Fluke 189: it is possible to calibrate it "at home"?

[Starflex]

Hello!
As you can read in my previous post, I'm watching for some meter...
I had found some Fluke's used meter..but I have some doubts about its
calibration: if I buy a meter that had lost its calibration, is posible to
"recalibrate" it at home, or I must ship it to a proper center?
Thank you!

 

[Starflex]

Hello!

[SNIP]

Uhm.. I've read the manual...and I think that isn't possible... :-(

 

[N Cook]

Hello!
As you can read in my previous post, I'm watching for some meter...
I had found some Fluke's used meter..but I have some doubts about its
calibration: if I buy a meter that had lost its calibration, is posible to
"recalibrate" it at home, or I must ship it to a proper center?
Thank you!

See threads , titled Digital Voltmeter Calibration
and also Calibrate source how?
both last year

 

[Starflex]

N Cook wrote:
[SNIP]

Ok, thank you a lot.
I'm sorry for this question : I don't know that you have already spoken
about this argument, I' m Italian (as you can see reading my post in poor
englih!) and I don't read often this newsgroup...!

Thank you a lot!!

 

[Meat Plow]

N Cook wrote:
[SNIP]

Ok, thank you a lot.
I'm sorry for this question : I don't know that you have already spoken
about this argument, I' m Italian (as you can see reading my post in poor
englih!) and I don't read often this newsgroup...!

Thank you a lot!!

Che cosa li incita a pensarli per avere bisogno di di calibrare il vostro
tester? E quanto esatto deve essere?

 

[Starflex]

Che cosa li incita a pensarli per avere bisogno di di calibrare il
vostro tester? E quanto esatto deve essere?

Ehi! Un altro italiano?? Italiano o sei stato in Italia?
Ok, I prefer to write in English, so also the other readers can understand
(..I think..but with my language probably is not simple!!)
My problem is that I need a general purpose, unique, affordable meter.
I had read that Fluke produces very good meter, but I have also read that
our calibration center - in Italy- ask over 100 Euros for a calibration of a
meter.
You can understand that it is a problem for me (I'm a student..)..especially
when I read that "Accuracy is specified for a period of one year after
calibration".
Probably, it is a cautelative operation....but is very expensive, too...
Moreover, if I buy a meter that is declared for "0,025% precision" in DC
measurement (example)...well...I'm spending a lot of money for a "almost
perfect" meter..and I don't want use it out of calibration...
To use a tester out of calibration after a year, I buy a cheaper "Meterman"
for about 100 $ (that I have read is also a good meter..)..and when it start
to be out of calibration, I change it...
So, this is my problem.
I don't want to buy a meter that, after two years of random usage, need a
calibration that cost about 40% of its total cost...

 

[Meat Plow]

Ehi! Un altro italiano?? Italiano o sei stato in Italia?
Ok, I prefer to write in English, so also the other readers can understand
(..I think..but with my language probably is not simple!!)
My problem is that I need a general purpose, unique, affordable meter.
I had read that Fluke produces very good meter, but I have also read that
our calibration center - in Italy- ask over 100 Euros for a calibration of a
meter.
You can understand that it is a problem for me (I'm a student..)..especially
when I read that "Accuracy is specified for a period of one year after
calibration".
Probably, it is a cautelative operation....but is very expensive, too...
Moreover, if I buy a meter that is declared for "0,025% precision" in DC
measurement (example)...well...I'm spending a lot of money for a "almost
perfect" meter..and I don't want use it out of calibration...
To use a tester out of calibration after a year, I buy a cheaper "Meterman"
for about 100 $ (that I have read is also a good meter..)..and when it start
to be out of calibration, I change it...
So, this is my problem.
I don't want to buy a meter that, after two years of random usage, need a
calibration that cost about 40% of its total cost...

I own a 20 year old Fluke 77 that for all practical purposes is as
measurement precise as I need it to be. Buy a used meter and don't worry
about it.

