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About marciokoko

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    Hi, I am New!

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  1. PT100 on Arduino Mega Industrial Shields PLC

    Thanks ive posted there already:    
  2. Im trying to use my PT100 with an Arduino-based PLC from Industrial Shields, which is basically an Arduino Mega encased in a plastic container. Im using a 250Ω resistor, actually 237Ω resistor between Analog and Ground.  Here is my setup: Here is my code: int sensorValue = 0; int temperature = 0; int ReceivedByte = 0; float f1 = 0; float t1 = 0; void setup() {   Serial.begin(9600);   Serial.println("hi..."); } void loop() {   delay(1000);   sensorValue = analogRead(A2);   Serial.println(sensorValue);   temperature=map(sensorValue,639,719,0,110);   f1 = temperature; // Float conversion   Serial.print(f1);   Serial.print("\n"); } These are my results for room temperature: I got the values from an online pt100 table for resistance and tabulated them from 0-110C in 10 deg increments and for the corresponding resistance using: nADC = 1023 * ( 237Ω/(237Ω+Rpt100)) Its not working because im getting values of ~300 for room temp which is well below this range, but since its not constrained (the map function).  What should I do? Thanks