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Subject: Hygrothermographs

Hygrothermographs

From: June Wheeler <june_wheeler>
Date: Monday, July 27, 1998
Will Jeffers <wjeffers [at] mfa__org> writes

>Sean Harrison <seanh [at] experience__org> writes
>
>>Looking for some comparative field responses on the following
>>hygrothermographs:
>> ...
>>    ACR SmartReader 2 Temperature and Humidity Data Logger
>...
>Another option are the Hobo loggers marketed by Onset corporation.
>They cost considerably less (about the cost of an ACR probe!), so
>that you can employ many of them at a considerably lower cost than
>either the ACR or the Veriteq.  They advertise an RH accuracy of +/-
>3%, comparable to the Smartreader Plus line of loggers.

Just as clarification, I wanted to point out a detail related to
Will Jeffer's posting on Hygrothermographs and accuracy of % RH.  My
understanding (admitting up front that I represent ACR SmartReader
dataloggers) is that most logger manufacturers spec RH accuracy only
at 75 deg. F.  Since some dataloggers use temperature compensation
equations (in many cases, quite complex) and some do not, those that
do not can only guarantee accuracy at "room temperature".

In particular, my understanding (based upon inquiries done 5 years
ago) is that the HOBO, while a cost bargain in the datalogger world,
does not hold anywhere near a 3% accuracy above and below 75 deg. F.
The SmartReader is programmed with a very precise temperature
compensation routine which allows it to claim +/- 3% over the span
of its specified ranges : -40 to 158 deg. F and 10 - 90% RH.  This
is as good as the technology can do at this stage of development.
*Please* correct me if I am off the mark.

Please also note that the folks at ACR are currently working on a
"major revision" software release which will hopefully address
Will's and others criticisms, and this is due out yet this year (I
hope!).

One last note - I regret to say I am no longer a Veriteq dealer, and
this decision was my own to make based upon some personal
misgivings.  My apologies to those who want to acquire that product
through Herzog/Wheeler - best to contact Veriteq directly.

June Wheeler, Partner
Herzog/Wheeler & Associates

                                  ***
                  Conservation DistList Instance 12:13
                 Distributed: Wednesday, July 29, 1998
                       Message Id: cdl-12-13-002
                                  ***
Received on Monday, 27 July, 1998

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