test equipment calibration stability, older vs newer

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I have an older digital power meter and there are 21 potentiometers inside and I'm guessing the calibration is made to the analog side of
the circuit. Some newer instruments use EEPROM to store calibration offsets of other part and these have very few or no potentiometers. The stored values within the EEPROM is digital and it does not change over time and it is only changed to make an adjustment to drift of other components.
Do newer instruments using ASICs and electronic calibration offer better calibration stability in general compared to older ones made with lots of general purpose ICs, discrete components and dozens of adjustment potentiometers on the analog side?
Having a lot of discrete components and potentiometers seems like a lot more room for calibration drift.
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Are there multiple power ranges? Perhaps there are fewer pot's involved in setting each power range?
snipped-for-privacy@gmail.com wrote:

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Joe Leikhim K4SAT
"The RFI-EMI-GUY"
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New designs have several advantages:
Fewer components + many of the newer components are more temperature stable
Calibration is usually done automatically during test by applying known signals, monitoring the response and storing an adjustment value. When calibration is done with potentiometers one is relying on the test tech to do the adjustment properly and in the correct sequence. My experience has been that the test people don't always follow the proper procedure but look for short cuts to reduce the test time.
Some modern equipment does periodic self tests to verify that calibration is still good
Dan
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Dan Hollands
1120 S Creek Dr
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Dan Hollands wrote:

Perhaps *test* people do a sloppy job; a cal lab is a bit different,to say the least (worked in one got a good part of a year during a RIF period).
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Another advantage of the not pot design is that it eliminates the temptation for the customer to mess around with pots and then complain about the unit not operating properly
Dan
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Dan Hollands
1120 S Creek Dr
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Dan Hollands wrote:

That is what a calibration seal is for; proof of idiot tampering.
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I got gigged by QA the other day for using an uncalibrated decade box. (I was simulating a thermistor to test circuit and firmware response.) Out of curiosity, I popped it open - there are no adjustments whatsoever, although I guess you could trim some of the elements with a soldering iron.
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Richard Henry wrote:

But if you do not kow enough about the characteristics of each of ther brand and types of resistors used, you would not know which ones to leave alone, and which ones that *might* tolerate such abuse.
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Well, the "gig" was for using a box that didn't have a current inspection sticker.
Something like a decade box would not require frequent testing but it should be subject to some independent evaluation before being set out among the engineers and the techs as a de facto secondary standard.
And things like that need to at least be checked every now and then. It just ain't hard to "cook" a resistor without knowing it. It should only take a few minutes to ensure that every digit of every decade is "gud enuf", the contact resistance is "in the noise" and such.
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Yes, good points. Equipment can be out of spec even if it has no adjustments.
I am going crazy right now with a few Tektronix plug-ins. The 1% resistors are dead on, but the 5% ABs are drifting like crazy, out of spec by 200% to 300%. Admittedly, these problems took 25 years to develop, but, how old is the decade box in question?
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On Sat, 17 Dec 2005 21:52:35 -0800, Richard Henry wrote:

At another site we had lab inspections as part of ISO 9000 audits. For equipment that wasn't used as standards there were red "ISO-NO" stickers put in place of the calibration stickers. The one thing they really got the audit-police twisted were the calibration stickers on torque screwdrivers. Get caught with an expired sticker anywhere around customer hardware and you got your head handed to you. I haven't seen such things since I moved though.
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Keith

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