help pls...measuring AC frequency

[news-server.mn.rr.com]

This may be way too easy for you folks, but it would sure help me if someone
could answer.

I have a generator at an off-grid cabin hooked to a charger/inverter system
with 4 golf cart batteries. Works great to get 110v 24x7 only running the
generator ~2 hours daily.

Recently I upgraded my charger to a unit that has tighter power quality
tolerances.....specifically, it requires input AC voltage to be within 5v of
120v and frequency to be within 5Hz of 60Hz. The diagnostic on the charger
is telling me my generator has "bad AC" and is putting out 67Hz.

I have the generator at home now and want to measure frequency with my
multimeter....it is a Radio Shack 22-812. Bear with me now please, because
I don't understand electricity and electronics all that well. The user
instruction manual is very cryptic but I think that I set the main control
on one of the V (voltage) settings, probe the 110v outlet with red on hot
and black on neutral (not on ground, right?), and then after I get the
voltage reading, I press the Hz/Duty/Width button to cycle thru the various
settings, specifically here to get the frequency from the Hz option.

Does this seem right? There is also another option on the main (round)
control that says Logic/Hz, but I am reading an ambiguous comment in another
place in the manual that that setting should not be used for any circuit
with significant voltage (maybe that option is for getting frequencies say
off of an audio signal, or ?).

I have searched all over the internet to try to understand how to make this
measurement, but I ham having problems figuring it out. Can someone help?

Also, on the main control, for the voltage options, there are two given.
One says 1) dBm~V, while the other says 2) C/F_V, where in the latter, the _
is a flat bar with three dashes below. One place in the manual says these
options mean 1) "selects AC voltage measurement in dBm or volts", and 2)
displays temperature and measures DC volts. It seems quite obvious that if
I want to measure AC frequency I should select option 1), but in the part of
the manual that advises the procedure for "measuring AC voltage frequency",
the intro says "The meter can measure the frequency of an AC voltage, with
or without a DC source bias", and then in the first subpoint it says "If you
are measuring AC voltage with a DC source bias, set the function selector to
dBm~V. Otherwise, set the function selector to C/F_V". (it then proceeds
to advise to press the Hz/Duty/Width button, etc). This seems backwards to
me, like a typo. I don't really know what "DC source bias" means, but I
think 110v power from my gene or from my outlets in my home should not be
"DC source bias". IE, I SHOULD use the dBm~V function, right?

I hope someone here can help me so I don't blow up my new $70 multimeter.

Thanks,

Tim

 

[Phil Allison]

"news-server.mn.rr.com"

Recently I upgraded my charger to a unit that has tighter power quality
tolerances.....specifically, it requires input AC voltage to be within 5v
of 120v and frequency to be within 5Hz of 60Hz. The diagnostic on the
charger is telling me my generator has "bad AC" and is putting out 67Hz.

I have the generator at home now and want to measure frequency with my
multimeter....

** Just connect a 120 volt electric clock/clock radio ( digital or normal )
to the gene.

Time keeping will only be good if the gene is spot on 60 Hz.





......... Phil

 

[Le Chaud Lapin]

"news-server.mn.rr.com"

** Just connect a 120 volt electric clock/clock radio ( digital or normal )
to the gene.

Time keeping will only be good if the gene is spot on 60 Hz.

If only that were true. Clock radios regard power sources as power
sources. A digital clock will take a dirty AC source and convert it to
a nice, clean DC signal.

To the OP:

The comment about Logic/Hz must be heeded. That is for logic circuits,
nominally for 5V. If you pick a voltage too high, depending on the
meter, there is strong chance that you will fry the fuse inside.

The dBm normally means decibels-over-milliwatt. Not sure what it means
in your context.

The DC bias feature is for signals that are sine waves whose average
value is not zero, is normally the case. So you might have a signal
that is a sign wave with +5V--5V peak-to-peak, riding on a DC voltage
of 50V, so that when you look at it on oscilloscope, the combined
voltage still looks like a sine wave, but never rises above 55V, and
never drops below 45V. The DC bias switch is a way of telling the
meter to ignore the DC offset - what you're really interested in is the
AC wave. As you guessed, your generator has a zero DC-biased (normal,
no frills sine wave). The C is for Celsius (as you probably guessed
after writing post) and F is for Fahrenheit.

