing boxes, the less sense they'll make.

mnem

[Specmaster]

@bd139 and Cerebus If your both thinking about getting a dashcam, you could do a lot of worse than getting a NextBase 512GW, there are plenty of videos about it on YT and it also has the ability to add a rear camera and record both at the same time. I myself have one and only have the front unit which as a single unit will also record at 1440 HD+, has Wi-Fi built in which will pair up with a mobile phone for file transfer. I like it a lot.

[Cerebus]

@bd139 and Cerebus If your both thinking about getting a dashcam, you could do a lot of worse than getting a NextBase 512GW, there are plenty of videos about it on YT and it also has the ability to add a rear camera and record both at the same time. I myself have one and only have the front unit which as a single unit will also record at 1440 HD+, has Wi-Fi built in which will pair up with a mobile phone for file transfer. I like it a lot.

This was prompted by the number of attempted suicide victims I met on the roads today who seemed to want to make me the means of their exit from the world.

I did have one last year but had to RTM/RMA it because half the video it recorded was scrambled. That was a NextBase, forget which model, so I'm not going there again. I just picked on BD139 for a recommendation becuase of him mentioning one he was using a while back and I trust his judgement. Turns out that one fried itself in the summer. He got a recommendation from one of his colleagues that looks hopeful.

[mnementh]

I don't dare have a dashcam; especially up here. I drive like a complete asshole compared to most of the Canucks on the highway. 

I blame decades of driving in the capitol of Dumbfuckistan. 

mnem

[mnementh]

OMG, mnem strikes again.       

I can haz tzzzzt...?

mnem
 

[Cerebus]

There is no sine wave generation here;

Yeah, there is. Well, more often a dirty trapezoidal approximation. I just don't think you've realised it's there. Just as the PWM burried inside an old ARB from the days before fast DACs can produce a sine wave when filtered, so does the PWM from motor controller when filtered through the resistance and inductance of the motor windings. (Some motors have windings distributed in such a way that at trapezoid is the right way to drive them, some want a pukka sinewave.)

These show phase to ground voltages on the output of an RC model's ESC. Remember this is a three phase Y motor so to get phase-to-phase voltages or phase-to-Y you have to do some arithmetic on the waveforms shown to get there.

Look at the envelope -  a messy trapezoid.

   Similar sort of thing:   

Oh, good lord, here we go again; same old argument as trying to explain to a plank pilot why quadcopter ESCs need to be so different from plank ESCs... 

That's a waveform from an old eFlite plank ESC; literally more than a decade old in terms of design technology. They operate at about 1/100 the RPMs of a modern quadcopter ESC, and they were DELIBERATELY trying to do MSW the same way as some AC inverters do to get "smoother power" because low-KV motors will shake a wooden craft to bits if they start "cogging" at low RPM. They were able to do this because the demands were so low on the processor. Many of these ESCs actually have a governor feature in them that can be turned on to provide a fixed RPM for helicopter use.

That is literally not even the same species as a multirotor ESC. Yeah, sure, you can see something sortof like that waveform with a multirotor motor & ESC... only far fewer steps in the waveform and a lot more noise because it is literally commutation going on (the ESC people's term, not mine), not any attempt at sine wave generation.

I spent a lot of time at the beginning of my multirotor journey trying to reconcile my conventional knowledge of conventional industrial speed control with how these ESCs work. In the end, I came to realize this was not a case of "derivative" as much as "divergent evolution" from a really old fork in the way back when. The needs of an aircraft that uses varying speeds of motors to fly, steer and keep itself level are completely different from anything that has gone before. As long as you keep trying to fit MR ESCs into any existing boxes, the less sense they'll make.

mnem

The exact model of ESC doesn't matter - I just did an image search and picked the first couple of waveforms that looked right. What matters is that it controlling a BLDC motor.

Mnem, this is about how BLDC/PMSM motors work, no more no less. It has nothing to do with the application. BLDC motors do not blow themselves up if they have no load, etc. etc. It doesn't matter is the BLDC motor is a lift motor on a quadcopter or a servo on a CNC axis, it's still a BLDC motor. I've got two of the quadcopter type external rotor motors here, I've also got two small circa 50W "just a motor" BLDC motors. They are all the same electrically. Three phases, Y wired, a bunch of stator poles, a bunch of permanent magnet poles, that's it all for the 'motor' part. They take the same electrical signals to make them go around in the same way, the physics of magnetism dictate how they work, they all work the same. The torque/speed curves of all of them are the same fundamental shape and so on.

By pure coincidence I've spent some not inconsiderable amount of my time for the last few months reading real text books on the subject, watching loads of videos on the subject, including the whole of a two day TI seminar on the topic. I don't claim to be an expert, but I can claim to know enough to say "Hold on, that doesn't sound right" or "Yeah, that sounds right". Robert clearly knows what he's talking about. A lot of what you've said doesn't make sense. I pitched in to try to give you a face saving way of coming around and you're refusing to take it. So be it, it's your loss.