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Mains voltage zero crossing detector with optical isolated output

I'm not. I don't give a rat's ass about zero crossings ;-) At least until the problem comes up IRL... then I'll design a chip that does it right. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson
Loading thread data ...

--
I don't try to discredit you behind your back, so your accusation of
"trial by gossip" is unfounded.

As far as the rest of it goes, I recant my refusal to play your game
and I've posted a rather interesting circuit at:

news:Psnadk7pth8oevs7buf4a8qccuvepd3q9ok@4ax.com

Care to discuss it?
Reply to
John Fields

Seems awfully complex, even before you implement the clock and floating power supply.

--

John Larkin, President       Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
Reply to
John Larkin
[snip]

Your link doesn't function. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

It is a reference to a news article. You should know other ways to hunt up said article on your news server.

The point lost here (apparently), is that he posted a circuit in Usenet at some time in the past and referenced it here.

And the JL twerp can't stop lying about him and others. This group is probably worse then the kook group after 12 years of "Larkin Gone Loony".

Reply to
TheGlimmerMan

OK, say something about JF's circuit.

--

John Larkin, President       Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
Reply to
John Larkin 

--
"Pretty accurate zero-crossing detector, just for fun." on abse.
Reply to
John Fields

That's what I thought it was. For some reason Agent has lost it and can't re-find.

I did save it as a .asc ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson 

--
Oh, well...
Reply to
John Fields

I'd suspect it to have some logic hazards, too. There are a couple of race conditions associated with the asynchronous comparator output entering the clocked logic through multiple paths.

--

John Larkin, President
Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation
Reply to
John Larkin

Can we see that circuit in ascii or the LTSpice listing or image shack somewhere?

Reply to
Fred Bloggs

ed text -

There are such things as master-slave comparator logic that completely eliminate race hazards.

Reply to
Fred Bloggs

the ltspice listing isn't very useful unless you get the libraries for counters,flipflop,nand and nor gates that came with it

anyways the OP intended to connect the zcd to an mcu, so anything more that something that can provide a trigger at a repeatable place in the sinewave, connected to a timer pin is really redundant

-Lasse

Reply to
langwadt

text -

How does that work?

The general rule about bringing an async signal into a clocked state machine is: synchronize the async signal to the clock in one place only, and bring that into the synchronous domain on one wire only. If you're really paranoid about metastability (which you should be with CD4000 stuff) use a dual-rank synchronizer.

If you violate that rule, it may work, but it becomes a huge effort to prove that it is safe.

--

John Larkin, President
Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation
Reply to
John Larkin 

--
The DC supply is V2 and it isn't floating at all, its negative side
being connected to ground and its positive side to Vcc.

The FWB is a sensor, not a supply, _is_ floating, (except for the 1g
resistor which LTspice needs in there in order to keep from throwing
up) and full-wave rectifies the floating mains represented by V1.

As for the "hazardous" race conditions, you must have missed that the
logic is driven by a two-phase clock which eliminates the races.

With that in mind, can you provide a timing diagram which proves your
point?
Reply to
John Fields 

--
In addition to the .asc, there are five .asy files and one .lib file
that you'll need to run the sim.

Since you weren't able to download them from abse, I'll email you
copies/
Reply to
John Fields

no matter what point you define as ground you'll still need a supply for the logic and it needs to be floating with regards to the stuff on the other side of the isolator

-Lasse

Reply to
langwadt

Everyone! Please continue breathing. There will be no response from Larkin except denigration and platitudes. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

All this talk about zero crossing detection, when a simple monostable type transistor pair circuit floating on the load device coupled with a photo circuit will serve as a zero cross detector and trigger.

That will insure that the device gets switched on only at the base and not any other time, regardless of where the sine is when the control trigger comes on.. It just needs to be on at the time when it swings through the axes.

Jamie

Reply to
Jamie

I downloaded the whole deal when it first appeared. The only confusion was the call to a Message-ID that Agent croaked on. Still don't know why. It always worked in the past, even on stuff it has to search for on-line. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

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