Not sure what kind of generator you have, but many of them allow you
access to the governor (speed control). Tweaking it a little bit would
slow the engine down a few cycles to get you within range of 60Hz.
[Not sure why they don't simply build an electronic feedback system to
keep the generator at 60Hz.]

-Le Chaud Lapin-

 

[Phil Allison]

"Le Shithead LAIR "

If only that were true.

** Shame how it IS true - you fucking TENTH wit.

Clock radios regard power sources as power
sources. A digital clock will take a dirty AC source and convert it to
a nice, clean DC signal.

** ABSOLUTE BOLLOCKS !!!!!!!!!!!!!!

Go look up how typical clock radio ICs operate.

A sample of the AC supply voltage is fed to the clock chip for timing
purposes - if and when the AC supply fails, a simple ( not very
accurate) RC oscillator takes over until the AC supply is restored.

Normal AC clocks use a synchronous motor.

Wanna doubt that too - asshole ??





........ Phil

 

[mkaras]

"Le Shithead LAIR "





** Shame how it IS true - you fucking TENTH wit.






** ABSOLUTE BOLLOCKS !!!!!!!!!!!!!!

Go look up how typical clock radio ICs operate.

A sample of the AC supply voltage is fed to the clock chip for timing
purposes - if and when the AC supply fails, a simple ( not very
accurate) RC oscillator takes over until the AC supply is restored.

Normal AC clocks use a synchronous motor.

Wanna doubt that too - asshole ??





....... Phil

Well Well Well.

Yesteryear clocks did often use the AC line frequency as the timing
source for the clock. In fact some chips even had a 50/60 Hz select
input so that the chips were useful in more parts of the world.

Today there are many more clock designs that use an IC chip connected
to a 32.768 KHz crystal. These designs often have both a backup battery
and get power from the AC line. However it is often also the case that
it is cheaper to produce products that use just batteries if the
product only offers a clock function.

- mkaras

 

[Phil Allison]

"mkaras" = shithead #2

Well Well Well.

** **** **** **** OFF IMBECILE .

Yesteryear clocks did often use the AC line frequency as the timing
source for the clock.

** BOLLOCKS - there is no " yesteryear " about it.

The AC supply is still ** by far ** the most accurate timing reference at
low cost for a mains powered clock.

Today there are many more clock designs that use an IC chip connected
to a 32.768 KHz crystal.

** Go NOTHING to do with the vast majority of AC powered clocks &
clock radios.

F U C K W I T !!!!






........ Phil

 

[[email protected]]

If only that were true. Clock radios regard power sources as power
sources. A digital clock will take a dirty AC source and convert it to
a nice, clean DC signal.

-Le Chaud Lapin-

That's odd; I've built several clocks based off the AC mains and they
are still accurate TO THE SECOND months later, using NIST as a
reference.

 

[Le Chaud Lapin]

That's odd; I've built several clocks based off the AC mains and they
are still accurate TO THE SECOND months later, using NIST as a
reference.

Yes, my error. You're both right, you and Phil.

-Le Lukewarm Lapin-

 

[Tom Bruhns]

Gad, Tim, I don't know what happened to answering your fairly
straightforward question.

Nice of Radio Shack to put the manual online as a PDF. Measuring
frequency is covered on Page 25-26. It's the section starting in the
middle of Page 26 that you want to follow. DO NOT use the "Logic/Hz"
setting of the function switch. That's for low voltages only. You
actually should be fine with EITHER the dBm/~V or the C/F/-V setting.
Since you probably already want to test the AC voltage, just pick the
dBm/~V setting. After measuring the voltage, press the Hz/Duty/Width
button until "Hz" appears (I assume on the right side of the display,
but they don't show any display pix in the manual!). Connect the leads
to the generator. It's not clear if the meter is capable of resolving
less than one Hz; you may see 67Hz, or 67.3Hz, depending. I assume it
can resolve down to 1Hz at least, though.

Looks like a pretty capable meter. Maybe it will be incentive for you
to learn more about 'lectronics! It can be enjoyable, if you don't let
the grouches get to you.

Cheers,
Tom

 

[Rich Grise]

I have a generator at an off-grid cabin hooked to a charger/inverter system
with 4 golf cart batteries. Works great to get 110v 24x7 only running the
generator ~2 hours daily.

