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Good presentation!

Iron

analog and digital

Iron

measure power for myself

Iron

I'm interested in digital 

I will be measuring power for myself

I think 1% would be a good value

@moderator - for myself

Iron

Great to have access to the recorded sessions

Iron

Missed the live lecture

Iron

Thank for informative presentation

Total power, voltage, current, phase

I feel comfortable with either digital or analog design.

Iron

1 or 2% accuracy is adequate.

Power for myself.

Iron

Thanks Bill. Very informative session.

Iron

I have predisposition towards digital computation for my applications

Iron

I mainly use digital measurements

Iron

I'm measuring power for myself

Iron

Accuracy I'm looking for in my measurements : 0,5% - 2%

Iron

Archived session today

 

Iron

Posting off bill and ed see you.

Iron

@rswanson, good memory. 400Hz power also made the soldering iron get even hotter! The patrol aircraft I worked on at the time had outlets for appliances and test equipment.

Iron

Another benifit I remember for 3 phase power is that it creates a rotating magnetic field inside of motors by having 3 windings. This is good for starting a motor and setting its direction of rotation. Using single phase power, motors have to use some form of phase shifter to do the same thing.  Also with 3 phase power, the total power  is distributed over three wires instead of one or two, and therefore smaller wire is needed.

Iron

Bill and Jojo, I just happened to glance at the chat before logging out.

I was involved with aircraft work years ago. My instructors like to point out that 400Hz, 3 phase power was nearly DC when it came out of the rectifier. Smaller filter caps, redundant power supply if 1 phase fails were tsome of the benifits.

Iron

OK, we're getting ready here to go on hiatus until tomorrow. Thanks to all for attending, and live chatting.

Blogger

Jojo: it's hard to explain in a few sentences, a good but brief reference is

http://en.wikipedia.org/wiki/Three-phase_electric_power. It';s been known for about 100 years, those early power guys were pretty smart.

Blogger
Bill thank you for today's lecture.
Iron

Bill: I'm not a power guy, but I would like to understand better the rational why 3-phase is more efficient than single phase. Is it because the load can be distributed better in 3-phase while single phase takes all the brunt?

Iron

MrE: a DSP can do the job, for sure--but the component and dissipation cost may be too high for the application, depends on specifics of the project.

Blogger

MPEDRAZA--you may nbot need digital--but if you want to capture, retain, an dfurther analyze, you will. Question really is at what point in the signal chain to you go digital: at the front end, or further along the chain, after the analog calculation?

Blogger

@rswanson: MSP430 is a large family of TI digital signal processors, but I am not sure what the different suffixes signify. Maybe peruse www.ti.com to investigate.

Iron

I am interested in the analog mainly in RMS and avaerage. But why is digital important as well as the Analog type?

Iron

Davet22: there's also "instantaneous power". So you have to check the definitions that your industry segment uses for each.

Blogger

thank you for today's lecture

Iron

Davec3000: those ICs can be good options, yes. But you still have to think about what you are trying to measure. It's like using an "average": usually a good thing, but by definition, "average" obscures detaisl--and that may be very good, or very bad, for the situation.

Blogger

Thanks Bill. Appreciate these courses.

Iron

Apparent/Real power has to do with power factor, and current/voltage phase relationship. Not sure what "true power" is, unless it's another term for real power?

Blogger

Thanks Bill, time to earn my keep. See you and all tomorrow.

Iron

Bill, do you have any comments on the Power Measurement IC's.  For example the Cirrus 5484 for 50/60 hz AC.  That would seem to simplify the design considerably, making it more of an interface question.

 

Iron

@DaveWR. I'm having difficulty finding data sheets on the controllers you mention (MSP430F57197 and
MSP43047197). Would you suggest some sources where I could look?

Iron

Bill, Think my post did not  get through - repeating: What is the proper definition of "True Power" vs. "Real" and "Apparent" power? Thanks.

Iron

we'll be here a few more minutes, if you are still formulating your comment or question, or even your answer to another comment/question.

