The main purpose of a calibration procedure is to:

The primary purpose of a calibration procedure is to adjust instruments to ensure their measurements are accurate and consistent with a recognized standard. Calibration involves comparing the output of an instrument to a known reference point, usually established by a calibration standard, and then making necessary adjustments to align the instrument's readings with this standard. This process is crucial for maintaining the integrity of measurements within control systems and ensuring reliability and safety in operations.

While testing response time, readjusting the range, and verifying circuit function are important aspects of instrument maintenance and operation, they do not encompass the fundamental objective of calibration, which is primarily concerned with ensuring the accuracy and precision of measurements in relation to established benchmarks. This ensures that the instruments properly reflect the physical quantities they are intended to measure, facilitating effective monitoring and control.