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so ive been looking at ebay for a used fluke 87 and found some III's and V's
i had posted a previous question about buying safely on ebay for a fluke and i got the hang of it but now i wanted to ask about what to do when i actually go the thing.
i do have access to a physics lab with power supplies and such so i can test the meter out that way but if its messed up how much would it cost to calibrate the meter (if its either the III or V) and get back to working order? would it be wise to go ahead and get it calibrated or whatever anyways when i get it?
there are some meters that do not come with leads and cases. how much would it usually cost to get them?
do flukes hold up for a good period of time when being used? as in their readings are good and such if it looks and sounds like it wasnt terrible abused or used?
What is the differnce between the fluke 87 III and the fluke 87 V? i wanted to make sure bc all i can remember is that hte V is just newer and thats it.
if you have any other advice/suggestions i would appreciate. thanks -
I think Fluke wants something like $120 or so for calibration, I'd guess something like $75-$125. That's probably a significant part of the price, so I would see if it's not really off and try to compare it with other meters (preferably calibrated), as long as it's reasonably close, I'd assume it's fine. Fluke meters usually don't drift much unless something's damaged. Leads can be had for a few dollars (but quality ones like the original Fluke ones are more expensive). I wouldn't use the really cheap ones for dangerous voltages like mains, but they're probably fine for extra low voltage stuff. Re case, if you mean the rubber holster, check Ebay. If you mean a leather/fabric case, anything that fits (like a case to carry an external hard drive) will be fine, so you can probably find something cheap locally.
Search the forum for the differences between the various versions, there has been a fair amount written about it. From memory, the version V has a nicer display/backlight, probably fixed the zebra contacts issue, and add some features that in my opinion are of minor importance for non-industrial work, like a low pass filter for variable frequency motor drivers. -
Does anybody know what is involved with Fluke's calibration?
The reason I ask is other BIG test equipment manufacturers may offer a "calibration" service, but this is in reality simply confirming that your unit is within the published specification for that device.
If found to be outside the published specs, the unit is deemed to have failed calibration, but if you offer more money they can then perform an adjustment...
ie the calibration does not involving performing adjustments to the device.
Worth bearing in mind, especially if you think your unit freshly returned from calibration is now spot on. -
According the European procedures, Fluke will adjust the equipment (if possible) if it's at least 70% out of tolerance, at least for the cheapest level (which is all you need as hobbyist), there is a higher level which doesn't provide adjustment, probably for companies doing their own characterization. From the US offerings, it looks like everything except a performance test provides adjustment.
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To add to prior posts, Fluke provides the calibration and adjustment manuals for the 80s series, you can download it off their site. Its very detailed and describes what voltage, signal etc., sources you need and its rated accuracy.
One of the benefits of the III ?? [ maybe 4] and up versions, is adjustment are all electronic and can be done through the front controls, the older generation 1-2 [ maybe up to 3??] have pots than need tweaking with a screwdriver.
The adjustments are very straightforward, you very likely cannot destroy the meter like you would hacking the Rigol 1052E.
Essentially you set the voltage source to e.g. 12.34V dc, and if you meter doesn't read 12.34, adjust XYZ until it does. Repeat for various ranges.
Fluke leads are ~ $20-30 new, but they are rebadged Pomona, and for CAT III and below use, you can find them for < $20.
Cases can be bought eBay for ~< $20 or bought new from the Fluke store.
My 85 remains accurate in V DC, AC and ohms uncalibrated since 1989. I know this because I recent got hold of a NIST calibrated DMM, and a frequency source and compared it. I certainly didn't expect it to be this accurate 20 years later.
III vs V
so ive been looking at ebay for a used fluke 87 and found some III's and V's
i had posted a previous question about buying safely on ebay for a fluke and i got the hang of it but now i wanted to ask about what to do when i actually go the thing.
i do have access to a physics lab with power supplies and such so i can test the meter out that way but if its messed up how much would it cost to calibrate the meter (if its either the III or V) and get back to working order? would it be wise to go ahead and get it calibrated or whatever anyways when i get it?
there are some meters that do not come with leads and cases. how much would it usually cost to get them?
do flukes hold up for a good period of time when being used? as in their readings are good and such if it looks and sounds like it wasnt terrible abused or used?
