Reconciling Divergent Calibration Certificates across Accredited Testing Facilities
Reconciling divergent calibration certificates requires auditing lab scopes, matching test conditions, and computing normalized error ratios before retesting.
RTD Calibration
Thermal Verification
Process of comparing a resistance temperature detector against a reference thermometer at known temperatures to determine its accuracy. Technicians perform rtd calibration to establish the relationship between the electrical resistance of the platinum element and the actual temperature. This procedure ensures that the sensor meets the tolerance requirements of standards like IEC 60751.
It provides the correction factors used in high precision industrial controllers. Data from the test are recorded in a formal calibration report.
Immersion Depth
Heat transfer along the stem of the sensor causes the internal element to sit at a different temperature than the surrounding medium. Proper rtd calibration requires sufficient immersion depth in a stable temperature bath to minimize this conduction error. Insufficient depth leads to a reading that is biased toward the ambient laboratory temperature.
Excitation Current
Dissipation of electrical power within the sensing element generates internal heat that raises the temperature above the environment. During rtd calibration, the measuring current is kept low, typically one milliampere or less, to prevent self heating.
Stability Check
Cycling the sensor between its minimum and maximum operating temperatures reveals any shifts in the base resistance. An rtd calibration often includes a measurement at the ice point both before and after exposure to high temperatures. Stability is the primary concern.