Its no Fluke...

[Zad]

Sorry about the pun...

You know how Dave gets Fluke multimeters in now and then for test, and goes on about the quality of construction, the effort that has gone into their design and how, despite their price, they are great value for money? Well, I get sent a Fluke 233 to test (that is one of those with the removable display) and thought I would pit it against my trusty 20 year old Fluke 77. I was reasonably confident but, well, 20 years is a long time, components values do drift, and it has been rather used and abused. I don't want to give the game away, I owe that to the people who gave me the meter, but here is an example of one of the tests I performed:



Current and resistance ranges performed pretty much the same. I don't have an expensive lab reference standard to compare them (the above photo was from my lab PSU which isn't massively precise) but 0.1% difference over 20 years? Wow! Engineering that good is no fluke. I really can't imagine that many of these Chinese meters are going to behave like that.

[Time]

I love that remote display meter.

[Kiriakos-GR]

I have stop for years to debate over  who builds the DMM .. ( Nationality )

Robots does the job , no matter where they are located, or what color of paint they have on them.

The quality of parts , was an issue before 30 years or more ..

Today, there is lots of quality parts , and less reasons to use them ...

I got this item for 10 Euros ,  has high quality PCB gold plated !!
Has perfect manufacturing , all parts well placed , has fresh lead-free soldering,
has an high quality display.

And its just a Digital tacho meter  with Laser pointer .  

Do not be afraid ... its made in China , I bet that it will stay alive for more years than me.

http://www.1ce.com.cn/home/ce040_eng/product.asp?class=1&classname=DIGITAL%20TACHOMETER



 

[slburris]

I have two Fluke 6.5 digit bench meters from the 1980's and they
agree with each other within a few counts of the last digit generally
and also agree with my Fluke 87-V to within the limits of that meter,
so I have to say I'm quite impressed with how well these meters age.

I heard stories of Flukes years since their last calibration that are still
well within their specifications, but I have no way to confirm that.

Scott

[saturation]

There are several others at least on eevblog, I am one.  My 2c to slburris' input.

I haven't calibrated my Fluke 85-I since 1989.  I recently compared it against a calibrated voltage source.  I used an HP 3456A lab DVM to test it across all its Vdc ranges and its accurate to 0.04% Vdc, at worst.  At best it was 0.01%.  I also did these measurements across a continuous 2 hour timespan, to check for short term drift, and it was rock steady.  I also tracked an c1981 DMM I made as a kit that has a user adjustable calibration, rated at 0.1%, and found that it really was more 0.5% and only 0.1% at the 1V scale.  I was testing my Mastech power supply, and comparing its built in DVM the manual claims is 0.5%, well it ranged from 0.3%-4.0%.  Also, the value would drift 1 digit while the others were rock steady.

This stability isn't something you'll read on the advertising literature when comparing DMM.  Fluke also understate specs, Fluke 85-I is rated at 0.5%+1 digit across all Vdc ranges, actual is more ~10x better.

Unlike excellent competitors from Agilent or Gossen Metrawatt, some Fluke models such as the 80s series, are still made, almost the same, continuously, for 20+ years.  So there is a good chance you'll get a Fluke with a similar real long term stability, not just a lab tested 'accelerated aging' test.

Agilent has been in-out of the handheld DMM business, so there is inconsistency.  Gossen is closer to Fluke as competitor, quality wise, in hand held DMM.

I have two Fluke 6.5 digit bench meters from the 1980's and they
agree with each other within a few counts of the last digit generally
and also agree with my Fluke 87-V to within the limits of that meter,
so I have to say I'm quite impressed with how well these meters age.

I heard stories of Flukes years since their last calibration that are still
well within their specifications, but I have no way to confirm that.

Scott

[alm]

Agilent has been in-out of the DMM business, so there is inconsistency.  Gossen is closer to Fluke as competitor, quality wise, in hand held DMM.

