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

[USMCPMEL]

Before it messes with the accuracy of the 5520A? I have not done this in a long time but I remember techs doing this when I was with Transcat many moons ago...

[Hawaii596]

Depends on what function/range/accuracy of the meter.  Low accuracy meters like Fluke 77, you can do about 3 for DC volts and DC current.  I don't like paralleling/seriesing them for AC functionality as the inoput impedance is lower already.  And resistance, 1 at a time.  I haven't really done that since the old Fluke 5102B days calibrating Simpson 260's.

[USMCPMEL]

I think when I did it I put 3 together and took all my readings that way except for Ohms. Obviously you have to move the leads when your doing the amps but I do not remember any of them ever reading different that way.

[RFCAL]

I'm just shaking my head!!!OMG

[Bryan]

Mid 80's in the Army we fielded the Simpson 467 I think it was, a digital dmm.  Anyway at Ft Hood a guy on our team designed and laid out the diagram, I did the assembly of the "Ganger Banger"  It allowed us to connect up 10 of them and each one had a switch on the box that allowed us to change them from parallel (voltage) to series (current). We could run voltage OK but the series current connection had too much resistance for the calibrator to overcome if you did more than 2 or 3 (compliance voltage).  This was on older equipment, Fluke 332 for DCV, HP 745A for ACV and Fluke 760A for current.  I sometimes wonder what became of that thing, our old shop is now a vacant lot at Hood.

[USMCPMEL]

Why are you shaking your head RF cal?? If your doing no data it makes it go a heck of a lot faster. You never daisy chained a couple attenuators?? Just put like 3 of them together (same type like 20 DB) get your reding figure out the difference divide by 3 and BOOM calibrated 3 in the time it takes to do one!!

[Top Gun Test]

3 attenuators in a daisy chain ? How many issues can I state that
will happen because of this , Mismatch of impedance , VSWR , one being high
one being low , pin depth ect ect .  To many errors in that philosophy I hope that was just a joke
you where doing . Because it made me laugh and think horrible thoughts of traceability.

[CalibratorJ]

You've never daisy chained attenuators? It works great, especially on a PNA! Always try to do 4 20db ones at the same time, they always read spot on 

/end sarcasm

[CalLabSolutions]

OK.. I am going to chime in here..
Yes.. They read spot on because you are getting a average.
Metrology is about comparing an unknow to a know.  Not the average of 4 unknows to a know.  Of course they most likely going to be spot on.

And that is not the same as daisy chaining DMM's.  The Fluke calibrators will typically trip when they can't provide the source required.  Voltage can be done in parallel but the lab should know the errors or repeatability of their cables this can be done with an R&R Study. Same thing with Current except in series.  Resistance has to be tested one UUT at a time.

We automated one of our customer's labs to do DMM's in bulk they can calibrate 8 Fluke 87's in 2 hours.  With data it was $85 dollars each if you do the math that's over $300 per hour.  The only problem is feeding the monster.

Mike

[Top Gun Test]

Mike
Thanks for the chime in . Yep a auditor would have a field day with
this practice . And Yes on the 5520A daisy chain they are not understanding
about the impendance of the daisy chain and what that will do to ACV freq response .
And Yes loading effects will cause possible issue with the 5520A or whatever calibrator
you are using . Saving time and doesn't result in quality and proper traceability.
  But I guess if they want to do these practices so be it , Im not the auditor  .

[RFCAL]

I agree with cal lab solutions wholeheartedly.. OMG!!

[USMCPMEL]

I forgot I had to write "sarcasm" ayt the end of that....

[RFCAL]

Hey, you're doing this wrong! You're in a production line, not a calibration lab.

[griff61]

Real kalibraters daisy chain spec ans

[Duckbutta]

There is certainly a place for daisy chaining handhelds. It's a legitimate practice used in every lab I've ever worked in, including Air Force Type IIA. Top Gun is overstating the AC effects. We are talking low frequencies here, practically DC in the grand scheme of things. The proof is in the pudding. Daisy chain 4 Fluke 87s and take the data, then do one at a time. No discernible difference. I'm not saying that there aren't some additional uncertainties associated with this method, I'm just saying they are negligible for all intents and purposes. We are talking about a handheld DMM for the love of God. Use some common sense. The calibration only has to be "good enough" for the situation at hand. That's why we don't use 3458As to calibrate power supplies. Not every cal requires the best that you've got. If somebody told you different, someone done told you wrong. Oh, and no, I would not daisy chain attenuators under any circumstances. But that's a whole different ball of wax.