;====== Thermistor temperature measurement ============= ;Disclaimer: ; This is an example program supplied "as is" with no warranties ; implied or express as to its suitability for any application. ; You must integrate this code into your own program and thoroughly ; test it. ;Incorporating this code into your program (general instructions) ; Only code between ;vvvvvvvvvvvvvv and '^^^^^^^^^^^^^^ is intended ; to be used in your program. Everything else is documentation and ; test code. ; If the program contains an NVEM0 directive, the stuff below that ; must be appended at the end of your program, after one single NVEM0 ; directive. ; The example code is designed to run under MultiTrack. You must ; make sure to include LaunchTask instructions to make it run. ; You need to understand MultiTrack. It is quite simple to comprehend ; and will save you a lot of effort in the long run. ; MultiTrack is previewed in a MiniTutorial within SPLat/PC ; and covered in detail in the SPLat Knowledge Base. ; Accessing the functionality from your program: ; ; All external access to the function is via subroutine calls (GoSub). In keeping ; with the ideas of object oriented programming we refer to Properties ; and Methods. ; - Properties are data you can GET or SET. The data belongs ; to the function so you are only allowed to access it through subroutine ; calls to the applicable GET or SET routine. ; ; Example: GoSub XYZ_GET_RunStatus ; GoSub XYZ_SET_RequiredLevel ; ; - Methods do something. You invoke them by subroutine calls. ; ; Example: GoSub XYZ_TurnOnPump ; ; All property and method calls have names ; starting in the short name of the function (XYZ_ above). By convention the short name ; is in upper case, very few letters and unique to the function. It ends ; in an underscore. The short name is NOT included in the property and ; method descriptions below but must be included when you use them. ; ; The startup method is usually invoked by a LaunchTask rather than a GoSub. ; ; Examples: LaunchTask XYZ_Start ; or ; LaunchTask XYZ_Init ************* Test code ********************* ;stscale 200 LaunchTask THM_Init,0 LaunchTask THM_Init,1 ; LaunchTask TestTime RunTasksForever ;vvvvvvvvvv Start of the actual example code vvvvvvvvvvv ;========== Thermistor temperature measurement (multi-channel) ================== ;Short name THM_ ;What it does: ; Temperature measurement ; ----------------------- ; THM_ provides thermistor temperature measurement. It is capable of ; handling several channel using jndexing, providing the thermistors ; are on contiguously numbered analog inuts and all thermistors use the same ; drive voltage and linearization polynomial. The result can be in 'C or 'F ; ; Low pass filtering ; ------------------ ; The results are filtered through a single pole simulated RC filter with a time constant ; of 2 seconds. ; You can change the time constant quite simply by editing two lines of code. ; ; Selecting 'C or 'F ; ------------------ ; The calculations are all done in 'C. However the final result ; can be converted to 'F by provided code in THM_GET_Temperature ; ; Processor load leveling ; ----------------------- ; The calculations required take quiate a lot of processor time, about 5mS per channel. ; In order to prevent all channels being calculated in one run of the task queue, ; (and hence generating a momentarily very long latency for other tasks). ; a token is used to stagger the channels's calculations relative to each other. ; Manual editing ; -------------- ; Lines/areas requiring manual editing are flagged with ;<<<<< ; * You must manually edit the I/O assignments to match your controller hardware. ; * Lines with mEQU use absolute RAM allocations. You MUST move these to the start ; of the program before any defXXX directives. ;---- Properties and methods --------- ;Methods: ; Init ;Initializes the background task. Invoke with 'LaunchTask THM_Init' ;Property SETs: None ;Property GETs: ; ; GET_Temperature Returns in W the filtered temperature reading for the channel number in I ; *** NB **** Don't forget to set I