Did a lot of searching but could not find the method to calculate the formula for a new .adx value I trying to add. I have a flash PCM 16188051 $EE files and I'm trying to add A/C Evaporator Temperature F* to the values in the .adx using ADX editor. I have found that the Evap temp byte is Mode, 1 Msg 0, Word 26 on the PCM data stream and in the ADX editor I'm using offset 0X19 (hex) 25 D on the Values, Item creation screen. By experimenting with another program I have found the following.... Temp sensor wire enters the PCM on pin D24, at 0v (ground) potential on D24 the scanner reads 90* F (32.3* C) and at +5V potential on D24 scanner reads 20*F (-6.7* C) . My problem is calculating the conversion equation to display temperature in degrees F. I've understand the 5V/255 fraction but am getting confused on how I factor that into the 90-20= 70/255 fraction needed to convert the voltage to degrees. The other point is the temp display value drops as voltage increases. If so then the fraction in the equation will be negative using start point or 90* F EG:( n* -fraction +90.00) this assumption could be my problem.
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