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Re: Can a patch be made to update RCX400 firmware for OTA/Ambient Temp Calibration?

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  • rufusboy10
    Andrew, Not sure this will help. Remember, I have a pot attached to my sensor which I don t have. I can adjust the pot to any resistance and voltage to set the
    Message 1 of 16 , Nov 1, 2010
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      Andrew, Not sure this will help. Remember, I have a pot attached to my sensor which I don't have. I can adjust the pot to any resistance and voltage to set the ambient temperature. I can make a curve based on voltage and temperature to the A to D in the ltc1286 if you like. Knowing what I have available is there a test you need in order to see the digital bytes coming to you?

      Thanks
      Dale

      --- In RCX400@yahoogroups.com, "johansea" <johansea@...> wrote:
      >
      > Gday Dale
      >
      >
      > --- In RCX400@yahoogroups.com, "dale" <ddidomenico@> wrote:
      > >
      > > Sure....If you get a chance, send me the details of the test
      > > you want to astromiester1@
      >
      > Its simple enough ( i think )
      > On the handbox you can set the Dewheater to a Temperature or a Percentage mode.
      > Try setting each mode and seeing what data comes back accordingly.
      > The code appears to operate differently based on which mode you are in.
      >
      > Andrew Johansen Melbourne Australia
      >
    • johansea
      Gday Dale ... Wont help All we can get at via a patch is a word var coming back along an aux type line from a PIC somewhere . That PIC is doing the raw
      Message 2 of 16 , Nov 1, 2010
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        Gday Dale

        --- In RCX400@yahoogroups.com, "rufusboy10" <ddidomenico@...> wrote:
        >
        > Remember, I have a pot attached to my sensor which I don't have.

        ????????????? :-) ( Its early, but that has thrown me )

        > I can adjust the pot to any resistance and voltage to set
        > the ambient temperature. I can make a curve based on voltage
        > and temperature to the A to D in the ltc1286 if you like.

        Wont help
        All we can get at via a patch is a word var coming back along an aux type line from a PIC "somewhere". That PIC is doing the raw reading.
        The only code in the firmware "that we can see" converts this word to a temperatire using a function that ( i assume ) matches the sensors.

        > Knowing what I have available is there a test you need in
        > order to see the digital bytes coming to you?

        The test i wanted is the test in each mode, ( % and differential ) to see if you get different results.

        Andrew
      • dale
        Hmmmmmm... I would say no for the ambient sensor for obvious reasons, but the OTA sensor I do have and could gather data for you to generate an average offset
        Message 3 of 16 , Nov 3, 2010
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          Hmmmmmm... I would say no for the ambient sensor for obvious reasons, but the OTA sensor I do have and could gather data for you to generate an average offset value to test out if you like. I can provide ambient from my weather station and measure the inside OTA temp with a laser temp gun to gather an average offset to add to the patch if possible. Currently I estimate the OTA sensor reports -8 deg C cooler than what it really is. Once, I get you the data, I most likely will try to correct the offset via hardware by adjusting the pull up resistor with a pot on the analog input of the sensor. One way or the other we will get there.

          Thanks
          Dale

          --- In RCX400@yahoogroups.com, "johansea" <johansea@...> wrote:
          >
          > Gday Dale
          >
          > --- In RCX400@yahoogroups.com, "rufusboy10" <ddidomenico@> wrote:
          > >
          > > Remember, I have a pot attached to my sensor which I don't have.
          >
          > ????????????? :-) ( Its early, but that has thrown me )
          >
          > > I can adjust the pot to any resistance and voltage to set
          > > the ambient temperature. I can make a curve based on voltage
          > > and temperature to the A to D in the ltc1286 if you like.
          >
          > Wont help
          > All we can get at via a patch is a word var coming back along an aux type line from a PIC "somewhere". That PIC is doing the raw reading.
          > The only code in the firmware "that we can see" converts this word to a temperatire using a function that ( i assume ) matches the sensors.
          >
          > > Knowing what I have available is there a test you need in
          > > order to see the digital bytes coming to you?
          >
          > The test i wanted is the test in each mode, ( % and differential ) to see if you get different results.
          >
          > Andrew
          >
        • dale
          I think we have a winner...The sensor seems to be a surface mount SOT 23 package with output profile 10mv/deg C temp sensor from micro-chip part number
          Message 4 of 16 , Nov 3, 2010
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            I think we have a winner...The sensor seems to be a surface mount SOT 23 package with output profile 10mv/deg C temp sensor from micro-chip part number TC1047A. To verify the temperature to voltage curve, I need someone to measure an output voltage from the sensor on the board to the A/D LTC1286 pin and report the voltage and ambient temperature in which it was recorded. I can then verify it is the true part. It costs 0.84 cents each from digikey. Use a thermometer to measure the ambient temp not the keypad as we already know it needs to be calibrated to ambient. If for some reason the keypad matches your thermometer, then by all means report that too.