Recently I upgraded my charger to a unit that has tighter power quality
tolerances.....specifically, it requires input AC voltage to be within 5v of
120v and frequency to be within 5Hz of 60Hz. The diagnostic on the charger
is telling me my generator has "bad AC" and is putting out 67Hz.

I have the generator at home now and want to measure frequency with my
multimeter....it is a Radio Shack 22-812. Bear with me now please, because
I don't understand electricity and electronics all that well. The user
instruction manual is very cryptic but I think that I set the main control
on one of the V (voltage) settings, probe the 110v outlet with red on hot
and black on neutral (not on ground, right?), and then after I get the
voltage reading, I press the Hz/Duty/Width button to cycle thru the various
settings, specifically here to get the frequency from the Hz option.

Does this seem right?

Yup. I also concur with Tom Bruhns - don't let the boneheads get you down.
Actually, this can be a pretty harsh NG, so I've gone ahead and
crossposted this to s.e.basics, with followups to there; that's really
where this question belongs, and the people who frequent there don't
denigrate newcomers - they're very welcome, and it's a very helpful group.
Some of the posters in s.e.design participate there as well, when they're
sober. ;-P

Anyway, I've left the rest of the post for the benefit of s.e.basics:

There is also another option on the main (round)
control that says Logic/Hz, but I am reading an ambiguous comment in another
place in the manual that that setting should not be used for any circuit
with significant voltage (maybe that option is for getting frequencies say
off of an audio signal, or ?).

I have searched all over the internet to try to understand how to make this
measurement, but I ham having problems figuring it out. Can someone help?

Also, on the main control, for the voltage options, there are two given.
One says 1) dBm~V, while the other says 2) C/F_V, where in the latter, the _
is a flat bar with three dashes below. One place in the manual says these
options mean 1) "selects AC voltage measurement in dBm or volts", and 2)
displays temperature and measures DC volts. It seems quite obvious that if
I want to measure AC frequency I should select option 1), but in the part of
the manual that advises the procedure for "measuring AC voltage frequency",
the intro says "The meter can measure the frequency of an AC voltage, with
or without a DC source bias", and then in the first subpoint it says "If you
are measuring AC voltage with a DC source bias, set the function selector to
dBm~V. Otherwise, set the function selector to C/F_V". (it then proceeds
to advise to press the Hz/Duty/Width button, etc). This seems backwards to
me, like a typo. I don't really know what "DC source bias" means, but I
think 110v power from my gene or from my outlets in my home should not be
"DC source bias". IE, I SHOULD use the dBm~V function, right?

I hope someone here can help me so I don't blow up my new $70 multimeter.

Thanks,

Tim

Cheers!
Rich

 

[JoeBloe]

A digital clock will take a dirty AC source and convert it to



** ABSOLUTE BOLLOCKS !!!!!!!!!!!!!!

Go look up how typical clock radio ICs operate.

A sample of the AC supply voltage is fed to the clock chip for timing
purposes - if and when the AC supply fails, a simple ( not very
accurate) RC oscillator takes over until the AC supply is restored.

Normal AC clocks use a synchronous motor.

He said digital, dumbshit.

Nearly ALL electrically powered "clocks" these days have the same
precision crystal stepping them at 32,768, which is exactly 2 to the
15th power.

All that is then needed is 15 divide by two stages. All watches
that are not 100% mechanical, and all battery operated or AC operated
"digital" clocks use it as well.

Have you ever made a post where you aren't insulting someone?

That goes for the retarded topic header title changes as well. Did
you ever mature beyond the mental age of twelve?

 

[JoeBloe]

The AC supply is still ** by far ** the most accurate timing reference at
low cost for a mains powered clock.

You're an idiot. I can buy AC powered clocks at the dollar store
that have quartz timebase circuits in them.

 

[JoeBloe]

** Go NOTHING to do with the vast majority of AC powered clocks &
clock radios.

F U C K W I T !!!!

"Go NOTHING"??? What the **** is that, retard boy? Is that you
waving to us as you go?

Go, NOTHING, GO!

Most clocks today, even AC powered jobs have crystals in them.
Maybe in your half assed backwards neck-o-tha' woods they don't, but
'round here they surely do. In fact, it is harder to find an AC
powered wall clock out here. Most are single cell operated, QUARTZ
timed, bob-o-loid designs where the second hand is toggled by a small,
swinging bar that moves through a dual solenoid actuator. The quartz
crystal times the pulses sent to the solenoids.

