Yes, it is true that calibrating a temperature indicator for only a portion of the associated thermocouple's temperature range can improve resolution. Here's how it works

Resolution:

Resolution refers to the smallest measurable change in the measured variable (in this case, temperature). A higher resolution means that the indicator can detect smaller temperature variations.

Calibration Range

When calibrating a temperature indicator, a specific temperature range is selected. This range typically covers the most commonly used operating temperatures for the temperature indicator.

Linearization

During calibration, the temperature indicator is adjusted to display accurate temperature readings within this specified range. This process involves linearizing the indicator's response, meaning that the output (display reading) is directly proportional to the input (thermocouple signal) within the calibration range.

Improved Resolution

By limiting the calibration range, the linearization process becomes more precise over a narrower temperature span. This is because the indicator focuses on achieving high accuracy within the most critical temperature range for the application.

How it Works

When the temperature indicator is used outside the calibrated range, the linearization becomes less accurate. However, within the calibrated range, the indicator can provide highly precise and repeatable temperature readings with a higher resolution due to the optimized linearization.

Example:

Suppose you have a temperature indicator and thermocouple with a temperature range of 0 to 1000°C. If you calibrate the indicator for the range of 100 to 200°C, it will have higher resolution within this narrower range, enabling it to detect and display temperature changes of smaller magnitudes. Flag for review