I don't understand what you mean by this. If you're talking about DMM's in general, HP/Agilent has been making bench DMM's continuously since the seventies or so (when hand held DMM's were not/barely around). About hand held DMM's specifically, as far as I know, the current series is their first (although Escort might have some experience), so if you ignore the bench DMM's, I'd say that they are new to this market. HP may have made some obscure hand held DMM that didn't sell well in the eighties (pen type?).

The funny thing is that Fluke actually has been in-out of the bench DMM market. Between the 8505/6 and 8840/2 that were designed in the eighties, and the recent 8845/6, 8808 and 8508 series, they didn't make any real bench meter (except the 'Fluke HP 3458A' which is a HP 3458A + 1 resistor and the low-end Fluke 45 that was basically a Fluke 189 in a different box) for ten years or so.

[saturation]

You're right alm, I forgot to add handheld, so correction made.  It does look like Agilent'a handheld models are heavily Escort influenced, [for others unaware, a Taiwanese company purchased by Agilent in the early 2008, http://www.agilent.com/about/newsroom/presrel/2008/10jun-gp08008.html].

HP/Agilent has led the bench DMM arena for sometime.

Interesting opinion on DMM's future:

http://www.evaluationengineering.com/index.php/solutions/instrumentation/dmm-is-an-understatement.html

Agilent has been in-out of the DMM business, so there is inconsistency.  Gossen is closer to Fluke as competitor, quality wise, in hand held DMM.

I don't understand what you mean by this. If you're talking about DMM's in general, HP/Agilent has been making bench DMM's continuously since the seventies or so (when hand held DMM's were not/barely around). About hand held DMM's specifically, as far as I know, the current series is their first (although Escort might have some experience), so if you ignore the bench DMM's, I'd say that they are new to this market. HP may have made some obscure hand held DMM that didn't sell well in the eighties (pen type?).

The funny thing is that Fluke actually has been in-out of the bench DMM market. Between the 8505/6 and 8840/2 that were designed in the eighties, and the recent 8845/6, 8808 and 8508 series, they didn't make any real bench meter (except the 'Fluke HP 3458A' which is a HP 3458A + 1 resistor and the low-end Fluke 45 that was basically a Fluke 189 in a different box) for ten years or so.

[alm]

You're right alm, I forgot to add handheld, so correction made.  It does look like Agilent'a handheld models are heavily Escort influenced, [for others unaware, a Taiwanese company purchased by Agilent in the early 2008, http://www.agilent.com/about/newsroom/presrel/2008/10jun-gp08008.html].
http://www.evaluationengineering.com/index.php/solutions/instrumentation/dmm-is-an-understatement.html

So when was Agilent in the handheld business before the Escort acquisition? In-out suggest that they were in the business at some point, stopped selling handheld, and re-entered the business some time later. I'm not aware of any serious attempt to get into the handheld market before, but it's quite possible that I'm simply not aware of their previous handheld DMMs.

Interesting opinion on DMM's future:
http://www.evaluationengineering.com/index.php/solutions/instrumentation/dmm-is-an-understatement.html

Not that surprising, every manufacturer says their products are the future. NI says that the monolithic instrument is dead (and have been saying this for how long?). There's even a company preferring VXI/PXI over LXI (seems kinda backwards). But a neat overview of some DMM features, thanks for the link.

[saturation]

I think it was just at the transition to Agilent from HP, so the meters had both HP and Agilent branding, but the same model numbers: the 970 series, 1,2,3,4 and then another single model, 2373a.  They stopped selling ~ 2001.   Finding photos online was not as prolific as other meters.






So I estimate, in ~1989 as HP 2373a, 1990s with 970 series until they became Agilent, out 2001, back in 2007.

You're right alm, I forgot to add handheld, so correction made.  It does look like Agilent'a handheld models are heavily Escort influenced, [for others unaware, a Taiwanese company purchased by Agilent in the early 2008, http://www.agilent.com/about/newsroom/presrel/2008/10jun-gp08008.html].
http://www.evaluationengineering.com/index.php/solutions/instrumentation/dmm-is-an-understatement.html

So when was Agilent in the handheld business before the Escort acquisition? In-out suggest that they were in the business at some point, stopped selling handheld, and re-entered the business some time later. I'm not aware of any serious attempt to get into the handheld market before, but it's quite possible that I'm simply not aware of their previous handheld DMMs.