Blogger

cmeadows6959--then I suggest you take the rest of the day off, quit while you are ahead for the day!

Blogger

i learn something new everyday. thanks Bill.

That makes sense. As the late, lengendary Jim Williams often said "sometimes a good op amp can do the work of 1000 gates or lines of code."

Blogger

The audio was poor. I missed the first 10 minutes. I had to try various browsers before it came on. 10 minutes of music before would be nice to get everything debugged. I need to do this everyday.

Iron

Yes Bill, analog can be a simple solution. I tend to try compressing most operations into a uC with analog front-end to condition or pre-process. That would be the hybrid approach you mention. Hardware reuse is easier for me when a uC is used instead of a dedicated circuit.

Iron

Or use a hybrid (analog+digital analysis) approach. Again, it depends on the question(s) you are tyring to answer re power, and what sort of details you are looking for.

Blogger

danlafleur--IMO, analog approach is usually lower cost, and smaller--unless you have ADC and CPU resources to spare.

Blogger

Intermitten audio for me, and today I'm viewing from home with a great internet connection and no corporate spyware running in the background.

Iron

Using Digital due to calculation and accuracy requirements -- better than 1% -- so using TI MSP43047197 SOC -- since it has 14 Bit ADC etc. Regulatory approval -- so not much choice for cumulative energy use. Complicated -- but that's the answer.

Iron

I had to keep restarting the browswer until the audio started working.

 

Iron

trouble with audio today

Iron

Sorry about the audio problems, I believe (hope) the archived audio is OK.

Blogger

"Predisposition" makes me nervous.  It's likened to answering the design question before the entire question is asked. :)

low cost and small physical size makes me try a digital solution first. 

Iron

did the audio work for everyone?

Iron

No predisposition, it depends on the application.

Iron

Thanks Bill. Had troubles with audio today...but otherwise enjoyed.

Iron

Analog when possible. Simplier, cheaper.

Iron

Thanks Bill and Rich.

Iron

It depends on the requirement.

I use Digital measurement.

Iron

Thanks everyone. The final question: Do you have a predisposition towards analog or digital computation for your application?

Blogger

prefer digital most cases due to simplicity & number of choices

Iron

Analog front end, then digitize the result, is often a better way than going digital at the earlier stages. But of course, "it depends".

Blogger

Mr E--you always need more headroom/cushion in these things, and the extra cost of thsoe bits is minimal these days

Blogger

No I don't will use whichever is a better fit for the project being done.

Iron

I tend to go analog first, then digital for measurement solutions.

Iron

For subsequent use it must be digital

Silver

@bicyclebill: Second bullet on slide 3 suggests that 12 bits resolution (1 part in 4096) are required to digitize an analog value to 1% full scale. Is that what is meant? If it is, why not 7 bits (1 part in 128, which is approximately 1%)?

Iron

Thanks Bill great program...

Iron

Costwise of different solutions?

Iron

Looks like the audio is a bust today

Iron

analog is also quiet, no digital noise.

Iron

Do you have a good source for the software?

Audio problems - both IE and Chrome!

 

Iron

The audio problems with this web are bad, good program bad audio.

Measuring power for internal test.

Iron

Reloaded agin, it worked for a few seconds and then it stopped again

Iron

Ola from Midland TX

Iron

had to hit the button my self to get the audio, why does it not auto start when it appears on the screen?

 

Iron

Reloaded, then it said blogtalk radio, and then it stopped

Iron

Reloading browser did the trick. Thanks.

Iron

measuring power for battery supply applications. minimum power consumption/maximize time on battery

Iron

To meet regulatory or compliance standards

Iron

No audio; measuring power for myself

Iron

If you are not getting audio, please reload your browser.

Blogger

Fired up paused, good audio now.

Iron

accuracy varies; measuring dc and ac for myself

Iron

Project I am on is <1% accuracy, 3Phase AC -- must get regulatory approval -- assuming I do it. ;-)

Iron

Question 2: Are you measuring power for yourself, or to meet regulatory or compliance standards?

