SaM ~ Real World Example • Standard RTD Sensor • PT100 Sensor

• This RTD sensor is made of platinum, it is a standard material very stable, reproducible and resist to oxidation
• If we describe this sensor using the Calendar Van Dusen Equation, we usually have this values for the coefficients:
  • $A=3.9\times 10^{-3}{\text{°C}}^{-1}$
  • $B=-5.8\times 10^{-7}{\text{°C}}^{-2}$
  • $C=-4.2\times 10^{-12}{\text{°C}}^{-4}$
  • NOTE: We can also see the coefficent temperature $A$ as its sensitivity, but if we want a more accurate sensitivity (for example if we want a more precise accuracy at higher temperature $\overline{T}$) we might want to use the following formula:$\alpha (\overline{T})={\frac{R_{0}A+2R_{0}BT}{R_0}|}_{T=\overline{T}}$
• It is called PT100 since it is made of platinum and the its resistance value assumed at $0°\text{C}$ is $100\text{ohm}$.
  While “PT” stands for Platinum.
  • This sensor is made of platinum, it is a standard material, it is very stable, reproducible and it resist to oxidation
  • The value assumed by the PT100 at $0°\text{C}$ is called $R_0$ or nominal resistance.
    And as mention above the PT100 has a nominal resistance $R_0=100\text{ohm}$.
  • The measured value can also change if the power it’s high enough, so due to self-heating, of about $\simeq 0.5\frac{\text{°C}}{\text{mW}}$.
  • The usual temperature range of these sensors is: $[-200°\text{C}÷850°\text{C}]$.
  • So if we consider $A=3.9\times 10^{-3}{\text{°C}}^{-1}$ as its sensitivity, we have that its resistance value has range: $[22\text{ohm}÷431\text{ohm}]$.

---

Memory Card

---