Interesting opinion on DMM's future:
http://www.evaluationengineering.com/index.php/solutions/instrumentation/dmm-is-an-understatement.html

Not that surprising, every manufacturer says their products are the future. NI says that the monolithic instrument is dead (and have been saying this for how long?). There's even a company preferring VXI/PXI over LXI (seems kinda backwards). But a neat overview of some DMM features, thanks for the link.

[alm]

I was unaware of those, thanks for the information, I stand corrected. The 970 kind of looks like the Fluke 80 series, only the range switch and mechanical shutters give it away. I've never seen any of them, either in use or for sale. I wonder if they stopped producing them because Fluke filed a lawsuit, I believe they did have a legal struggle with Tektronix in the nineties, which ended in Fluke buying the Tek DMM line. These days Tek sells Fluke DMM's under their own name.

[saturation]

You're welcome, Fluke did get litigious on anyone copying the form and particularly, the rubberized DMM sleeve, causing a lot of folks to change the color to anything but Fluke yellow.

But I think its obscurity is less likely to be about litigation.  I read of DMM history in an EDN or some trade rag article about the new Agilent line, and it looks like the last HP/Agilent DMM line had a 10 year run time.  Despite that, its very uncommon to find photos or general data on them from google. So my guess it didn't sell well.

I was unaware of those, thanks for the information, I stand corrected. The 970 kind of looks like the Fluke 80 series, only the range switch and mechanical shutters give it away. I've never seen any of them, either in use or for sale. I wonder if they stopped producing them because Fluke filed a lawsuit, I believe they did have a legal struggle with Tektronix in the nineties, which ended in Fluke buying the Tek DMM line. These days Tek sells Fluke DMM's under their own name.

[Rhythmtech]

Fluke also understate specs, Fluke 85-I is rated at 0.5%+1 digit across all Vdc ranges, actual is more ~10x better.

Unlike excellent competitors from Agilent or Gossen Metrawatt, some Fluke models such as the 80s series, are still made, almost the same, continuously, for 20+ years.  So there is a good chance you'll get a Fluke with a similar real long term stability, not just a lab tested 'accelerated aging' test.

The accuracy statement includes the temperature operating range. So they most likely calibrate it to be most accurate ~25 C but it must adhere to the .05% within much wider environmental constraints -

Environmental Specifications
Operating Temperature    
    -20°C to +55°C
Storage Temperature    
    -40°C to +60°C
Humidity (Without Condensation)    
    0% - 90% (0°C - 35°C)
    0% - 70% (35°C - 55°C)
Operating Altitude   
    2000 m

Fluke is not just a multimeter company and they already make what many believe to be the best meters on the market there is no reason for them to redesign.  Their calibration products are from what I understand the most common on the market.  They also sell quite a few power quality analyzers which is in important as buildings are held to stricter power efficiency requirements all of the time.

The fact that companies like Agilent and Gossen Metrawatt / Danaher do not have the same business model is somewhat of a tribute to Fluke making things right the first time around, but more than likely it's done to try to steal market share away from the yellow boxes that everyone gravitates to first. 

[saturation]

Many thanks for emphasizing that R, that it would hold to those specs under those conditions is good.  I should have mentioned that too, but it escaped me.  There are other cheaper meters with accuracy rated as good as the 87V, but I really wonder how they would hold up to extremes of environmental operation?

I just posted a quick review of an 87V I got on eBay on another thread.  I'm now doing function testing, and I did a test of the Vdc range from 10mV to 30V against my HP 3456A.  It solidly at 0.03-.005% at room temperature, much closer to the published specs than the 85 is.  Anyway, just for kicks, after realizing I didn't test it under more extreme environmental conditions, put 3 meters in the refrigerator and chilled them down to about 32F.  They're still in spec, with the 85 still reading 10x better than the published spec.  However, the Radio Shack DMM went berserk, and it is rated to operate at 32F.

