Strange Results in Math

[CocaColaKid]

I'm completely stumped on this one. I read 5 temperature sensors, convert the data read in ºC, ºF and K. Seems straight forward until I start doing the math. This is what I get on the output

+026.37ºC  +079.47ºF  +299.52 K
+026.37ºC  +079.47ºF  +299.52 K
+026.37ºC  +079.58ºF  +299.58 K
+026.37ºC  +079.92ºF  +299.77 K
+026.37ºC  +079.81ºF  +299.71 K

I can't figure why there is a difference in the numbers when they are all calculated from the same subroutine. Any ideas?

DEFINE  LOADER_USED 1DEFINE  OSC 16
DEFINE  HSER_BAUD 9600
DEFINE  HSER_CLROERR 1
DEFINE  HSER_RCSTA 90h
DEFINE  HSER_TXSTA 24h

@ __CONFIG _CONFIG1H, _OSCS_OFF_1H & _HSPLL_OSC_1H
@ __CONFIG _CONFIG2L, _BOR_ON_2L & _PWRT_ON_2L & _BORV_45_2L
@ __CONFIG _CONFIG2H, _WDT_ON_2H 
@ __CONFIG _CONFIG4L, _STVR_ON_4L & _LVP_OFF_4L & _DEBUG_OFF_4L

    data_bit        var     bit             ' Bit shift variable if not using lookup table
    sensor_error    var     bit             ' Sensor CRC error indicator flag
    sign_c          var     byte            ' +/- Sign for celcius temperature
    sign_f          var     byte            ' +/- Sign for fahrenheit temperature
    dummy           var     word            ' Dummy variable for DIV32 function
    x               var     byte            ' Loop counter
    i               var     byte            ' Loop counter
    byte_in         var     byte            ' Temporary holder for byte received from DS18B20
    data_byte       var     byte            ' Byte to perform CRC calculations on
    dq              var     byte[9]         ' 9 Byte Arrray for DS18B20
    crc_calc        var     byte            ' Calculated CRC value
    neg_bit         var     raw_temp.Bit11  ' Sign-Bit for +/- Temp. 1 = Below 0 deg C
    raw_temp        var     word            ' Raw Temperature
    temp_c          var     word            ' Temperature in ºC
    temp_f          var     word            ' Temperature in ºF
    temp_k          var     word
    sign_c_array    var     byte[5]
    sign_f_array    var     byte[5]
    temp_c_array    var     word[5]
    temp_f_array    var     word[5]
    temp_k_array    var     word[5]
    crc_error       var     byte            ' Loop counter for CRC errors
    a               var     byte
    
    clear

main:
    for a = 0 to 4
    temp_c = 0
    temp_f = 0
    temp_k = 0
    dummy = 0
    dq = 0
    gosub read_temp
    sign_c_array[a] = sign_c
    sign_f_array[a] = sign_f
    temp_c_array[a] = temp_c
    temp_f_array[a] = temp_f
    temp_k_array[a] = temp_k
    next a
    gosub display
    goto main

read_temp:
    owout a,1,[$CC,$44]                 ' Send start temperature conversion command
    low portb.5                         ' Turn on transistor between rail and data pin
    pause 750                           ' Allow enough time to process Tconv
    high portb.5                        ' Turn off transistor between rail and data pin
    owout a,1,[$CC,$BE]                 ' Send read scratch pad command
    owin a,0,[STR dq\9]                 ' Read all 9 bytes and store them in dq array
    raw_temp.Byte0 = dq[0]              ' Isolate raw temperature from the rest
    raw_temp.Byte1 = dq[1]
    gosub convert_temp                  ' Convert raw data into real temperatures
    return
    
convert_temp:
    if neg_bit = 1 then below_zero		' If below 0ºC then goto different subroutine
    sign_c = "+"                        ' Display + symbol for negative temp
    sign_f = "+"                        ' Display + symbol for positive temperature
    dummy = 625 * raw_temp              ' Multiply to load internal register with 32-bit value
    temp_c = DIV32 100                  ' Divide internal register by 10 to calculate precision ºC
    dummy = 0
    dummy = 1125 * raw_temp             ' Multiply to load internal register with 32-bit value
    temp_f = DIV32 100                  ' Make it manageable
    temp_f = temp_f + 3200              ' Make it into ºF
    gosub kelvin
    return

