Subject: From: Date:

Re: [ECS] Temp items - format question Ingo Pakleppa Sun, 13 Sep 1998 16:22:34 -0400

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Nerd like you, I'd vote for rounding (not truncating) the F temperatures.

How about this: round to the nearest HALF F. You would never see two C
temperatures translate to the same F value. Plus, having increments of 0.5
would appear pleasing to the eye because the C has the same increments. Of
course, you'd still have the problem that 69.0 would be followed by 70.0
rather than 69.5, but I suppose that is more bearable than missing several
individual decimals.

Ingo

At 03:32 PM 9/13/98 -0400, Wayne wrote:
>  Mark G and I have been working on adding support for the HAI RC-xx series
>of thermostats.  I am (We are?) not sure what format the temperature items
>and set-points should be presented in.  Most of the dilema has to do with
>the 'stat serial protocol, as it is geared towards Celsius.  Here is part of
>the protocol chart:
>
>OmniUnits   C       F   (from Appendix A of serial6.doc)
>121	 20.5	 68.9
>122	 21.0	 69.8
>123	 21.5	 70.7
>124	 22.0	 71.6
>125	 22.5	 72.5
>126	 23.0	 73.4
>127	 23.5	 74.3
>128	 24.0	 75.2
>129	 24.5	 76.1
>130	 25.0	 77.0  ***
>131	 25.5	 77.9  ***
>132	 26.0	 78.8
>133	 26.5	 79.7
>134	 27.0	 80.6
>135	 27.5	 81.5  ***
>136	 28.0	 82.4  ***
>137	 28.5	 83.3
>138	 29.0	 84.2
>139	 29.5	 85.1
>140	 30.0	 86.0
>141	 30.5	 86.9
>
>   The left column is the register values, the Celsius is a simple, direct
>conversion ( (register-80)/2 = Celsius ).  Fahrenheit is the mathematical
>conversion of the Celsius, so it is not nice round numbers.  Notice that
>there are two register settings that compute to 77, if it is truncated to
>whole numbers.  If you round things, then there is a double entry at 82!
>   The physical thermostat displays WHOLE F degrees (ie 79) or HALF degrees
>C (ie 26.5).  As an engineer, it kinda goes against my nature to display a
>number such as 79.7, when the next increment is 80.6, rather than 79.8.  It
>implies a precision/accuracy that isn't really there!  Am I being too nerdy
>here?
>   At the moment, Mark has items showing as '79.7 F / 26.5 C', we have also
>considered '79.7 / 26.5' (no labels) or '79 / 26/5' (no decimal).
>   At one time, it simply displayed '79' and you had another item that would
>toggle all displays to Celsius mode.  This version had a problem where the
>ECS item didn't always match the stat display (due to rounding?).
>   I am not sure if it is better to use whole numbers (rouunded or
>truncated?) or show the true number (including decimal)?  I think that
>somewhere/somehow, we need simple numbers for speaking and testing in events.
>   Since I have only been testing on a spare Win machine without my 'stat
>actually hooked up to the A/C, I haven't written any real events to handle
>this stuff.
>
>   What do y'all think of this?  What would be the preferred format?  What
>are those of you with weather devices or other 'stats using?  This situation
>really applies to many temperature devices, not just this 'stat.  This would
>be so simple if my wife spoke Celsius!
>
>c'ya,
>Wayne
>
>   waynew 'at' magicnet 'dot' net,   Orlando, FL
>   http://www.magicnet.net/~waynew
>

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| Ingo Pakleppa            mailto:ipakleppa@ecs.com              |
| Microsoft Certified Professional + Internet                    |
| Microsoft Certified Systems Engineer                           |
| Eagle Creek Systems, Inc., P.O.Box 888, Bonsall, CA 92003-0888 |
| http://www.ecs.com                                             |
| (w) Tel.: 760 731-3251  Fax: 760 731-0054                      |
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