Fluke has some advertising about our soldiers in Iraq and how the LCDs malfunctioned at 135F, but recovered once it cools down.  But I'd like to test just how accurate it is toward 100F, so I'll wait for another hot sunny day, rather than use my toaster oven 

Fluke also understate specs, Fluke 85-I is rated at 0.5%+1 digit across all Vdc ranges, actual is more ~10x better.

Unlike excellent competitors from Agilent or Gossen Metrawatt, some Fluke models such as the 80s series, are still made, almost the same, continuously, for 20+ years.  So there is a good chance you'll get a Fluke with a similar real long term stability, not just a lab tested 'accelerated aging' test.

The accuracy statement includes the temperature operating range. So they most likely calibrate it to be most accurate ~25 C but it must adhere to the .05% within much wider environmental constraints -

Environmental Specifications
Operating Temperature    
    -20°C to +55°C
Storage Temperature    
    -40°C to +60°C
Humidity (Without Condensation)    
    0% - 90% (0°C - 35°C)
    0% - 70% (35°C - 55°C)
Operating Altitude   
    2000 m

Fluke is not just a multimeter company and they already make what many believe to be the best meters on the market there is no reason for them to redesign.  Their calibration products are from what I understand the most common on the market.  They also sell quite a few power quality analyzers which is in important as buildings are held to stricter power efficiency requirements all of the time.

The fact that companies like Agilent and Gossen Metrawatt / Danaher do not have the same business model is somewhat of a tribute to Fluke making things right the first time around, but more than likely it's done to try to steal market share away from the yellow boxes that everyone gravitates to first. 

[johnboxall]

If I may add my own very unscientific comparison of a Tektronix CFC250 frequency counter - over 20 years old. $20 from eBay. Fed it a sine wave as well as the Fluke 233, the Tek almost spot on after all those years: http://www.flickr.com/photos/tronixstuff/sets/72157624700675762/
Fluke, Tektronix, Hameg etc... might cost more up front, but will last.

[alm]

I would expect the counter to have a better accuracy spec than the DMM, especially at higher frequencies, so it's hard to verify that with a DMM. But it at least seems to be in the right ballpark.

[saturation]

Yes, that's great.  Oldies are goodies.   That model Tek is rated to 100 MHz isnt' it and the Fluke 233 to 50kHz?  Its already reading to 94kHz here.




As alm suggests, counters show their stuff at the limits of its range.  I see a function generator above one your pics, why not push it way up its rated frequency and see when it gives up ?  Also, test with square and triangle and see how both compare.

I did the same for Fluke 85-I rated at 200kHz, but I found counts accurately to 800kHz.

https://www.eevblog.com/forum/index.php?topic=511.0;wap2

If I may add my own very unscientific comparison of a Tektronix CFC250 frequency counter - over 20 years old. $20 from eBay. Fed it a sine wave as well as the Fluke 233, the Tek almost spot on after all those years: http://www.flickr.com/photos/tronixstuff/sets/72157624700675762/
Fluke, Tektronix, Hameg etc... might cost more up front, but will last.

[alm]

I wasn't really referring to the bandwidth, but to the accuracy. The CFC250 is rated for about +/- 14 ppm with 1 year calibration cycle (+/- 10 ppm aging per year, plus +/- 10 ppm for line voltage variation), probably more if it was last calibrated a long time ago, but less than 10 ppm per year, since aging tends to decrease with age. The Fluke 233 is rated for 0.1% frequency, or 1000ppm. It's impossible to verify the 14ppm or so spec with a 1000ppm reference. Some DMM's are better (the 87 is probably better), but in general, DMM's tend to be lousy frequency counters. Low accuracy, low precision, low bandwidth and high input capacitance. So even the low-end CFC250 is a much better counter than any DMM.

[slburris]

I did the same for Fluke 85-I rated at 200kHz, but I found counts accurately to 800kHz.

My Fluke 87-V is rated to 200khz but works up to 660Khz.  Above that it just
displays 0, so at least it doesn't just throw bogus numbers at you.

