[aprssig] FindU Telemetry page - Help needed
Mark Cheavens mcheavens at usa.netFri Oct 10 20:52:05 UTC 2008
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Steve, Thank you very much for the refresher course in Algebra! For those interested, Here is the solution: (In the form of the needed link!) http://www1.findu.com/cgi-bin/tele1.cgi?call=PURG&last=96¶m=1&b=3.52944&c=-443.02&label=Purg_Repeater_Cabinet_Temp&units=Temperature_F&autorange=1 Now to ship it North for the "rest of the crew" to go and install it! (I a stuck WORKING in Houston!) Mark KC5EVE At 03:02 PM 10/10/2008, you wrote: >Let me guess, you learned using the new math... if it doesn't involve >apples or trains heading in opposite directions, you are lost ;-) > >First, this is also a linear system, which means that the a is zero. >For a given change in the telemetered value, the measured parameter >changed the same amount, whether the parameter change is from 99 to >100 or 1 to 2. > >Given it is linear, the formula is bx + c > >You are right, the problem is easier without converting to F, so let's >do it in C first. > >The way you wrote it is (with an extra set of parens added for clarity) > >((tele + 4.7) * 1.9608 ) - 273.15 > >it is just algebra to put this in the form bx + c > >distribute the multiplication > >((tele x 1.9608) + (4.7 * 1.9608 )) - 273.15 > >4.7 * 1.9608 is 9.215, add this to the other constant -273.15 > >that makes the centigrade formula 1.9608 x + (-263.9) > >b = 1.9608 c = -263.9 > >solving for x = 148 gives 26.3 degrees C, a reasonable room temp > >so you want F? > >F = (C * (9/5) ) + 32 > >We know C is 1.9608x - 263.9 and 9/5 is 1.8 > >F = ((1.9608x - 263.9) * 1.8) + 32 > >Just like above, you distribute the 1.8, and add the two constants to >get the b and c. This is left as an exercise for the reader. ;-) > >Steve K4HG > >On Oct 10, 2008, at 3:25 PM, Mark Cheavens wrote: > > > I am trying to work with the telemetry page on FindU. I have a > > telemetry value that requires the attached math to make it display > > the way I want. I haven't figured out how to make the math work to > > get it to display correctly. Any help would be appreciated. > > > > Sample URL: > > > http://www1.findu.com/cgi-bin/tele1.cgi?call=PURG&last=96¶m=1&b=1.0&label=Purg_Repeater_Cabinet_Temp&units=Temperature&autorange=1 > > > > I am reading telemetry parameter 1. > > > > I need to take the value (Currently sitting on my bench in an air > > conditioned room!) with a value of 148 > > > > I would LIKE to have the value in Degrees F (I know that C would be > > easier)..... > > > > So here is the formula: > > > > ((Telemetry + Correction Factor) X 1.9608 Sensor Multiplier - 273.15) > > * 5 / 9 - 32 = F > > > > For this install the correction factor is 4.7. > > 1.9608 is the sensor multiplier (Constant) > > The rest if just the basic math... > > > > OR ((148-4.7)*1.9608-273.15)*9/5+32=TempF > > > > I don't understand how the a= b= and c= can get me there! > > http://www.findu.com/cgi.html#tele1 > > > > Any help would be appreciated! > > > > (I have figured out the easy linear ones in the past - Like this same > > one for voltage - > > > http://www1.findu.com/cgi-bin/tele1.cgi?call=PURG&last=96¶m=2&b=.072254&label=Purg_Batt_Voltage&units=volts&autorange=1 > > > > (FYI - This is the output of an OpenTracker+ being used in an outdoor > > solar only radio site (Emergency Clinic) to record interior > > temperature for the batteries and battery voltage. - I do have it on > > the status line, but I don't like the resolution, and would like to > > plot it like I have done for the voltage) http://map.findu.com/purg > > > > > > Mark > > KC5EVE > > > > > > > > _______________________________________________ > > aprssig mailing list > > aprssig at lists.tapr.org > > https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig > > > > >_______________________________________________ >aprssig mailing list >aprssig at lists.tapr.org >https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
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