Extech MM560 - Micronta 22-167 Shootout

[MassiveProng]

Shorting the probes has no effect. :-( Oddly enough, it only does then
when you have AC+DC (which was apparently the default) or just AC selected.
If you select DC only then it seems fine. OTOH, if you select only AC
current, it does the countdown thing, only slightly differently (it takes
the same amount of time to get down near zero, it just updates the display
several times/second instead of once every couple of seconds). Strange. I
wish someone else had one and could tell me there experience.

On a uA scale on AC, it could easily be induced into it from local
sources.

See if it does it without the leads attached. If not, try it with
the leads twisted.

Maybe you have a little electric eel in you.

 

[David L. Jones]

On a uA scale on AC, it could easily be induced into it from local
sources.

See if it does it without the leads attached. If not, try it with
the leads twisted.

Maybe you have a little electric eel in you.

Then you must have one too.
Your beloved Protec 506 does a similar thing without the leads, uA and
mA scale.
It's the RMS converter settling.

Dave

 

[Robert Baer]

They certainly didn't make me unhappy by that. Now Mouser on the other
hand........... e-mail to tech support at 11:00am yesterday, not a peep. I
guess they aren't much on e-mail. I'm going to go ahead and keep it for
now, at least until I have reason to suspect that something really is wrong
with it.




Sure does give really slow updates (seconds between each one). I'm glad I
don't have to use it unless I need it.




I looked around some of the cal sites and in some places it's one of the
very few radio shack models they will even look at. This seems to be an
almost exact copy of it:
http://www.tequipment.net/EZDigitalKD3220.asp. The pc board has KD-3200C
stamped on it. Awful cheap now compared to when I bought mine.

I sure wish my scope would hurry up and get here.

Mouser has an 800 number and they have always been courteous and helpful.
And it did not seem to make a difference whether i wanted to return
*one* item or order 70,000.

 

[Anthony Fremont]

I like that it uses the same jack for V/ohms and uA/mA, no lead
swapping.

Right, just fuses. ;-)

What's the build quality of the Extech like inside?
Photos?

I haven't opened it up yet, since it had the batter installed already. I'll
try to do it before the weekend is out. Exterior is good, the backlight is
pretty bad. Not sure what they were thinking on that, maybe it's a power
consumption thing. Instead of being edge lit, it seems to have four leds
behind the panel. Maybe it's an illusion.

Was that the 1000 series Rigol ?

Yup, that would be it. The DS-1102C. I passed on the logic analyzer
function, but it seemed to be a decent one. I'm going to wait for an
external LA that decodes protocols. What do you think of this for a beater?
Nice big 8" screen with full VGA 640x480:
http://www.saelig.com/miva/merchant.mvc?Screen=PROD&Product_Code=PSSA002&Category_Code=
It seriously looks like allot of these scopes share allot of the same
hardware technology internally, regardless of the name. Even the software
looks and functions in suspiciously similar ways between brands. These
scopes are made by Owon: http://www.owon.com.cn/eng/index.asp Too much
engrish in the manual though, and ugly overcompressed diagrams and images.
Too bad, cuz with a full VGA display, it'd pretty much have to look nice and
sharp. They shouldn't have chinced like that on their manual. The battery
option is only like $75US.

 

[Anthony Fremont]

Anthony Fremont wrote:

Mouser has an 800 number and they have always been courteous and
helpful. And it did not seem to make a difference whether i wanted
to return *one* item or order 70,000.

I'm sure that's true, I've bought stuff from them for over ten years. I'll
let them slide this time on it. ;-)

 

[Anthony Fremont]

On a uA scale on AC, it could easily be induced into it from local
sources.

See if it does it without the leads attached. If not, try it with
the leads twisted.

It does it with no leads. Any time it is first placed in one of the AC or
RMS modes, it does this. What seems so strange is that switching from mA to
uA doesn't change what you see in the display, it just keeps doing it's
thang counting downwards. The general consensus is that the true RMS
converter is to blame here and that this is normal behavior. David says his
Fluke takes about 30 seconds to settle down. This one will keep going for
about two minutes before it really gets "stable", but after the first 30
seconds or so it's within about 20 counts of its resting point. The meter
seems to work fine, at least it's in agreement with my micronta. ;-)

 

[MassiveProng]

Then you must have one too.
Your beloved Protec 506 does a similar thing without the leads, uA and
mA scale.
It's the RMS converter settling.

Some meters beep alarm when in current mode without leads.

 

[MassiveProng]

It does it with no leads. Any time it is first placed in one of the AC or
RMS modes, it does this.

Another poster's claim about the RMS circuitry seems true then. I
don't think it is a heating then as he said though. It is simply a
settling resolve at that delicate scale. Evidenced also by the fact
that it repeats even with great immediacy of a power/setting cycle.

Greater scales likely do it as well, only in mere milliseconds.

 

[MassiveProng]

What seems so strange is that switching from mA to
uA doesn't change what you see in the display, it just keeps doing it's
thang counting downwards. The general consensus is that the true RMS
converter is to blame here and that this is normal behavior. David says his
Fluke takes about 30 seconds to settle down.

Does it do so WHILE actually attempting to take a reading? As in, if
you look at some known current level right after a switch to that
scale...

It will either float down, or read the known value. It might just
not like resolving the RMS value for ZERO. :-]

 

[Anthony Fremont]

On 8 Mar 2007 16:05:55 -0800, "David L. Jones" <[email protected]>

Some meters beep alarm when in current mode without leads.

This one gets all upset if you have the red lead in a current measurement
hole, but turn the dial to voltage or resistance settings. It doesn't seem
to care about the other way. I guess it's protected and it figures that the
user will figure out why they aren't getting a reading.