            We have a two fold goal here. 1. To find the part for ambient temp and 2. To calibrate the sensor to the keypad via software or hardware fix. This will apply to LX200gps models and RCX400gps models.

            Thanks
            Dale



            --- In RCX400@yahoogroups.com, "dale" <ddidomenico@...> wrote:
            >
            > Hmmmmmm... I would say no for the ambient sensor for obvious reasons, but the OTA sensor I do have and could gather data for you to generate an average offset value to test out if you like. I can provide ambient from my weather station and measure the inside OTA temp with a laser temp gun to gather an average offset to add to the patch if possible. Currently I estimate the OTA sensor reports -8 deg C cooler than what it really is. Once, I get you the data, I most likely will try to correct the offset via hardware by adjusting the pull up resistor with a pot on the analog input of the sensor. One way or the other we will get there.
            >
            > Thanks
            > Dale
            >
            > --- In RCX400@yahoogroups.com, "johansea" <johansea@> wrote:
            > >
            > > Gday Dale
            > >
            > > --- In RCX400@yahoogroups.com, "rufusboy10" <ddidomenico@> wrote:
            > > >
            > > > Remember, I have a pot attached to my sensor which I don't have.
            > >
            > > ????????????? :-) ( Its early, but that has thrown me )
            > >
            > > > I can adjust the pot to any resistance and voltage to set
            > > > the ambient temperature. I can make a curve based on voltage
            > > > and temperature to the A to D in the ltc1286 if you like.
            > >
            > > Wont help
            > > All we can get at via a patch is a word var coming back along an aux type line from a PIC "somewhere". That PIC is doing the raw reading.
            > > The only code in the firmware "that we can see" converts this word to a temperatire using a function that ( i assume ) matches the sensors.
            > >
            > > > Knowing what I have available is there a test you need in
            > > > order to see the digital bytes coming to you?
            > >
            > > The test i wanted is the test in each mode, ( % and differential ) to see if you get different results.
            > >
            > > Andrew
            > >
            >
          • Daniel Lajeunesse
            The sensor could also be a National Semi LM60B. It has a 6.25mV/C slope with a -25C to 125C range. This may be where the 25C offset is coming from - being that
            Message 5 of 16 , Dec 2, 2010
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              The sensor could also be a National Semi LM60B. It has a 6.25mV/C slope with a -25C to 125C range. This may be where the 25C offset is coming from - being that a 0 value returned would be -25C.

              Dan

              --- In RCX400@yahoogroups.com, "johansea" <johansea@...> wrote:
              >
              > Gday Dale/Dick
              >
              > Not sure where its all generated, as the data just comes back via an Aux call from ( I guess ) something in the OTA.
              > The RCX temp reading function appears to use a complex equation to convert the returned data, but it does have a 25degC base offset added to it along the way, hence it could be patched for a common offset error.
              > However, the function that does this is also tied int the dew heater operation mode etc, so i dont know what effects that may have.
              > Would need more digging to see what happens there.
              >
              > Andrew Johansen Melbourne Australia
              >
              > --- In RCX400@yahoogroups.com, "autostaretx" <rseymour@> wrote:
              > >
              > > --- In RCX400@yahoogroups.com, "dale" <ddidomenico@> wrote:
              > > >
              > > > This is a Dick Seymour question. I noticed the other day my OTA
              > > > reading was 3 degrees below ambient. A calibration entry for the
              > > > ambient would be useful that could be applied to both sensors.
              > > >
              > > > Dick, did Meade give out the source used for your patch updates or
              > > > did you dissasemble their code to op-codes by reverse engineering
              > > > approach?
              > >
              > > Patches are done by disassembly.
              > > Since the original programs were written in some higher language,
              > > (which we don't have or see or create) the view we (Andrew writes patches, too.. better ones) have of the workings all-too-frequently involve "leaps of faith" (translation: guesswork as the thread disappears into a heap of spaghetti...).
              > >
              > > Unfortunately, we're concentrating our efforts in the areas affecting alignment and GoTo accuracy (Andrew's making breakthroughs on solving the 2-star alignment bug), so Ambient Calibration may take a while.
              > > But i'll take a quick look at it. (if memory serves, Andrew worked out the equation they're using (in the LX200gps) a year ago... so part of the "look" is digging into archived messages).
              > >
              > > Question: is it *always* 3 degrees low (hence "add a fixed offset"), or is the slope of the temperature different from their expectations?
              > > (i.e. "3 degrees low at 32F, but only 2 degrees low at 50F")
              > > (hence, a multiplier coefficient).
              > >
              > > have fun
              > > --dick
              > >
              >
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