RTD Class B Tolerance Calculator

An RTD (Resistance Temperature Detector) is a commonly used sensor for temperature measurement in various industrial applications. Class B RTDs offer good accuracy and are widely used where extreme precision is not critical. This RTD Class B Tolerance Calculator helps you determine the permissible deviation in resistance for a specific temperature, ensuring that your RTD measurements are within the defined accuracy limits according to the DIN IEC 60751 standard.
How to Use the RTD Class B Tolerance Calculator?
- Select the RTD Type: Choose the configuration of the RTD (2-wire, 3-wire, or 4-wire) used in your application.
- Input the Temperature: Enter the temperature in degrees Celsius (°C) at which you need to calculate the tolerance.
- Calculate the Tolerance: The calculator will provide the Class B tolerance value based on the DIN IEC 60751 standard, giving you the acceptable range for the RTD’s resistance at the selected temperature.
What is the Tolerance of a Class B RTD?
The tolerance of a Class B RTD defines its accuracy at a specific temperature. This tolerance changes with temperature and is wider than that of Class A RTDs. The tolerance for a Class B RTD is calculated using the following equation:
Formula for RTD Class B Tolerance
For Class B RTDs, the tolerance is given by:
Tolerance (°C)=±(0.30+0.005×∣T∣)
Where:
- T is the temperature in degrees Celsius.
- The absolute value |T| ensures that the calculation is accurate for both positive and negative temperatures.
Example Calculation
For an RTD operating at 150°C, the Class B tolerance is calculated as:
Tolerance=±(0.30+0.005×∣150∣)°C
Tolerance=±(0.30+0.75)°C
Tolerance=±1.05°C
This means the RTD’s resistance can deviate by up to ±1.05°C from the actual temperature, and it will still meet the Class B tolerance limits.
Class B RTD Tolerance Values According to DIN IEC 60751
The following table shows the Class B RTD tolerance values according to the DIN IEC 60751 standard. These values provide the permissible deviation in temperature for different operating temperatures.
Temperature (°C) | Resistance (Ω) | Tolerance (°C) | Tolerance (Ω) |
-200 | 18.52 | ±1.30 | ±0.56 |
-100 | 60.26 | ±0.80 | ±0.32 |
0 | 100.00 | ±0.30 | ±0.12 |
100 | 138.51 | ±0.80 | ±0.31 |
200 | 175.86 | ±1.30 | ±0.49 |
300 | 212.05 | ±1.80 | ±0.65 |
400 | 247.09 | ±2.30 | ±0.88 |
500 | 280.98 | ±2.80 | ±1.08 |
600 | 313.71 | ±3.30 | ±1.27 |
650 | 329.64 | ±3.55 | ±1.36 |
Click here for RTD Class A Tolerance Calculator
Comparison Between Class A and Class B RTDs
The below table highlights the key differences between Class A and Class B RTDs in terms of tolerance, accuracy, application, and cost.
Feature | Class A RTD | Class B RTD |
Tolerance Formula | ±(0.15 + 0.0020 |T|)°C | ±(0.30 + 0.0050 |T|)°C |
Accuracy | Higher accuracy, more precise temperature measurement | Lower accuracy, suitable for general applications |
Applications | Critical applications requiring precise temperature control | General industrial use where ultra-high precision is not necessary |
Temperature Range | Suitable for a narrower, more precise temperature range | Suitable for a wider, less critical temperature range |
Cost | Typically more expensive due to higher precision | Less expensive and more commonly used |
Use Cases | Laboratory testing, precision equipment | General process control, HVAC, industrial systems |
Click here for RTD Temperature Coefficient Calculation
Applications and Benefits of RTD Class B Tolerance Calculator
- Ensures adequate accuracy for industrial applications where extreme precision is less critical.
- Aids in calibration and validation of temperature measurement instruments in general-purpose applications.
- Guarantees that your RTD measurements comply with the DIN IEC 60751 standard for Class B tolerance.
This RTD Class B Tolerance Calculator is a valuable tool for engineers and technicians who require reliable temperature measurements in non-critical environments.
Click here for RTD Tolerance Calculation
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