Blogger

Hello from Sandersville, Georgia.

 

Iron

measuring power for self, for compliance, for comparison with grid utility meter

Iron

Question 1: What approximate accuracy are you looking for?

Blogger

Either AC or DC, any voltage.   But I'm talking about a DVM voltage check.   :)

Hello, first time to be here. is the presentation started? i have no audio. thanks.

Iron

1 to 2 percent. Myself

Iron

Good afternoon Bill.

Iron

neon lamp across the ac line fuse, or even across a high voltage DC supply works OK. both sides of the lamp glow for AC, one side only for DC.

Iron

What type fuse, AC, DC low voltage, high?

Iron

Good afternoon folks.

Iron

Those neon-bulb days are gone....

Blogger

Rick Here from Corona California

Iron

that is right, get the slides.

 

Iron

Back in the "old days" putting a neon lamp across the line fuse made a pretty good blown fuse detector.

Iron

Bill is armed and ready.

Blogger

Heyi All from Texas

 

Iron

Hello from sunny Arizona

Silver

Sorry about the font size.   :)

Hi All from California

Iron

I'd like to see a poll: when checking failed fuses, is it acceptable to DVM across the fuse verses to earth/ground/common?   I check to E/G/C, but the topic can bring heated discussions!   (Temps here are expected to drop 25+ in 45 minutes or less!)   :)

Good morning everyone from CA

Iron

I think Sandy will be pretty direct west of Melbourne and Daytona Saturday.

Iron

The article says landfall at New Jersey on Tuesday.

Iron

Will the storm reach Daytona by Sunday?

Iron

I just saw a news headline about the "FrankenStorm", wow!

Iron

Hello from Melbourne Beach, FL. Surf is UP! (Sandy)

Iron

Hello from Boston, hoping Hurricane Sandy doesn't make her way up here!

 

Iron

Accuracy is something I'll touch on today--it's the old story: how much do you need? What are you trying to find out,anyway? And how much $ can you afford?

Blogger

Your slides mention 12Bit accuracy for measurement. I am currently testing TI MSP430F57197 (SOC) for 3 Phase -- it has 7 X 16 Bit Ganged (simultaneous reading) ADC -- others in this lne have up to 24 bit ADC -- fwiw -- I have not checked other lines.

fwiw

 

Iron

We do talk fast--in fact, we have to make a deliberate effort to slow it down!

Blogger

Us Birds are getting our nests in order strengthened hardened for the blow thats heading our way next week! 

Iron

Hello from sunny SE Lake Simcoe. Ontario Canada. (It really is sunny and warm today... Talk fast :-) )

Iron

Howdy folks!!!   :)  

early worm gets eaten by the bird!

Iron

Hello to all you "early birds"--thanks for signing in--Bill

Blogger

Good day everyone. Remember to download the slides from the link above.

Blogger

Hello all from Edmonton, AB

Iron

I want a t-shirt.

Do you need S & H

to central Alaska?

Iron

Hello everyone

Thanks Bill for the level of simplicity that you are able to bring to this important topic.

Go GIANT !!!!!

Jarnail (Calgary Alberta Canada)

 

Jarnail

Iron

Hello From San Jose, CA

it's 54°F and a High of 67°F Cloudy in the morning and Sunny in the afternoon.

"GO GIANTS !!!"

WS Standing:

GIANTS (1)

Tigers (0)

Iron

Hello, from Richmond BC Canada

Iron

good day from snowy Holladay UT

 

Iron

With you all again from Huntsville.  I have enjoyed the discussions.  Thanks

Iron

Hello from McHenry, IL

Iron

Hey!; the sun is shinning here in central NY.

Iron
Hello from Mesquite, NV
Iron

Hello from San Diego.

Iron

Ready for today's session

Iron

Looking forward to attending to today's lecture. sound very interesting

 

Iron


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