 

[Starflex]

I own a 20 year old Fluke 77 that for all practical purposes is as
measurement precise as I need it to be. Buy a used meter and don't
worry about it.

Ok, I'm watching some auction on Ebay.
But, you don't have answero to my question: why do you speak Italian? Are
you italian, or you had used babylon translator?

 

[Franc Zabkar]

Hello!
As you can read in my previous post, I'm watching for some meter...
I had found some Fluke's used meter..but I have some doubts about its
calibration: if I buy a meter that had lost its calibration, is posible to
"recalibrate" it at home, or I must ship it to a proper center?
Thank you!

You can build your own single-chip precision voltage reference using
Maxim's MAX6350 (5.0V) or MAX6325 (2.5V):
http://pdfserv.maxim-ic.com/en/ds/MAX6325-MAX6350.pdf

"The MAX6325/MAX6341/MAX6350 are low-noise, precision voltage
references with extremely low, 0.5ppm/°C typical temperature
coefficients and excellent, ±0.02% initial accuracy. These devices
feature buried-zener technology for lowest noise performance.
Load-regulation specifications are guaranteed for source and sink
currents up to 15mA. Excellent line and load regulation and low output
impedance at high frequencies make them ideal for high-resolution
data-conversion systems up to 16 bits."

- Franc Zabkar

 

[Starflex]

You can build your own single-chip precision voltage reference using
Maxim's MAX6350 (5.0V) or MAX6325 (2.5V):
http://pdfserv.maxim-ic.com/en/ds/MAX6325-MAX6350.pdf

"The MAX6325/MAX6341/MAX6350 are low-noise, precision voltage
references with extremely low, 0.5ppm/°C typical temperature
coefficients and excellent, ±0.02% initial accuracy. These devices
feature buried-zener technology for lowest noise performance.
Load-regulation specifications are guaranteed for source and sink
currents up to 15mA. Excellent line and load regulation and low output
impedance at high frequencies make them ideal for high-resolution

Ok, I had seen this chip, thank you for the link!

 

[N Cook]

You can build your own single-chip precision voltage reference using
Maxim's MAX6350 (5.0V) or MAX6325 (2.5V):
http://pdfserv.maxim-ic.com/en/ds/MAX6325-MAX6350.pdf

"The MAX6325/MAX6341/MAX6350 are low-noise, precision voltage
references with extremely low, 0.5ppm/°C typical temperature
coefficients and excellent, ±0.02% initial accuracy. These devices
feature buried-zener technology for lowest noise performance.
Load-regulation specifications are guaranteed for source and sink
currents up to 15mA. Excellent line and load regulation and low output
impedance at high frequencies make them ideal for high-resolution
data-conversion systems up to 16 bits."

- Franc Zabkar

I would suggest a precision source like that plus a high precision resistor
to check your meter against, once a year , noting the results in a record,
also cross-checking all 3 with someone else's calibrated meter every now and
then , also recorded.

 

[chuck]

Hello!
As you can read in my previous post, I'm watching for some meter...
I had found some Fluke's used meter..but I have some doubts about its
calibration: if I buy a meter that had lost its calibration, is posible to
"recalibrate" it at home, or I must ship it to a proper center?
Thank you!

You have the two choices already mentioned:

1. Compare your meter readings to those of a meter known to be calibrated.

2. Build an accurate voltage source.

In either case, you need only note the error and record it on a label
stuck to the back of the meter. In those very rare instances in which
the instrument's ultimate accuracy is required, simply correct the
reading using the recorded information.

I understand your concern, but I believe that digital multimeters tend
to hold their calibration extremely well, even with "rough" handling and
the passage of many years. It is quite unusual, but certainly not
impossible, that one will require recalibration. Meters given away as
promotional items by distributors (i.e., very cheap meters) compare very
favorably in accuracy with Wavetek, Fluke, and HP instruments.

There are other reasons to purchase quality instruments, of course.

Good luck.

