Fluke DMM questions?

[jasonck08]

I'm considering getting a Fluke DMM (have a cheapo DMM right now) and want something more accurate with more features.

The main features I use the most on a DMM is the voltage reading, amperage reading, temperature reading and continuity tester. I would also like to be able to test resistance accurately.

So my question is simple, what Fluke DMM(s) do you have and why did you choose that specific model over another? What do you like about it? And what feature(s) do you wish it had that it doesn't?

 

[HKJ]

Fluke meters is not as much about features as about reliability, you can get much cheaper meters with many more features.
I am using some of the top meters: 189 and 289, but a good meter for most use is the 170 series (175/177/179), where I also sometimes uses the 179.

 

[a1penguin]

We had fluke meters and DC power supplies in grad school. My Fluke motto: If it works, it must be a Fluke!

 

[olephart]

I got a nice Fluke 175 from ebay for $100. 2 reasons; reliability and it has the minimum Voltage accuracy I want for testing/charging Lithium cells. It's pretty good for amps and continuity testing is trivial for any meter. It also has excellent protection circuits and test probes. No temperature probe.

I use a much less expensive DMM that has a temp probe that is +/- 1*C. Close enough for what I need. I "calibrate" my less expensive meter with the Fluke and am comfortable using it for all LED testing and battery measurements. It's pretty nice being able to read 2 parameters at the same time with confidence in the results.

I donno about "accurate" resistance measurements. I think it depends on the amount of resistance you want to measure. I believe most DMMs are lacking in very low Ohm accuracy and other methods must be employed. Ya may want to do more research for the range intended.

 

[Robin24k]

The Extech/Craftsman meters are also pretty good, and much cheaper. I got the Craftsman Professional 82003 meter because it is IP67 waterproof and also drop-proof from 6.5 ft. I got mine from Ebay for half the retail price.

http://www.craftsman.com/shc/s/p_10155_12602_03482003000P

I also have a Fluke 117, and it has a little more precision (6000 count vs. 4000 count in the Craftsman), but it has no temperature sensor support.

 

[jasonck08]

How often do you need to calibrate a Fluke DMM, where do you do this and how much does it cost?

I'm looking at some 175's and 177 on eBay right now...

 

[jhellwig]

179 I use one every day. The 189 or 289 isn't much of an improvement other than the data logging stuff. The 289 have a little more accuracy but not much more. If I remember right the 189 and the 179 were the same accuracy but the 189 just had some data logging stuff.

 

[45/70]

I also have a Fluke 117, and it has a little more precision (6000 count vs. 4000 count in the Craftsman)......

When comparing a 6000 count meter to a 4000 count meter, the 6000 count meter isn't necessarily any more precise. It depends largely on the inherent accuracy of the two meters. For example, if the 6000 count meter's accuracy on DC Volts is 0.1% + 3 digits, and the 4000 count meter's DC Volt accuracy is 0.025% + 1 digit, the 4000 count meter will likely be more accurate. This could even be true at a voltage such as ~5 Volts. The 4000 count meter may read 5.00 Volts as opposed to the 6000 count meter reading 4.992, or 5.008. In this example the 4000 count meter is likely more accurate.

I realize I am presenting a lot of "ifs" here, but I'm just pointing out that the accuracy of a meter depends on more than just the digit count. Just keep in mind that if a meter's accuracy is 0.1% + 3 digits, it's accuracy is 0.1% + 3 digits, regardless of the digit count.

Dave

 

[alpg88]

i have fluke and amprobe, both are accurate enough for my use, thou i use them often, amprobe costs less very good quality, and has more functions.
unless you are pro electrician, and use it on the job all the time, you should be fine with amprobe.

 

[HKJ]

179 I use one every day. The 189 or 289 isn't much of an improvement other than the data logging stuff. The 289 have a little more accuracy but not much more. If I remember right the 189 and the 179 were the same accuracy but the 189 just had some data logging stuff.

As I wrote above, I uses 179, 189 and 289 and there are many differences between 179 and the two other.

When comparing a 6000 count meter to a 4000 count meter, the 6000 count meter isn't necessarily any more precise. It depends largely on the inherent accuracy of the two meters. For example, if the 6000 count meter's accuracy on DC Volts is 0.1% + 3 digits, and the 4000 count meter's DC Volt accuracy is 0.025% + 1 digit, the 4000 count meter will likely be more accurate. This could even be true at a voltage such as ~5 Volts. The 4000 count meter may read 5.00 Volts as opposed to the 6000 count meter reading 4.992, or 5.008. In this example the 4000 count meter is likely more accurate.

I realize I am presenting a lot of "ifs" here, but I'm just pointing out that the accuracy of a meter depends on more than just the digit count. Just keep in mind that if a meter's accuracy is 0.1% + 3 digits, it's accuracy is 0.1% + 3 digits, regardless of the digit count.