Is it just me, or do you find the LED displays of the older equipment more readable?
The Fluke LCDs are quite good when backlit, but I still prefer LEDs. 

Of course I also prefer Nixie tubes, so maybe it's the warm glow of the digits,
rather than the coldness of the LCDs, but that would be an artistic judgement,
not a technical one :-)

Scott

[saturation]

Yep, that's vital.  As alm mentions, what good is reading frequency if its inaccurate too?  I just got a second hand 87-V that I haven't had time to test beyond Vdc, so I'll post later its results.  I also just got an 85-III, which is also true RMS, for $86. I just so happened to pass by eBay at the right time and couldn't resist the price.

I anticipate the upper limits of its frequency response to be variable over time and environmental conditions, but within the specified limits, to be stable and accurate.  But, it'll make for interesting tests, I'll put the meters in the freezer and see what happens.

Yes, I do find Fluke's older reflective LCD easier to look at [ comparing the 85-I to the 87-V] when you put them side by side.  But, older LCD in general are not as clear or contrasty so I avoid those types, given a choice.

Yes, I do like LED better, easier and faster to see.   I think some modern instruments are being made with those displays, my Instek DDS FG uses it too.   Not much flexibility in presenting anything but numbers, but just right if that's all you need.

I did the same for Fluke 85-I rated at 200kHz, but I found counts accurately to 800kHz.

My Fluke 87-V is rated to 200khz but works up to 660Khz.  Above that it just
displays 0, so at least it doesn't just throw bogus numbers at you.

Is it just me, or do you find the LED displays of the older equipment more readable?
The Fluke LCDs are quite good when backlit, but I still prefer LEDs.  

Of course I also prefer Nixie tubes, so maybe it's the warm glow of the digits,
rather than the coldness of the LCDs, but that would be an artistic judgement,
not a technical one :-)

Scott

[saturation]

Yes, agree fully alm, I presume tronixstuff was just marveling at how old gear made by famous makers still work decently decades later.  I think your point is you can't check a micrometer's accuracy with a ruler, while tronixstuff is happy his $30 buy still works decently.  When you buy stuff off eBay or second hand, its hard to know it really works anywhere to factory specs unless you retest its capabilities, or do some form of primitive calibration referencing whatever you have at hand that measures well.

Thanks for the details of the Teks accuracy and reliability.  

I recently found a B&K counter that looks like it was made by Lutron, that reads to 1.5 GHz, and the current Lutron model to 2.5GHz at ~ 4ppm/year [claimed! ].





Its been out of the B&K catalog for almost 10 years, but one seller still has them new for $90, which is a steal for a counter of this type.

I've checked its readings against the Instek DDS FG 1023 [ which has a calibration certificate from Taiwan dated 4/10] rated at Stability ±20ppm, Accuracy ±20ppm, Aging ±5ppm/year.

The counter does concur with the FG settings to its limits, only 3MHz.  So at least its as good as the DDS FG to 3 MHz, but I don't have anything near 4 ppm or 1 GHz.

I wasn't really referring to the bandwidth, but to the accuracy. The CFC250 is rated for about +/- 14 ppm with 1 year calibration cycle (+/- 10 ppm aging per year, plus +/- 10 ppm for line voltage variation), probably more if it was last calibrated a long time ago, but less than 10 ppm per year, since aging tends to decrease with age. The Fluke 233 is rated for 0.1% frequency, or 1000ppm. It's impossible to verify the 14ppm or so spec with a 1000ppm reference. Some DMM's are better (the 87 is probably better), but in general, DMM's tend to be lousy frequency counters. Low accuracy, low precision, low bandwidth and high input capacitance. So even the low-end CFC250 is a much better counter than any DMM.

[alm]

I agree that tronixstuff's test was a reasonable test that the counter was working and not totally out of wack. I believe the range that includes the CFC250 was introduced in the early nineties, that's actually pretty modern equipment in my book .