What is the differnce between the fluke 87 III and the fluke 87 V? i wanted to make sure bc all i can remember is that hte V is just newer and thats it.
if you have any other advice/suggestions i would appreciate. thanks -
BTW, a quick test to help ensure your Fluke is still accurate and working is to probe the uA/mA socket while on ohms. It should read pretty close to spot on 1K
Useful if doing a quick inspection before buying 2nd hand or whatever, or asking an ebay seller to do who "doesn't know how to test these things"
Dave. -
Is this going to ensure the accuracy and functionality of all the functions or simply the resistance measurement?
BTW, a quick test to help ensure your Fluke is still accurate and working is to probe the uA/mA socket while on ohms. It should read pretty close to spot on 1K
Useful if doing a quick inspection before buying 2nd hand or whatever, or asking an ebay seller to do who "doesn't know how to test these things"
Dave. -
Is this going to ensure the accuracy and functionality of all the functions or simply the resistance measurement?
No, but it tells you that the reference voltage is spot on, and probably part of the precision resistor network as well. As it's unlikely that the current shunt resistor would drift in the opposite direction to the voltage reference reference and give you a "false positive" reading for example.
I'd be very surprised if you could have resistance measure spot on and voltage be out of spec for example (in a fluke, other meters may vary).
Dave. -
I like to believe that the auto-range DMM are easy to check for accuracy.
If its off in one range , its off to all .
But even if I got from ebay as " Calibrated " my Fluke 8050A , I liked to had my own little gadgets,
that would verify basic accuracy and stability .
One tricky point about the Fluke 87 are the Fuses ,
by studying a bit this matter , found that every Fuse type has its own internal resistor.
If the meter comes with the genuine Fuses , it stays accurate even just from that.
As the resistor of the specific fuse - fuses , was known at the master ( factory ) calibration - adjustment .
( I had become as expert in all those , but I had no choice , now I own 8 meters ..
)
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BTW, a quick test to help ensure your Fluke is still accurate and working is to probe the uA/mA socket while on ohms. It should read pretty close to spot on 1K
Useful if doing a quick inspection before buying 2nd hand or whatever, or asking an ebay seller to do who "doesn't know how to test these things"
Dave.
One more thing I should have been able to derive myself. Oh well.
Dave, would you allow me to add this check to my Ebay Fluke guides?
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At my 87-5 ( V )
I get 1001 at uA
And 0.2 at Amperes
One Tip for all, touch the lead at the inner upper area at the leads hole ..
Just at the very begging of the hole ..
Or else you will get LEAD alarm and 1.5 MOhm readings .. -
One Tip for all, touch the lead at the inner upper area at the leads hole ..
Just at the very begging of the hole ..
Or else you will get LEAD alarm and 1.5 MOhm readings ..
That's a good point. If one is asking an e-bay seller, who may be inexperienced, to do this check, it's probably better to plug the negative lead in the current jack and touch the leads together. (then they will get confused, plugging the black lead in the red jack, and you can explain that the current doesn't care.)
When I get home from work, I'll have to see the resistance of the current shunts in other models. -
plugging the black lead in the red jack, and you can explain that the current doesn't care.)
Sorry but you sound as a bit inexperienced your self ..
If you plug any lead at the " uA Amp " ranges at the Ohm scale , you get LEAD alarm on the spot.
Touching the Positive lead ( Ohm ) at the " uA Amp " ranges as I described above,
are the only way to do this test. -
I've got two or three blown fuses that say I ignore lead warnings.
For the 87-III and earlier - you can still read the resistance on the screen, you just have to ignore the beeping. (I have only a 87-III at work, so that's all I can check at the moment. Despite the beeping, I can still read 1.003 K.) So my experience isn't as lacking as you might think.
Only the newer meters display "lead" and prevent you from reading this resistance. (I rarely use my 87-5) Some of the lower end meters will simply flash "lead" when you change from current to something else, or vice-versa, but only for a second or two, you can still read the resistance.
"Back in my day, we didn't have "lead warnings," and we LIKED it."
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"Back in my day, we didn't have "lead warnings," and we LIKED it."
Back in my day, we was riding dinosaurs , but we do not do that any more ,
it damages the highway ..
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Back in my day, we was riding dinosaurs , bad we do not do that any more ,
Plus the fuel probably got too expensive
it damages the highway .. 