 

[Jim Thompson]

"Go NOTHING"??? What the **** is that, retard boy? Is that you
waving to us as you go?

Go, NOTHING, GO!

Most clocks today, even AC powered jobs have crystals in them.
Maybe in your half assed backwards neck-o-tha' woods they don't, but
'round here they surely do. In fact, it is harder to find an AC
powered wall clock out here. Most are single cell operated, QUARTZ
timed, bob-o-loid designs where the second hand is toggled by a small,
swinging bar that moves through a dual solenoid actuator. The quartz
crystal times the pulses sent to the solenoids.

If you didn't reply to Phyllis we'd all be spared this nonsense ;-)

...Jim Thompson

 

[Eeyore]

He said digital, dumbshit.

Nearly ALL electrically powered "clocks" these days have the same
precision crystal stepping them at 32,768, which is exactly 2 to the
15th power.

All that is then needed is 15 divide by two stages. All watches
that are not 100% mechanical, and all battery operated or AC operated
"digital" clocks use it as well.

Have you ever made a post where you aren't insulting someone?

That goes for the retarded topic header title changes as well. Did
you ever mature beyond the mental age of twelve?

Phil is right actually.

The ac mains beats a cheap crystal for long term timekeeping any day.

Graham

 

[Eeyore]

"Go NOTHING"??? What the **** is that, retard boy? Is that you
waving to us as you go?

Typo lames seem to be your speciality.

Go, NOTHING, GO!

Most clocks today, even AC powered jobs have crystals in them.
Maybe in your half assed backwards neck-o-tha' woods they don't, but
'round here they surely do. In fact, it is harder to find an AC
powered wall clock out here. Most are single cell operated, QUARTZ
timed, bob-o-loid designs where the second hand is toggled by a small,
swinging bar that moves through a dual solenoid actuator. The quartz
crystal times the pulses sent to the solenoids.

So they aren't AC powered clocks then are they ?

Graham

 

[Phil Allison]

"Joe Bloe It Out His Arse "

He said digital, dumbshit.

** He was replying to MY use of that same word.

Do try to follow the thread - Mr Anonymous Fuckhead.

Nearly ALL electrically powered "clocks" these days have the same
precision crystal stepping them at 32,768, which is exactly 2 to the
15th power.

** Clocks are not the issue in point.

The actual comment was:

" a 120 volt electric clock/clock radio ( digital or normal ) "

All that is then needed is 15 divide by two stages. All watches
that are not 100% mechanical, and all battery operated or AC operated
"digital" clocks use it as well.

** ABSOLUTE BOLLOCKS !!!

Go look up the data for the very popular TMS3450 NL or LM8560 " digital
clock radio " ICs

No crystals in sight.

A 50 /60 Hz supply is as the reference.

Cos it is far more accurate than a watch crystal.

Have you ever made a post where you aren't insulting someone?

** I make a special effort to insult congenital liars and fools like YOU
to the max.

Frankly, I would prefer to see you all hanged by the balls.





......... Phil

 

[JoeBloe]

If you didn't reply to Phyllis we'd all be spared this nonsense ;-)

...Jim Thompson

You're right!

You could have at least chimed in on the topic though.

 

[Phil Allison]

"Joe Blows It Out His Arse Fuckhead "

You're an idiot. I can buy AC powered clocks at the dollar store
that have quartz timebase circuits in them.

** ROTFLMAO !!

Damn shame how the AC supply frequency is far more accurate than a watch
crystal.


Now **** OFF you know nothing pile of SHIT !!!




....... Phil

 

[Phil Allison]

"Joe Blows It Out His Arse MORON "

Most clocks today,

** Clocks are not the issue in point.

The actual comment was:

" a 120 volt electric clock/clock radio ( digital or normal ) "

All that is then needed is 15 divide by two stages. All watches
that are not 100% mechanical, and all battery operated or AC operated
"digital" clocks use it as well.

** ABSOLUTE BOLLOCKS !!!

Go look up the data for the very popular TMS3450 NL or LM8560 " digital
clock radio " ICs

No crystals in sight.

A 50 /60 Hz supply is as the reference.

Cos it is far more accurate than a watch crystal.

Have you ever made a post where you aren't insulting someone?

** I make a special effort to insult congenital liars and fools like YOU
to the max.

Frankly, I would prefer to see you all hanged by the balls.




......... Phil