Frequency measurement down to the sub-ppm level isn't that hard, just ask any member of the time-nuts list (no, not me). Even a reasonable TCXO can do 1ppm long-term, an OCXO I have (got it for the price of shipping) is specified as < 1.5*10^-7 per year, and Rubidium or Cesium references are even better. A GPS disciplined reference like the Thunderbolt can do something like 10^-10 long term. Once you have a stable reference, counting with an uncertainty of 1 count is fairly easy. Many counters can use an external 10MHz reference oscillator.

Measuring frequency accurately is much easier than voltage, even a 1ppm/year voltage reference is pretty expensive, and you'd probably need a national standards lab for 10^-10 tolerances. Nothing like nice GPS signals that give you an accurate voltage reference that won't drift for $100.

[johnboxall]

Thanks to alm and saturation for your information. And I love that evolution of the HP 3456A meter. I'm still learning! When I get working after graduation my shopping list includes some
nice-smelling new test equipment.
Yes, I was just staring at the old Tek and my Fluke 233 and wondered how they compared. I have repeated the test, this time seeing how far the Fluke can go.

With sine wave, 99.48 kHz. I couldn't adjust the frequency any higher without going into "ol" overload on the Fluke



Square wave. 99.96 kHz.



I don't feel that confident comparing the function generator against the Tek as the dial on the generator isn't that well marked.



cheers
john

[saturation]

Welcome.  Interesting, it just cuts off ~ 100kHz.

The 3456a is very cost effective and accurate home lab or hobbyist "super" DVM. It has been selling on the low end, for each meter, with shipping, for $100,$500, $3000 respectively for 345 -6/7/8 working units.  For the price of a made in China handheld, you can get a lab grade DVM in the 3456a that realistically fixable by most folks on a budget, but the drawback is its slower, physically large and has no amps range.

 - alm, if you're reading here, is there anything better than the 3458a spec wise?

Thanks to alm and saturation for your information. And I love that evolution of the HP 3456A meter. I'm still learning! When I get working after graduation my shopping list includes some
nice-smelling new test equipment.
Yes, I was just staring at the old Tek and my Fluke 233 and wondered how they compared. I have repeated the test, this time seeing how far the Fluke can go.

With sine wave, 99.48 kHz. I couldn't adjust the frequency any higher without going into "ol" overload on the Fluke

cheers
john

[alm]

The Fluke HP 3458A had better specs than the HP one (though I believe the difference was just one resistor). The Fluke 8508A is currently the most accurate general purpose lab multimeter, as far as I know.

It's kind of funny. For 'normal' folks like us, the HP 3458A is like the holy grail of lab multimeters. I was reading the PMEL (army/air force/navy calibration lab) forum, and they complained that the 3458A was useless for anything but DC, and preferred the 8508A.

The HP 3458A is fairly old (1989 or so), from memory, I think the 3457A came out in 1986/1987, and the 3456A in '81, not sure about the 3455A (late seventies?). I would have expected a 3459A somewhere in the past 20+ years.

Does the 3457A really fetch $200 more than the 3456A in similar condition? They both have some pros and cons, no clear cut winner as far as I'm concerned. I had a choice between a 3456A (tested, good history) and 3457A (lightly tested, gave calibration error about current range) for $50 extra. I chose the 3456A because of the better display and better stability, and because the current range on the 3457A was probably bum anyway. So in my opinion, the prices should be pretty close. The 3456A was more expensive than the 3457A when both were current products, and the 3455A was even more expensive.

[hpxref]

Thanks for the various confirmations of Fluke's good name in DMM's
I used Flukes at work for many years  until the LCD displays went dark or leaky

Wanted one for myself but a new one financially out of reach and ePays prices were astronomical for 2nd hand ones.  Eventually got an ex Forces TEK DMM916
Checked it against my in CAL Agilent 34401A  and it agreed right across all ranges.
Ime lucky to own reasonable DC/AC Cal sources (Fluke and eSi) including an eSi Dekatran DK72A
and the 916 sits smack in the centre of its published specs on all ranges!
Not bad for a 2nd hand DMM.  Tek must have learned well from Fluke (and its blue rubber holster is
easier to keep clean than Fluke yellow!)
This DMM  is also not well known either. If you cant afford a Fluke its a good alternative

John