.No, but it tells you that the reference voltage is spot on, and probably part of the precision resistor network as well. As it's unlikely that the current shunt resistor would drift in the opposite direction to the voltage reference reference and give you a "false positive" reading for example.
Nice way to test basic voltage measurement, the current source for resistance measurements, and the internal low-current shunt. The main things it misses are parts of the divider network, both for resistance and for voltage, and the 10A shunt. I do occasionally see meters with defects like dead high resistance ranges or a dead voltage range, but you have to cycle through the all ranges with something like a battery and a resistor to test those. Another possible issue is the calibration constants (eg. some idiot messed with the calibration), these are fixable, but might almost double the price if you got the meter for something like $100. These are often separate for each range and function, so you have to test all ranges for those.
I'd be very surprised if you could have resistance measure spot on and voltage be out of spec for example (in a fluke, other meters may vary).
I try to do a full performance verification according to the service manual after I receive something (so I can complain) or if I pick it up. It might annoy the seller, but if you sell something as-is, I'm going to do my best to figure out any faults before giving you my money. It depends on the price, I'm willing to take more risks if it's cheap enough. -
Dave, would you allow me to add this check to my Ebay Fluke guides?
No problemo.
Dave. -
If you plug any lead at the " uA Amp " ranges at the Ohm scale , you get LEAD alarm on the spot.
Touching the Positive lead ( Ohm ) at the " uA Amp " ranges as I described above,
are the only way to do this test.
No, you can do it as Excavatoree said. Yes, the meter beeps at you and shows "LEAD", but it also alternates the display between the actual reading.
Mine shows 0.9985K, not quite spot-on.
Dave. -
Ok my last attempt to express my self .. correctlyQuote
If you plug any lead at the " uA Amp " bananas and the meter are at the Ohm mode , you get LEAD alarm on the spot.
Do we agree here ... ?
Touching the Positive lead ( Ohm ) at the " uA or Amperes " bananas as I described above,
are the only way to do this test.QuoteMine shows 0.9985K, not quite spot-on.
Its best to check your battery first , and then to do the test. -
Ok my last attempt to express my self .. correctly
QuoteIf you plug any lead at the " uA Amp " bananas and the meter are at the Ohm mode , you get LEAD alarm on the spot.
Do we agree here ... ?
Touching the Positive lead ( Ohm ) at the " uA or Amperes " bananas as I described above,
are the only way to do this test.
No, I do not agree, you are incorrect.
It is possible to plug the lead into the uA/mA jack and measure resistance at the same time as I have stated. It is just annoying because it alternates the display and beeps at you.
Dave.
Dave. -
Tried it, I get 1003, or +0.3% off assuming 1000 is right.
Dave's value is actually better, 998.5 is -0.15% off 1000.If you plug any lead at the " uA Amp " ranges at the Ohm scale , you get LEAD alarm on the spot.
Touching the Positive lead ( Ohm ) at the " uA Amp " ranges as I described above,
are the only way to do this test.
No, you can do it as Excavatoree said. Yes, the meter beeps at you and shows "LEAD", but it also alternates the display between the actual reading.
Mine shows 0.9985K, not quite spot-on.
Dave. -
I get 1.003 which seems correct as there are about 0.2 - 0.3 ohms resistance in the leads (Fluke 87 V)
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mine 278 - 9,997 ohm ? ( on 0.025% meter I get 3 count out , and on the 0.05% I get 5 count out ? wierd ! )
the 87V - on 6000 count- 1,000 ohm (spppot on
)
on 20,000 count - 10,005 ohm (and it is used and I dont know what is the age , but I think it is a few years old )
have a nice day !
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Note that while this is a decent test of basic functionality, you should not consider this a way to test its accuracy down to the last digit. There is no reason for Fluke to tightly control the shunt value. Any stable value will do: they can easily compensate for any value by changing the cal constants.
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thanks ,
yep I know, but it;s still fun to look at this number
especcialy when compare to my 287 , I am getting only 2 count diffrnce , while comparing the reading (paralel ) I get the same current esacly ( the 87 read like a 0.1767 while the 287 read 0.1767 abit faster )
BTW , if the resistance of the percsision resistor changes via the tem'p , canno't we compenset that via thermistor/thermo couple ? (IE , define that every 0.1C = 0.02ppm to add or something like this ..)
or there is somthing like this ? if so . whats the name of it ?
thank you in advance !