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Kiss Analog butthurt over Dave getting free stuff

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AVGresponding:

--- Quote from: HalFET on December 02, 2023, 08:53:19 am ---
--- Quote from: Someone on December 02, 2023, 03:14:17 am ---Where have I said to use uncalibrated equipment for compliance/documentation? There are many tasks within R&D (and even in manufacturing) where there is no impact on safety or compliance, indication only. There should be no blurry for the experienced/qualified people doing such work, they should be educated well enough to be able to confidently identify what needs calibrated devices, and what the calibrations should be (not just a sticker on the front).

Gong hard on calibrating everything just in case is one way to go, it's not the best/only way to go in every situation. You're imagining some world where policy eliminates thought, which I will suggest is likely more dangerous (through people not thinking through what calibration means and applies to) than putting decision making with trustworthy people.

--- End quote ---

Ok, you do a quick measurement, now you write an e-mail with the results, a colleague quickly copies something from it for some design documentation, congratulations you just have data from an uncalibrated instrument in your design documentation. So yes, it really can get quite fuzzy because people are imperfect and make small mistakes. So it's a black and white issue from a quality manager's point of view, uncalibrated instruments have no place on the work floor. And I can perfectly understand why they're doing it, the laissez-faire approach to handling instrument tracking and calibration has filled up a few graveyards over the years. This is literally the point behind quality systems, it prevents small fuck ups from becoming big fuck ups with mindless procedures to catch mistakes that'd get glanced over otherwise. And yes, it's annoying sometimes, it can be dreadful to deal with, but if you're going to do something like stick an electric heater in a plastic enclosure you damn well want those sort of processes to be in place.

And as to, "it's fine in R&D", it really isn't. I work in R&D, if something weird happens in the field it's not uncommon for us to go on location to figure out what went wrong. Having to second guess your equipment there just ain't worth the potential cost savings.

--- End quote ---

Unthinkingly and unquestioningly trusting the reading on any piece of TE just because of a cal sticker and a brand-name is also not a sensible standpoint. Without knowledge of what a sensible reading might be, in both normal and fault conditions, and why, it's just a box-ticking exercise.

A cal sticker on a premium brand doesn't guarantee accurate results, it just indicates that reasonable steps were taken to try and ensure them.

mendip_discovery:

--- Quote from: AVGresponding on December 02, 2023, 09:04:11 am ---A cal sticker on a premium brand doesn't guarantee accurate results, it just indicates that reasonable steps were taken to try and ensure them.[/color][/font][/b]

--- End quote ---
95% probability with luck.

I often suggest customers keep a standard or two they can keep around to check the kit.

With scales it a weight, the logic being it's a simple item and means you check regularly that it's still ok. It's a bit like having a resistor or a simple voltage reference about.

Someone:

--- Quote from: HalFET on December 02, 2023, 08:53:19 am ---
--- Quote from: Someone on December 02, 2023, 03:14:17 am ---Where have I said to use uncalibrated equipment for compliance/documentation? There are many tasks within R&D (and even in manufacturing) where there is no impact on safety or compliance, indication only. There should be no blurry for the experienced/qualified people doing such work, they should be educated well enough to be able to confidently identify what needs calibrated devices, and what the calibrations should be (not just a sticker on the front).

Gong hard on calibrating everything just in case is one way to go, it's not the best/only way to go in every situation. You're imagining some world where policy eliminates thought, which I will suggest is likely more dangerous (through people not thinking through what calibration means and applies to) than putting decision making with trustworthy people.
--- End quote ---
Ok, you do a quick measurement, now you write an e-mail with the results, a colleague quickly copies something from it for some design documentation, congratulations you just have data from an uncalibrated instrument in your design documentation.
--- End quote ---
For systems I worked in, if there is documentation which requires calibration then the calibration dates+serials/identifiers are recorded against the data. Are you suggesting a quality system that assumes all items are suitable and calibrated but the chain is not auditable because the result is not linked back through traceable calibrations?

The entire point of traceable calibration is that if some discrepancy is found, every item in the chain can be checked, and resultant data produced can be marked as questionable until resolved. That should not change regardless of the percentage of calibrated equipment in circulation.

HalFET:

--- Quote from: AVGresponding on December 02, 2023, 09:04:11 am ---Unthinkingly and unquestioningly trusting the reading on any piece of TE just because of a cal sticker and a brand-name is also not a sensible standpoint. Without knowledge of what a sensible reading might be, in both normal and fault conditions, and why, it's just a box-ticking exercise.

A cal sticker on a premium brand doesn't guarantee accurate results, it just indicates that reasonable steps were taken to try and ensure them.

--- End quote ---

Come and see, come and see, we've found another person who doesn't understand the point of calibrations! If you get an odd reading on a calibrated instrument, you have a pretty good chance that what you're measuring is the thing acting up, and not the meter. Meanwhile, if I'm working with an uncalibrated instrument I quite literally have to assume that the instrument could be the thing that's acting up, and I have to pull out a second one to get some degree of certainty. And with a calibrated instrument you can, within reason, assume that the quantity you're measuring won't deviate more than a certain percentage from the actual measured quantity, which means you can actually compare measurements from various instruments over time and have a pretty good idea about what's your measurement error and what's the actual effect you're trying to measure. If you do not understand the value of that when you're debugging or designing something, then I'm at a loss for words, it's a major time and effort saver, and as a large company it's the responsible option.


--- Quote from: Someone on December 02, 2023, 11:06:02 pm ---For systems I worked in, if there is documentation which requires calibration then the calibration dates+serials/identifiers are recorded against the data. Are you suggesting a quality system that assumes all items are suitable and calibrated but the chain is not auditable because the result is not linked back through traceable calibrations?

The entire point of traceable calibration is that if some discrepancy is found, every item in the chain can be checked, and resultant data produced can be marked as questionable until resolved. That should not change regardless of the percentage of calibrated equipment in circulation.

--- End quote ---
Are you a dunce, or is risk mitigation really such a foreign concept to you?

bdunham7:

--- Quote from: HalFET on December 02, 2023, 11:20:04 pm --- Meanwhile, if I'm working with an uncalibrated instrument I quite literally have to assume that the instrument could be the thing that's acting up

--- End quote ---

Calibration certificates are not magic tokens that shield you from the possibility that your instrument may malfunction.  Your test instrument is always part of the circuit and you always have to consider that the instrument may have a fresh or previously unknown defect.  For a concrete example, if I observed an unexpected reading using my Fluke 27 (obviously quite old) I would assess the probability of the meter having a problem as extremely low, the possibilty of an issue with the test leads or setup as worth a look and the likeliehood that the anomalous reading is, in fact, correct as pretty high.  An 11-month old calibration certficiate stuck on the back wouldn't move the needle on my expectations.  Now I have the means to check it myself, something I think every critical use should require.

Personally I think the key here is generally to not use other people's instruments and to not let them use yours.  That freshly calibrated $5K LCR meter might have just been used by some idiot to test a charged reservoir capacitor in an SMPS.  The sticker won't protect it.

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