Hi Vince,

The PWT has a temperature compensator.  The s.s. tube on the left side is
the probe.  So, when calibrating just let it stabilize at whatever
temperature the solution is and then check the meter to make sure it reads
84.0 uS.  Make sure you wait until the meter stops "hunting".

Here's the calibration info on the bottle label.  You'll see that 84.0 uS is
the reading at 77 F.

°C °F   uS/cm
0   32.0   64
5   41.0   65
10 50.0   67
15 59.0   68
16 60.8   70
17 62.6   71
18 64.4   73
19 66.2   74
20 68.0   76
21 69.8   78
22 71.6   79
23 73.4   81
24 75.2   82
25 77.0   84
26 78.8   86
27 80.6   87
28 82.4   89
29 842   90
30 86.0  92
31 87.8  94

I hope this helps.

Trem



----- Original Message -----
From: "Vince Richter" <[email protected]>
To: <[email protected]>
Sent: Friday, October 10, 2003 8:13 PM
Subject: [silver_list] CS>Trem; was RE: CS>Measuring very high ppms


> Trem, since the subject came up, how much difference does the
> calibration temperature make?  I know the cal needs to be done at a
> certain temp.  Would there be a ballpark correlation between calibration
> error and temp. deviation from the standard during calibration?  Is
> there a uS per degree F deviation ballpark error (in the 10-20 uS
> range)?  The reason I ask is that I have both the PWT and the cal
> solution.  I haven't used the solution yet because I have no reason to
> believe it's out of cal.  The uS I read in my CS was within 1 ppm of the
> ppm CS Ole Bob measured.  When the time comes and I calibrate my meter,
> I wondered how meticulous I need to be, and how much difference a few
> degrees would make.
>
> Thanks, Vince
>
> -----Original Message-----
> From: Trem [mailto:[email protected]]
> Sent: Friday, October 10, 2003 4:21 PM
> To: [email protected]
> Subject: CS>Measuring very high ppms
>
>
> ----- Original Message -----
> From: "Mike Monett" <[email protected]>
> To: <[email protected]>
> Sent: Friday, October 10, 2003 1:41 PM
> Subject: [silver_list] Re: CS>Re: Measuring very high ppms
>
>
> >
> >   The Hanna PWT would be an excellent method if I could find  some way
> >   to guarantee  the calibration. Steve Young's idea to  make resistive
> >   standards might be an excellent solution.
>
> > Mike Monett
>
> Mike,
>
> The meter can easily be calibrated if you use the calibration solution
> from
> Hanna.  I got one box of 16 bottles of solution that was defective and
> Ken
> got one of the bottles.  It was the only batch I have gotten that was
> defective in many years.  I think you can generally trust the solution
> to do
> what it was intended to do....allow calibration of the PWT.
>
> It will be very difficult to use a standard resistor since the sensing
> electrodes are not easily accessible and the meter would have to be
> disassembled to get at the electronics.  Not something the average
> person
> would want to do.  And it's really not a good idea when all one has to
> do is
> use the factory solution.
>
> Trem
>
>
>
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