below_zero:
    sign_c = "-"                        ' Display - symbol for negative temperature
    sign_f = "+"                        ' Display + symbol for positive temperature
    dummy = 0
    raw_temp.byte0 = raw_temp.byte0 ^ 255
    raw_temp.Byte1 = raw_temp.byte1 ^ 255
    dummy = 625 * raw_temp + 1         ' Multiply inversion to load internal register with 32-bit value
   	temp_c = DIV32 100                  ' Divide internal register by 100 to calculate precision ºC
    temp_f = (temp_c + 5000) * 900      ' Multiply to load interal register with 32-bit value
    temp_f = DIV32 500                  ' Divide internal register by 500
    if raw_temp >= 285 then             ' Check if temperature is + or - ºF
        temp_f = temp_f - 12200         ' Process if temperature is to be negative
        sign_f = "-"                    ' Display a - symbol for negative temperature
        else				
        temp_f = 12200 - temp_f         ' Process if temperature is to be positive
        sign_f = "+"                    ' Display + symbol for a positive temperature
	endif
    gosub kelvin
	return

display:
    hserout [sign_c_array[0],dec3 temp_c_array[0]/100,".",dec2 temp_c_array[0]//100,186,"C  ",sign_f_array[0],dec3 temp_f_array[0]/100,".",dec2 temp_f_array[0]//100,186,"F  +",dec3 temp_k_array[0]/100,".",dec2 temp_k_array[0]//100," K",10]
    hserout [sign_c_array[1],dec3 temp_c_array[1]/100,".",dec2 temp_c_array[0]//100,186,"C  ",sign_f_array[1],dec3 temp_f_array[1]/100,".",dec2 temp_f_array[1]//100,186,"F  +",dec3 temp_k_array[1]/100,".",dec2 temp_k_array[1]//100," K",10]
    hserout [sign_c_array[2],dec3 temp_c_array[2]/100,".",dec2 temp_c_array[0]//100,186,"C  ",sign_f_array[2],dec3 temp_f_array[2]/100,".",dec2 temp_f_array[2]//100,186,"F  +",dec3 temp_k_array[2]/100,".",dec2 temp_k_array[2]//100," K",10]
    hserout [sign_c_array[3],dec3 temp_c_array[3]/100,".",dec2 temp_c_array[0]//100,186,"C  ",sign_f_array[3],dec3 temp_f_array[3]/100,".",dec2 temp_f_array[3]//100,186,"F  +",dec3 temp_k_array[3]/100,".",dec2 temp_k_array[3]//100," K",10]
    hserout [sign_c_array[4],dec3 temp_c_array[4]/100,".",dec2 temp_c_array[0]//100,186,"C  ",sign_f_array[4],dec3 temp_f_array[4]/100,".",dec2 temp_f_array[4]//100,186,"F  +",dec3 temp_k_array[4]/100,".",dec2 temp_k_array[4]//100," K",10,10]
    return    

kelvin:
	if sign_c = "-" then
    	temp_k = 27315 - temp_C
        else
    	temp_k = temp_c + 27315
  	endif
  	return
END

[CocaColaKid]

It would probably help if I entered the array properly in the serial output line.

[Darrel Taylor]

Hi CCK,

I know you probably want to fix what you have. But why re-invent the wheel.

Temperature Conversion (for Picbasic Pro)
http://www.pbpgroup.com/modules/wfse...p?articleid=18
<br>

[CocaColaKid]

The wheel isn't being re-invented, just made using a different process

[Darrel Taylor]

Fair enough!

I'll just keep begging everyone else. Eventually, someone will try my program.
<br>

[Luciano]

Fair enough!

I'll just keep begging everyone else. Eventually, someone will try my program.
<br>

Hi Darrel,

To link people to your version of the re-invented wheel, why don't you
put the URL of your site www.pbpgroup.com at the bottom of your posts?
(Automatic signature).

Best regards,

Luciano

[Darrel Taylor]

And steal all the picbasic.co.uk users for my super impressive, emotionaly moving website that has affected 10's of people.

Naaaa!