How does temperature compensation affect resistance-based sensors in a process environment?

• A. Temperature has no effect on resistance in sensors.
• B. Compensation eliminates the need for sensor calibration.
• C. Compensation increases the resistance drift.
• D. Temperature changes alter resistance; compensation uses a second temperature sensor or intrinsic compensation in the device to correct readings.

Answer: (D)

Temperature directly affects resistance in most conductive sensor elements. As the process temperature changes, the material’s resistance shifts even if the thing you’re measuring hasn’t changed. That drift can be mistaken for a change in the measured quantity, leading to inaccurate readings.

Compensation tackles this by bringing in a temperature reading and using it to adjust the sensor signal. This can be done with a separate temperature sensor placed near the resistance-based element, or with intrinsic compensation inside the device. The idea is to apply a correction factor so the output reflects the true value of the measured parameter independent of temperature changes. A simple way to picture it is using a linear correction like R_corrected ≈ R_measured / [1 + α (T − T_ref)], where α is the temperature coefficient.

So, temperature changes alter resistance, and compensation uses an additional temperature measurement or internal algorithms to correct the readings. This is why the other statements don’t fit: temperature does affect resistance, compensation doesn’t remove calibration needs entirely, and proper compensation reduces drift rather than increasing it.