before calling THM_GET_Temperature!!!!!!! ;Revision history (newest on top) ; ;V1.0 060828 Initial release fTHM_Temperature defFLOAT 3 ;<<<<<<<<<<<< Edit for however many thermistors you are using fTHM_InstTemp defFLOAT 3 ;<<<<<<<<<<<< Edit for however many thermistors you are using aTHM_Thermistor EQU 0 ;<<<<<<<<<<<< Edit for your hardware: the first thermistor channel sTHM_Token defSEM THM_Init: LoadX 95 ;<<<<<<<<<<<<< Edit for selected polynomial AnOutF ;<<<<<<<<<<<<< Edit to suit hardware Pause 100 ;Allow analog output to settle fAnIn aTHM_Thermistor GoSub THM_PolyCalc fStore fTHM_Temperature ;Bypass filter for the very first reading THM_Loop: Pause 10 ;100mS between samples NoJ:WaitForSF sTHM_Token ;Wait until other channel(s) are finished NoJ:SetS sTHM_Token ;Block other channels fAnIn aTHM_Thermistor ;Read the thermistor GoSub THM_PolyCalc ;Convert to 'C fStore fTHM_InstTemp ;Save instantaneous value YieldTask ;Take a break before doing filtering fRecallW fTHM_Temperature ;Start of filter fLoadQ 19 ;<<<<<<<<<<<<<<<<<< Edit to change filter time constant fMul ; 19* accumulated value fRecallQ fTHM_InstTemp fAdd ; 19*Old + New fLoadQ 0.05 ;1/20 <<<<<<<<<<<<<<<<<< Edit to change filter time constant fMul fStore fTHM_Temperature ;New filtered value YieldTask ;Take a break NoJ:ClrS sTHM_Token ;Let other channel(s) have a go GoTo THM_Loop ;------ Polynomial calculation. Convert normalized analog reading in W to degrees C. ;I have two version here for different thermistor configurations (different polynomials). ;You will almost certainly have to use a thermistor spreadsheet to establish your ;own polynomial. You want ThermstrNorm.xls or ThermstrHVAC.xls. These work on normalized ;analog readings from the fAnIn instruction. ;Polynomial for R25=10K, Rf=33K B=3877, T= -40'C to + 50'C ;'C = -6.540441E+02x^5 + 1.871267E+03x^4 - 2.160023E+03x^3 + 1.265438E+03x^2 - 4.497268E+02x + 8.502783E+01 ;With 10-bit fAnIn resolution is better than 0.2'C -40'C to +40'C fTHM_Scratch defFLOAT ;;;THM_PolyCalc: NoJ:fStore fTHM_Scratch fLoadQ -6.540441E+02 ;<<<<<<<< X^5 coefficient fMul fLoadQ +1.871267E+03 ;<<<<<<<< X^4 coefficient fAdd NoJ:fRecallQ fTHM_Scratch fMul fLoadQ -2.160023E+0 ;<<<<<<<< X^3 coefficient fAdd NoJ:fRecallQ fTHM_Scratch fMul fLoadQ +1.265438E+03 ;<<<<<<<< X^2 coefficient fAdd NoJ:fRecallQ fTHM_Scratch fMul fLoadQ -4.497268E+02 ;<<<<<<<< X^1 coefficient fAdd NoJ:fRecallQ fTHM_Scratch fMul fLoadQ +8.502783E+01 ;<<<<<<<< X^0 coefficient fAdd Return ;Polynomial for R25=10K, Rf=10K B=3877, T= +10 to +50 (Trainer board) ;'C = -7.092727E+01x5 + 2.806945E+02x4 - 4.793233E+02x3 + 4.418513E+02x2 - 2.752315E+02x + 1.128212E+02 ;With 8-bit fAnIn resolution is b0.25 THM_PolyCalc: NoJ:fStore fTHM_Scratch fLoadQ -7.092727E+01 ;<<<<<<<< X^5 coefficient fMul fLoadQ +2.806945E+02 ;<<<<<<<< X^4 coefficient fAdd NoJ:fRecallQ fTHM_Scratch fMul fLoadQ -4.793233E+02 ;<<<<<<<< X^3 coefficient fAdd fRecallQ fTHM_Scratch fMul fLoadQ +4.418513E+02 ;<<<<<<<< X^2 coefficient fAdd NoJ:fRecallQ fTHM_Scratch fMul fLoadQ -2.752315E+02 ;<<<<<<<< X^1 coefficient fAdd NoJ:fRecallQ fTHM_Scratch fMul fLoadQ +1.128212E+02 ;<<<<<<<< X^0 coefficient fAdd Return ;------ Property GET(s) -------------- ;Get the temperature reading for the channel in I ****** Remember to set I ************* THM_GET_Temperature: IasJ:fRecallW fTHM_Temperature ;<<<<<<<< The following converts to degrees F, if that's your thing fLoadQ 1.8 ;<<<<<<<< Remove if you want degrees C fMUL ;<<<<<<<< Remove if you want degrees C fLoadQ 32 ;<<<<<<<< Remove if you want degrees C fAdd ;<<<<<<<< Remove if you want degrees C Return ;^^^^^^^^^^ End of the actual example code ^^^^^^^^^^^^^ ;------------------- LoopCounter defBYTE LoopTimer defTIME24 TestTime: ;Measure how fast MultiTrack cycles through the task queue STStart LoopTimer TT1: YieldTask DMGNZ LoopCounter,TT1 fSTTimeSince LoopTimer fLoadQ 0.0256 fSwap fDiv fLoadQ -545 fAdd OBLCD_SetCur 2,0 OBLCD_fDispW 6,0 OBLCD_Text 228,"S/Q" fRecallW fTHM_Temperature OBLCD_SetCur 0,0 OBLCD_fDispW 5,5 fAnIn 0 OBLCD_Text " " OBLCD_fDispW 5,5 GoTo TestTime