 

[Anthony Fremont]

Does it do so WHILE actually attempting to take a reading? As in, if
you look at some known current level right after a switch to that
scale...

At least when the current that you measure is larger than the count, it
doesn't seem to be affecting anything. IOW, you won't see 1.50mA ticking
downward continuously.

It will either float down, or read the known value. It might just
not like resolving the RMS value for ZERO. :-]

It seems to act like it's following a charge or discharge curve. It counts
way fast at first and then keeps slowing down. I never really need RMS
values anyhow, so I can just turn it off. What does your Protek do when you
first put it in an RMS mode? Does it need a little settling time?

 

[David L. Jones]

@nowhere.com> Gave us:

Does it do so WHILE actually attempting to take a reading? As in, if
you look at some known current level right after a switch to that
scale...

At least when the current that you measure is larger than the count, it
doesn't seem to be affecting anything. IOW, you won't see 1.50mA ticking
downward continuously.

It will either float down, or read the known value. It might just
not like resolving the RMS value for ZERO. :-]

It seems to act like it's following a charge or discharge curve. It counts
way fast at first and then keeps slowing down. I never really need RMS
values anyhow, so I can just turn it off. What does your Protek do when you
first put it in an RMS mode? Does it need a little settling time?

As I mentioned in another post, the Protek 506 does the same thing,
takes about 30 seconds to settle down to zero, it does not have an
offset though.

Your Extech has switchable True RMS mode? If so that would be the
first meter I've seen with such a nice function!

Dave

 

[MassiveProng]

It seems to act like it's following a charge or discharge curve. It counts
way fast at first and then keeps slowing down. I never really need RMS
values anyhow, so I can just turn it off. What does your Protek do when you
first put it in an RMS mode? Does it need a little settling time?

I think it is pretty cheap. Nowhere near as good or advanced as the
ex you have. This meter is like six years old. It is also very
basic. I said I only use it for easy stuff like automotive.

Just looked... It's pretty sad only 4000 count... yes, only 3 zeros!

I'm sure that its version of "RMS" is a "close approximation", not
anything worth relying on too heavily.

It says "True RMS", but back in the seventies, car stereo makers
made a lot of false claims too. :-] Bet it would fail on 15th order
harmonics.

On current, it says it has a 400uA range with 0.1uA resolution.

The thing I like is the data link capacity. For a cheap meter, I can
pump figures into a spreadsheet without doing double entry.

Still some pretty sad figures by today's standards.

My OLD HP still hits home runs with some of the best of them though.

 

[MassiveProng]

As I mentioned in another post, the Protek 506 does the same thing,
takes about 30 seconds to settle down to zero, it does not have an
offset though.

Your Extech has switchable True RMS mode? If so that would be the
first meter I've seen with such a nice function!

Yeah, he threw me with that one as mine is in that mode all the time.
Suck ass meter though, by any desirable spec seekers.

 

[Anthony Fremont]

As I mentioned in another post, the Protek 506 does the same thing,
takes about 30 seconds to settle down to zero, it does not have an
offset though.

Your Extech has switchable True RMS mode? If so that would be the
first meter I've seen with such a nice function!

Dave

 

[Anthony Fremont]

Your Extech has switchable True RMS mode? If so that would be the
first meter I've seen with such a nice function!

You can pick DC, AC or Both (I assume that's "both" is true RMS mode). When
in "both" mode, the display updates very slowly. The countdown effect
occurs even when using just plain old AC mode (current or voltage), but the
display updates several times/second instead. The "countdown" procedes at
it's own pace no matter what mode you choose. This only happens in AC or
"both" modes, not in any strictly DC mode.

 

[Anthony Fremont]

I think it is pretty cheap. Nowhere near as good or advanced as the
ex you have. This meter is like six years old. It is also very
basic. I said I only use it for easy stuff like automotive.

Just looked... It's pretty sad only 4000 count... yes, only 3 zeros!

My micronta is only 3200 counts. Was great back then.

I'm sure that its version of "RMS" is a "close approximation", not
anything worth relying on too heavily.

It says "True RMS", but back in the seventies, car stereo makers
made a lot of false claims too. :-] Bet it would fail on 15th order
harmonics.

And they stopped.....when??

On current, it says it has a 400uA range with 0.1uA resolution.

So far I'm really happy with the low current measurement ability. My
micronta would give me .1uA resolution, but it wouldn't lock onto anything
that was less than about 1uA. For example, at 600nA, the Micronta would
kinda shudder and occasaionally show a reading of .6 or .7, but most of the
time it would show -0 or some such. The Extech has no problems.

The thing I like is the data link capacity. For a cheap meter, I can
pump figures into a spreadsheet without doing double entry.

Yeah, the extech has a data output, but it costs $70 for the cable and
software. It's a purely optical connection so I guess that's good from a
safety standpoint. I'm going to try and see if I can decode the data coming
out the IR LED in the back......if my scope ever gets here.

Still some pretty sad figures by today's standards.

My OLD HP still hits home runs with some of the best of them though.

The HP has really nice specs and ebay has them at a reasonable price.
Tucker wants 750 for a refurb, can you believe that?

 

[David L. Jones]

You can pick DC, AC or Both (I assume that's "both" is true RMS mode). When
in "both" mode, the display updates very slowly. The countdown effect
occurs even when using just plain old AC mode (current or voltage), but the
display updates several times/second instead. The "countdown" procedes at
it's own pace no matter what mode you choose. This only happens in AC or
"both" modes, not in any strictly DC mode.

In that case then it's always True RMS just like every other meter. Oh
well.

I presume it's slower in dual display mode because it has to use the
same converter to alternate between direct DC measurement, and
measurement of the output from the true RMS converter.

Dave

 

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