Chuck

 

[mike]

Hello!
As you can read in my previous post, I'm watching for some meter...
I had found some Fluke's used meter..but I have some doubts about its
calibration: if I buy a meter that had lost its calibration, is posible to
"recalibrate" it at home, or I must ship it to a proper center?
Thank you!

Depends on what you want to do with it.
If you're in an industrial situaiton, you don't have much choice but to
have it professionally calibrated...whether it needs it or not.
In the US, when ISO9000 started, management looked at the cost
of continuous calibration of EVERY peice of equipment in the plant and
dumped everything that wasn't absolutely necessary. Was a great couple
of years for hobbyists.

As for actual calibration...most of the time, if you stay away from the
bleeding edge of specs...a modern 3.x digit multimeter is always in
calibration or it's broke bad. If you have two different types of
meters, check them against one another. IF they're the same, they're
PROBABLY both ok.

Of course, all bets are off if someone has tried to "calibrate it"
without proper tools and experience.

Simplest thing is to checkit against another meter and not worry about
it. You'll want to do this at least once when you buy a used meter.
If you build calibration sources, then you have to worry about their
calibration.

For most of us, accuracy ain't what it's cracked up to be.
I have two 5.5 digit meters in the attic. Found I never needed the
resolution and all the noise in the last digits was more distracting
than helpful. When you want to know if a 9V battery is good, you
don't need much precision or accuracy.
mike

 

[JANA]

You will not be able to calibrate the meter yourself at home. You would need
the proper set-up and proper calibration references for the particular
voltage ranges (AC and DC), and the precision resistance references. These
reference units also follow scheduled calibrations.

When considering the new price of a Fluke meter and its reputation for
precision and performance, the calibration cost is worth it. Fluke meters
are an industry standard.

Ideally, the meter, or any precision electronic test instrument should be
calibrated once a year. But, for general use it can go a long time without
re-calibration if it is used in an environment where it is not knocked
around or abused.

In the lab where I work, we are having our instruments calibrated according
to their manufacture schedules. We must to this in order to maintain our
high standard of calibrating and checking our customer's devices. We have
some devices for measuring UV intensity that have to be calibrated every 6
months because of safety issues.

--

JANA
_____

Che cosa li incita a pensarli per avere bisogno di di calibrare il
vostro tester? E quanto esatto deve essere?

Ehi! Un altro italiano?? Italiano o sei stato in Italia?
Ok, I prefer to write in English, so also the other readers can understand
(..I think..but with my language probably is not simple!!)
My problem is that I need a general purpose, unique, affordable meter.
I had read that Fluke produces very good meter, but I have also read that
our calibration center - in Italy- ask over 100 Euros for a calibration of a
meter.
You can understand that it is a problem for me (I'm a student..)..especially
when I read that "Accuracy is specified for a period of one year after
calibration".
Probably, it is a cautelative operation....but is very expensive, too...
Moreover, if I buy a meter that is declared for "0,025% precision" in DC
measurement (example)...well...I'm spending a lot of money for a "almost
perfect" meter..and I don't want use it out of calibration...
To use a tester out of calibration after a year, I buy a cheaper "Meterman"
for about 100 $ (that I have read is also a good meter..)..and when it start
to be out of calibration, I change it...
So, this is my problem.
I don't want to buy a meter that, after two years of random usage, need a
calibration that cost about 40% of its total cost...

 

[Usual Suspect]

You will not be able to calibrate the meter yourself at home. You would need

the proper set-up and proper calibration references for the particular
voltage ranges (AC and DC), and the precision resistance references. These
reference units also follow scheduled calibrations.

If you're talking about human safety issues, or some military spec stuff,
3rd-party calibration certification is probably required.

But you can do pretty good yourself at home. There are many circuits
available that show how to build (or buy) very accurate voltage references.
Precision resistors can be purchased for quite affordable prices.

If it's just your home lab, a few tenths of a percent of accuracy is probably
OK.