Dave

It is correct that more digits is not enough to give higher precision, but you example is incorrect.

A 4000 count meter (0.025% +1) showing 5.00 means the actual voltage is between 4.9887 and 5.0113

A 6000 count meter (0.1% +3) showing 5.000 means the actual voltage is between 4.992 and 5.008

I.e. the 6000 count has better precision. This will only be the case when the reading is between 4000 and 6000, in all other situations the 4000 count will be more precise.

 

[jasonck08]

Can anyone answer my question regarding Fluke calibration?

"How often do you need to calibrate a Fluke DMM, where do you do this and how much does it cost?"

 

[Meterman]

"How often do you need to calibrate a Fluke DMM, where do you do this and how much does it cost?"

You'll find answers to all questions here.

But I'm sure, you won't be willing to spend that money!

Wulf

 

[jasonck08]

You'll find answers to all questions here.

But I'm sure, you won't be willing to spend that money!

Wulf

No mention of the cost on that page, or how often it needs to be done. I guess I'll email them...

I take it most people don't calibrate their flukes?

 

[J-FRAME]

I love my Fluke and have had it for years BUT for every ones general information I have had 2 sets of Fluke brand leads( black and red )fail inside the molded tip part on one of the leads. I replaced both leads as thats how they are sold. This can really make scratch your head when testing and you get no reading etc,so be warned.

 

[45/70]

.
It is correct that more digits is not enough to give higher precision, but you example is incorrect.

A 4000 count meter (0.025% +1) showing 5.00 means the actual voltage is between 4.9887 and 5.0113

A 6000 count meter (0.1% +3) showing 5.000 means the actual voltage is between 4.992 and 5.008

I was just pulling numbers out of a hat, so to speak, when I came up with those examples. My point was, as you confirmed, that there's more to the precision and accuracy (actually two slightly different qualities) of a meter than the digit count. Now thinking about it, I'm not even sure there exists any 3 1/2 or 3 3/4 digit DMM's with 0.025% +1 accuracy!

Also, if I'm not mistaken, your figures for the 4000 count meter above are based on 0.25% +1 and not 0.025% +1. It would actually be 4.99775 and 5.00225.

Dave

 

[HKJ]

Also, if I'm not mistaken, your figures for the 4000 count meter above are based on 0.25% +1 and not 0.025% +1. It would actually be 4.99775 and 5.00225.

My figures are correct (except for rounding), the tolerance is:
0.025% -> 5*0.00025 -> 0.00125
+1 on 5.00 display -> 0.01
Final range lower bound: 5-0.00125-0.01 -> 4.98875
Final range upper bound: 5+0.00125+0.01 -> 5.01125

 

[45/70]

My figures are correct (except for rounding), the tolerance is:
0.025% -> 5*0.00025 -> 0.00125
+1 on 5.00 display -> 0.01
Final range lower bound: 5-0.00125-0.01 -> 4.98875
Final range upper bound: 5+0.00125+0.01 -> 5.01125

Ok. So you're saying a 0.025% +1 digit meter is less acurrate than a 0.1% +3 digits meter? Sorry, but I'm having trouble with that. :thinking:

EDIT: Never mind. I was failing to consider that the "+x" digits are displayed digits.

Thanks, HKJ. :thumbsup:

Dave

 

[HKJ]

EDIT: Never mind. I was failing to consider that the "+x" digits are displayed digits.

And that is exactly the reason why a 6000 count meter is much better than a 2000 or 4000 count meter for LiIon batteries.

 

[alpg88]

No mention of the cost on that page, or how often it needs to be done. I guess I'll email them...

I take it most people don't calibrate their flukes?

correction, price to calibrate that fluke, was almost the same as that brand new amprobe.

 

[45/70]

And that is exactly the reason why a 6000 count meter is much better than a 2000 or 4000 count meter for LiIon batteries.

Gotcha HKJ. My Fluke 27/FM is clearly in that category, as it's a 3200 Count Meter. I think I can live with being off by a hundredth of a volt, or so when measuring Li-Ion cells though. When compared to the DMM in my Metex MS-9140 (19,999 count) they're very close. Although the Metex is supposedly around twice as accurate, I'm inclined to trust the Fluke more, as it was recently calibrated (before I got it) plus, it's a Fluke.

No mention of the cost on that page, or how often it needs to be done. I guess I'll email them...

I take it most people don't calibrate their flukes?

jason, what I do is check my meters against a calibrated one every once in a while. They never seem to change much, but then again maybe that's because all my meters are really old. I remember checking the cost for recalibration, it's pretty staggering. My friend who has a Fluke 8808A, has to have his calibrated once a year for his work. That's the one I check mine against.

Dave