How many Fluke meters can you daisy chain to a 5520A?

[CalibratorJ]

Man can't have any fun around here anymore......

And no, you can't daisy chain attenuators..... on a PNA or elsewhere. If you had ever used a PNA you would have gotten the joke, -80 db puts the trace at the bottom of the screen.... looks perfect...... but if you have to explain it, well guess that kinda kills the joke......

Ok, back to daisy chaining dmms and spec ans.....

[Hawaii596]

I love the impedance check where you use an assortment of T connectors and an HP 909A 50 Ohm termination.  You can do up to three network analyzers simultaneously (for those who don't understand - kidding).

[RFCAL]

you know, every lab I worked in did not allow this practice. I must have worked in legit labs--US NAVY, DOD,HP,Agilent,etc.

[Hawaii596]

I never do that any more, really.   In an ISO17025 world, besides the practical implications of loading the output of the calibrator, you would need to account for the uncertainty introduced, and of course what procedure you use that allows multiple meters (none).  Matter of fact, I believe it was the Datron 4808 that I used a number of years ago, that when you connect it to lower input impedance meters (such as a Simpson 260), it would not adequately regulate and you would get erroneous out of tolerance readings.  So even simple handheld DMM's might get erroneous results.

[Duckbutta]

Accreditation and the infiltration of metrology by the mathematicians has ruined this once great career field. Listen to yourselves. WE ARE TALKING ABOUT HANDHELD DMMS FOR CHRIST'S SAKE! WAKE THE HELL UP! Microvolts of uncertainty on the 200 mVAC range of a Fluke 87 is not even worthy of consideration. You guys are really overthinking this. And what good is data on a handheld DMM? No one has been able to offer me a legitimate explanation yet.

[ck454ss]

Accreditation and the infiltration of metrology by the mathematicians has ruined this once great career field. Listen to yourselves. WE ARE TALKING ABOUT HANDHELD DMMS FOR CHRIST'S SAKE! WAKE THE HELL UP! Microvolts of uncertainty on the 200 mVAC range of a Fluke 87 is not even worthy of consideration. You guys are really overthinking this. And what good is data on a handheld DMM? No one has been able to offer me a legitimate explanation yet.

Since when do we judge how important a piece of equipment is?  I have no idea what the use is of a piece of equipment is.  Ill give my customer the best cal I can provide at a reasonable cost.

It may be "Just a Fluke 87" but I was a part of a a Fluke 77 fiasco back in the early 90's at Pearl HArbor in which a submarine was sent back to port because a technician was concerned that the reactor may not have been started properly because of a simple Fluke 77.  It cost the Navy millions and it was not fun calibrating a meter in front of the Admiral.  But it was "Just a HandHeld Meter" right...

[USMCPMEL]

I think your missing the point. It is not that we "judge" how important the meter is. It is that there is almost no change to the accuracy of the 5520A when doing this. When they said it is not important they meant it does not change the accuracy enough that you would EVER see it on the handheld DMM. That being said I would not recommend daisy chaining a 34401A or higher accuracy instruments together because it is much closer to a 4 to 1 ratio and it might actually change some readings there. Although I would love to see some actual data instead of just opinions. Anyone done any actual tests to see if this changes anything??

[Duckbutta]

ck - If there was a problem with the Fluke 77 I assure you that it wasn't because it was daisy chained during cal. I stand by my comment, no matter what the end use of the item is, the standards only have to be "good enough" (4:1). You take yourself to seriously. Get over yourself.

[jimmyc]

there is almost no change to the accuracy of the 5520A when doing this.

"there is almost no change" is not a measurement.  though there are too many mathematicians, our job is still to know what and how we are measuring everything.  will 3 take the calibrator out of tolerance? 4?  10?  as long as it resettles is the accuracy the same?  there are a lot of variables there.  could i gang together 300 pressure gauges? 

[USMCPMEL]

The Fluke 77-4 is accurate to +-2% +-2 counts. The fluke 5520A is accurate to .012%. Unless someone is going to go out and do some type of study to show me that it will make a difference I will never believe that the accuracy would degrade enough. As I had stated I would only do that when we were calibrating no data. I have a very hard time believing that it would make a difference even if you were calibrating with data.

[Top Gun Test]

Unless the uncertainty's have been done for a " Daisy Chain "
Then as Metrologist you follow the proper way of doing things.
Not the unknown variable UNTIL YOU HAVE PROVEN  IT .
We are  test and measurement  people . Standards and practices
need to be followed. If we all decided it " Good Enough " then what
is Bad and what is good What is your standard of thinking .
Until there is proof with the calculations then I say do it the tried and true
method .   But if you want to play with Fire and the Auditors and the consequences
behind this practice so be it. We adhere to procedures and specs and calculations.
Please don't teach these practices to the new people , they need proper guidance .   

[griff61]

I've found that in the time wasted in the set up for daisy chaining handhelds, I could probably have calibrated 2 or 3 already, they're not exactly rocket science. I never really saw much of an advantage in daisy chaining. The things you might daisy chain are usually so simple, it's usually faster to just do the damn thing.

[Top Gun Test]

Guys Im done with this email chain , and I understand the
reasoning that people have with the Daisy Chain on DVM
ect . Its a harsh commercial environment and Time equals
money . I understand the pressure of the Cal Techs to produce and
meet quotas and have a 3-1 ration of billings to pay , at a minimum .
Recommendation to eliminate   all this and stick to High End Cal and then
spend the time to do it right (I wish) . At least in a perfect world , LOL
But I understand the pressure is to produce and bill . So be it .
What would you guys say is the Quota of Billing to salary ??
3-1 on average

[sdmetrol]

If the company you work for actually has a quota, I would say you are working for a poorly managed lab.  Your salary should reflect the expertise you bring to the lab along with the production you can generate.  Having said that, I would say that if you are primarily a technician in the commercial field, and you can not generate enough production to cover 3 times your yearly salary, your lab does not charge enough or you do not work efficiently enough (organize, automate, upgrade standards & technique, etc.).

[Top Gun Test]

Just wanted the general feeling of the ratio SD Metrol .
What would you say the average ratio is ?  Im sorry if I offended you
with that question. And Im a repair guy . I like to keep separate from
cal to give the repair a unbiased judgment in cal. AKA no fudge factor .
But  Im a Lowry 1983 grad . So I do know cal pretty good , but not physical
dimensional as I believe you are . Strickly a RF guy and various calibrators
in the calibration realm. So please don't feel offended when I say ratios .
I know a lot of Cal Labs work as such and I do agree that it shouldn't matter.
But also 3 rd Party Calibration is a business and has to be profitable in order to survive.
Just was curios what the rate was out there for seasoned cal techs . And its
best to state a ratio without people giving actual salary or hourly numbers .
So I hope your following me about my  question  and why it was stated as such .