Hi Al, When accuracy is stated as +/- 2% of full scale it means that the accuracy is that percentage of full scale at ANY reading. It is NOT proportionate as some people like to think. So, if using the PWT meter as an example and the reading is 10, the actual measurement could be anywhere from 8 to 12. The TDS-1 has an inherent accuracy of +/- 10 PPM rather than a specific percentage of full scale so you can see how inaccurate that meter is for measuring ionic silver. Especially since it only reads about half of the actual content. The DIST series have accuracy of +/- 2% but once again, they read from 0-999 or 0-1999 so they can also be quite way off at the low end.
I discussed and confirmed this with Hanna Instruments technical staff. I hope this helps you. Trem [email protected] www.silvergen.com ----- Original Message ----- From: "Al Davis" <[email protected]> To: <[email protected]> Sent: Tuesday, April 06, 2004 11:57 PM Subject: [silver_list] Re: CS>PWT and TDS readings > Hi Trem, > > You wrote: > > > Most of the Hanna TDS instruments have ranges of 0-999 PPM or > > 0-1999 with 2% accuracy of full scale. That means the unit can be off by > > as much as 20 or 40 PPM at the low OR high end of the range or at any > > reading. > > How can it be off 20 or 40 PPM at a reading of 1PPM ? Or even 10 PPM? > I think the accuracy statement means 2% @ full scale, not OF full scale. > > My PWT accuracy statement says +/- 2% Full Scale. > > Al D. > > > -- > The Silver List is a moderated forum for discussing Colloidal Silver. > > Instructions for unsubscribing are posted at: http://silverlist.org > > To post, address your message to: [email protected] > Silver List archive: http://escribe.com/health/thesilverlist/index.html > > Address Off-Topic messages to: [email protected] > OT Archive: http://escribe.com/health/silverofftopiclist/index.html > > List maintainer: Mike Devour <[email protected]> > >
