;Linearisation Algorithm for PT100 sensors. ;Language: Venom-SC ;Author: Karl Lam 14/02/2007 ;Copyright Micro-Robotics Ltd 2007. ; Checked for compatibility with Venom 2 ;This is a function that will 'calibrate' the non-linear PT100 ;resistance/temperature curve. Different data tables, based on different ;national/international standards, can be built. Please contact us for ;details. ;Find temperature of PT100 Sensor given resistance value 'Res'. ;Uses Array below. No range checking done. To Temperature(Res) Local Ind,ResOver10 Local T1,T2 ResOver10 := Res / 10.00;Useful intermediate result. Ind := ResOver10 As Int ;Find an index into the array T1 := PT100_data.(Ind) ;Find the Temperature at the lower Res boundary T2 := PT100_data.(Ind+1);Find the Temperature at the upper Res boundary Return T1 + (T2 - T1) * (ResOver10 - Ind);Interpolate temperature. End ;Linearisation data for PT100 sensor between -200C and +266C. ;Temperature vs. Resistance at 10 Ohm intervals, between '10' and 200 Ohms. ;Using linear interpolation, the maximum interpolation error is ; < +0.053C over the whole range ; < +0.031C above -60C. ;Contact M-R if you need data for more accuracy, or higher/ lower temperatures. ;Source Data: IEC751: ; Rt = R0[1+At+Bt^2+Ct^3(t-100)] ; A 3.9083E-03 ; B -5.7750E-07 ; C -4.1830E-12; [C is 0.000 for T >= 0.000 Deg C]. ; R0 100.000 Ohms ; Not valid for temperatures below -200C. Array PT100_data(1.0,21) -1000.00, ;0 ;Dummy value -219.537, ;10 ;This is below the specified range of PT100, included to extend to -200C. -196.574, ;20 -173.158, ;30 -149.335, ;40 -125.144, ;50 -100.631, ;60 -75.827 , ;70 -50.770 , ;80 -25.488 , ;90 0.0000 , ;100 25.684 , ;110 51.564 , ;120 77.650 , ;130 103.943 , ;140 130.446 , ;150 157.169 , ;160 184.115 , ;170 211.289 , ;180 238.698 , ;190 266.348 , ;200 End