Not sure what your spray about lawyers butts, PhD's etc. has to do with the interpretation of error in conductivity measurements, your world clearly is confused.
But surely not so confused that the difference between a range and a full scale reading is not clear. You say:" It would have been easy to have stated accuracy as +/- 2% within it's intended "range" ...not "full scale". which would make full scale irrelevant, but they didn't." Yes they could have said that for single range meters, but you ignore the explanation I gave for this... "and is reported as percentage full scale (this is because some meters have more than one range and thus the full scale reading and error is altered accordingly)."...in other words the error for the range 0-99 is one tenth of the error for the range 0-999. This also has the added advantage of allowing the direct comparison between meters as to which is the most accurate. For the rest of your message I have no answer... it would be easier to just duke it out... your place or mine? Ivan -----Original Message----- From: Ode Coyote [mailto:coyote...@earthlink.net] Sent: Monday, 28 October 2002 4:52 a.m. To: *Silver-List* Subject: RE: CS>TDS/PWT meters >Hanna's spec reporting is industry standard. >Full scale and range are two different things. The range is a >description of an interval of numbers in which the unit will perform >within spec. Full scale (reading) is largest number within the range. #### You just said that range and scale are not the same thing, then, that they are. It would have been easy to have stated accuracy as +/- 2% within it's intended "range" ...not "full scale". which would make full scale irrelevant, but they didn't. Why would that be? Perhaps Industry Standard 'Reporting' is as full of butt covers as a lawyers closet. A covered butt can still toot in tune, [especially if faced off with a tuning fork before each performance] it just doesn't 'have' to. The PWT does perform as we apply it better than expected but it's far from perfect. [it's not 'just' the meter] CS is a very weird sort of water. The conductivity changes even in the same batch. The very act of measuring it seems to change it. [OK, call it stabilization. Will any two batches stabilize the same?] The PWT might be great for testing salinity. Saline solutions are pretty stable. CS? Who knows? Are we mixing our own metaphors? [Absolutely! Measuring apple sauce to see how many oranges there are.] I have not been 'happy' with ANY of the methods for measuring PPM including the various ways that labs do it. I also know it doesn't matter that much as long as we stay within a nebulous range of common sense. We're not feeding it into a computer. It doesn't take a furniture maker to adequately frame a house. I won't let something like that ruin my day. It's just no big deal..like an apple to an elephant. But it does take some explaining to those who want precise numbers and can't get them. People expect and demand certainty and tend to get certainty from people who will give it to them whether or not there really is any. Then they wonder why so many people say so many different things and why their results don't exactly match any of the statements. Not enough butt covers leads to em-bare-ass-ment? {Sure. That's the way the real weird world of comparisons works} Does PHD stand for piled high deniability? The mountain, to the ant vs the elephant, is but a matter of relative time and awareness. Neither probably gives a hoot, being focused on eating the apples and oranges found along the way. But an apple to an elephant is a morsal while it's a mountain of food to an ant. [something worth fighting over] Moral to the story: The CS you like the best is the best CS. If there's some way to make something different, 'that' may become the best CS that you like best. Batch to batch repeatability is more important than person to person comparison. In that, a Hanna meter does OK and the PWT does that better than the other Hanna meters no matter what the specs say or how they read. It would seem that everything having to do with CS is subjectively relative, CS still does what it does and it's hard to hurt yourself with it if ANY degree of common sense is employed. Common sense doesn't rely on specific numbers. Being 'more right' doesn't make anyone totally wrong. The world is clearly confused. Why not admit that nothing is what it looks like? Ken It stands to reason, then reason wobbles around its eccentricity. > > >The absolute determination of ppm as silver ions etc. may be >difficult, but the measurement of conductivity is not. Discrepancies >between different meters can be overcome by multi-point calibration >within the expected range. ## The tuning fork. If one was not used, don't even 'think' about an arguement...then think twice about apples and oranges. Discrepencies are not entirely due to the instrumentation, however, Hanna could have stated their specs without mixing them up. > > >A mountain to an ant is what to an elephant? > -- The silver-list is a moderated forum for discussion of colloidal silver. Instructions for unsubscribing may be found at: http://silverlist.org To post, address your message to: silver-list@eskimo.com Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <mdev...@eskimo.com>
