Hi,
An interesting thing about meters is that they are usually calibrated in the
workshop at Zero and at Full Scale. Thus they are the most accurate near
zero and near full scale and may be more or less accurate between. Any
reading between could be 'off' due to the algorith used to convert the
measurement to a readout. Also any reading could be 'off' due to various
factors such as variation of component values, ambient temperature, aging.
I guess that the 10ppm accuracy means the worst case expected at full scale
(2000ppm), after it leaves the factory. That works out to 0.5% accuracy at
fullscale, which is quite good for a cheap instrument. (imo Up to 2%
accuracy would be quite acceptable in the measured range. ) Assuming say 1%
accuracy and that the CS that you are trying to measure is about 10ppm, then
the reading could be out by about 0.1ppm. It would be good to have a look at
a calibration curve for the TDS-1 meter
Personally i would be more interested in the repeatability of the readings
which would probably depend on the temperature, electrical connections,
cleanliness of the CS container and the cleanliness of conductivity probe.
Tony
[email protected] wrote:
Hi Jay and Mike,
The thing that scares me about the TDS-1 is that the accuracy is
guaranteed at plus or minus 10 PPM. So if you are measuring a solution
of 10 PPM the meter can read anywhere from 0 to 20 PPM and still be in
spec as far as the company is concerned. Probably the wrong meter for CS
production at any cost.
Best wishes,
Andy
From: M. G. Devour
Well, Jay, there's value and there's value...
The TDS-1 from Hanna Instruments is a good bit cheaper, but it reads
from 0 to 2000 ppm. You'll be using it at the *very* bottom of its
range, which means the accuracy will not be tremendous. Sorta like
measuring grains of sand with a yardstick. Do you see what I mean?
--
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: [email protected]
Silver-list archive: http://escribe.com/health/thesilverlist/index.html
List maintainer: Mike Devour <[email protected]>
